Choosing the Right Solar Charge Controller/Regulator. Motorhome solar panel controller

Choosing the Right Solar Charge Controller/Regulator

A solar charge controller (frequently called a regulator) is similar to a regular battery charger, i.e. it regulates the current flowing from the solar panel into the battery bank to avoid overcharging the batteries. (If you don’t need to understand the why’s, scroll to the end for a simple flow chart). As with a regular quality battery charger, various battery types are accommodated, the absorption voltage, float voltage can be selectable, and sometimes the time periods and/or the tail current are also selectable. They are especially suited for lithium-iron-phosphate batteries as once fully charged the controller then stays at the set float or holding voltage of around 13.6V (3.4V per cell) for the remainder of the day.

The most common charge profile is the same basic sequence used on a quality mains charger, i.e. bulk mode absorption mode float mode. Entry into bulk charge mode occurs at:

• sunrise in the morning
• if the battery voltage drops below a defined voltage for more than a set time period, e.g. 5 seconds (re-entry)

This re-entry into bulk mode works well with lead-acid batteries as the voltage drop and droop is worse than it is for lithium-based batteries which maintain a higher more stable voltage throughout the majority of the discharge cycle.

Lithium batteries

Lithium batteries (LiFePO4) do not benefit from re-entry into a bulk mode during the day as the internal impedance of the lithium batteries increases at high (and low) states of charge as indicated by the orange vertical lines in the chart below and it is only necessary to occasionally balance the cells which can only be done around the absorption voltage. A related reason is to avoid the Rapid and large variation in voltage that will occur in these regions as large loads are switched on and off.

Lithium batteries do not have a defined “float voltage”, and therefore the “float voltage” of the controller should be set to be at or just below the “charge knee voltage” (as indicated in the chart below) of the LiFePO4 charge profile, i.e. 3.4V per cell or 13.6V for a 12V battery. The controller should hold this voltage for the remainder of the day after bulk charging the battery.

The Difference Between PWM and MPPT Solar Charge Controllers

The crux of the difference is:

• With a PWM controller, the current is drawn out of the panel at just above the battery voltage, whereas
• With an MPPT solar charge controller the current is drawn out of the panel at the panel “maximum power voltage” (think of an MPPT controller as being a “Smart DC-DC converter”)

You often see slogans such as “you will get 20% or more energy harvesting from an MPPT controller”. This extra actually varies significantly and the following is a comparison assuming the panel is in full sun and the controller is in bulk charge mode. Ignoring voltage drops and using a simple panel and simple math as an example:

Battery voltage = 13V (battery voltage can vary between say 10.8V fully discharged and 14.4V during absorption charge mode). At 13V the panel amps will be slightly higher than the maximum power amps, say 5.2A

With a PWM controller, the power drawn from the panel is 5.2A 13V = 67.6 watts. This amount of power will be drawn regardless of the temperature of the panel, provided that the panel voltage remains above the battery voltage.

With an MPPT controller the power from the panel is 5.0A 18V = 90 watts, i.e. 25% higher. However this is overly optimistic as the voltage drops as temperature increases; so assuming the panel temperature rises to say 30°C above the standard test conditions (STC) temperature of 25°C and the voltage drops by 4% for every 10°C, i.e. total of 12% then the power drawn by the MPPT will be 5A 15.84V = 79.2W i.e. 17.2% more power than the PWM controller.

In summary, there is an increase in energy harvesting with the MPPT controllers, but the percentage increase in harvesting varies significantly over the course of a day.

PWM:

A PWM (pulse width modulation) controller can be thought of as an (electronic) switch between the solar panels and the battery:

• The switch is ON when the charger mode is in bulk charge mode
• The switch is “flicked” ON and OFF as needed (pulse width modulated) to hold the battery voltage at the absorption voltage
• The switch is OFF at the end of absorption while the battery voltage drops to the float voltage
• The switch is once again “flicked” ON and OFF as needed (pulse width modulated) to hold the battery voltage at the float voltage

Note that when the switch is OFF the panel voltage will be at the open-circuit voltage (Voc) and when the switch is ON the panel voltage will be at the battery voltage voltage drops between the panel and the controller.

The best panel match for a PWM controller:

The best panel match for a PWM controller is a panel with a voltage that is just sufficiently above that required for charging the battery and taking temperature into account, typically, a panel with a Vmp (maximum power voltage) of around 18V to charge a 12V battery. These are frequently referred to as a 12V panel even though they have a Vmp of around 18V.

MPPT:

The MPPT controller could be considered to be a “Smart DC-DC converter”, i.e. it drops the panel voltage (hence “house panels” could be used) down to the voltage required to charge the battery. The current is increased in the same ratio as the voltage is dropped (ignoring heating losses in the electronics), just like a conventional step-down DC-DC converter.

The “Smart” element in the DC-DC converter is the monitoring of the maximum power point of the panel which will vary during the day with the sun strength and angle, panel temperature, shading, and panel(s) health. The “smarts” then adjust the input voltage of the DC-DC converter – in “engineering speak” it provides a matched load to the panel.

The best panel match for an MPPT controller:

• The panel open circuit voltage (Voc) must be under the permitted voltage.
• The VOC must be above the “start voltage” for the controller to “kick in”
• The maximum panel short circuit current (Isc) must be within the range specified
• The maximum array wattage. some controllers allow this to be “over-sized”, e.g the Redarc Manager 30 is permitted to have up to 520W attached

Choosing the Right Solar Controller/Regulator

The PWM is a Good Low-Cost Option:

f or solar panels with a maximum power voltage (Vmp) of up to 18V for charging a 12V battery (36V for 24V battery, etc).

When the solar array voltage is substantially higher than the battery voltage e.g. using house panels, for charging 12V batteries

An MPPT controller will yield higher returns compared with a PWM controller as the panel voltage increases. I.e. a 160W panel using 36 conventional monocrystalline cells with a maximum power amp of 8.4A will provide around 8.6A at 12V; while the 180W panel having 4 more cells will provide the same amperage but 4 additional cells increases the panel voltage by 2V. A PWM controller will not harvest any additional energy, but an MPPT controller will harvest an additional 11.1% (4 / 36) from the 180W panel.

For the same principle, all panels using SunPower cells with more than 32 cells require an MPPT charge controller otherwise a PWM controller will harvest the same energy from 36, 40, 44 cell panels as it does from a 32 cell panel.

Solar Charge Controller Features and Options

Boost MPPT Controllers

“Boost” MPPT charge controllers allow batteries to be charged that has a higher voltage than the panel.

Combined MPPT and DC-DC Chargers

The MPPT function is a natural adjunct to the DC-DC charger function and there are several quality brands that provide this with more under development. A single unit can be used by itself, as it automatically switches between alternator charging and solar charging. For larger systems, our favoured arrangement is to use a separate MPPT controller for the fixed roof-mounted panels and use the combined MPPT/DC-DC with portable panels. In this case, an Anderson connector is placed on the exterior of an RV which is then wired to the solar input of the MPPT/DC-DC unit.

Note that the battery capacity must be sufficient so that the combined charging current from simultaneous charging from the alternator and the roof solar panels does not exceed the manufacturer’s recommended maximum charging current.

Cheaper Options

Cheap controllers may be marked as an MPPT but testing has shown that some are in fact PWM controllers. Cheap controllers may not have the over-voltage battery protection which could result in the battery being overcharged with potential damage to the battery; caution is recommended. Normally, due to the increased circuitry, MPPT solar charge controllers will be physically larger than PWM solar charge controllers.

Multiple Solar Chargers

Properly wired, it is possible to add multiple solar chargers (any combination of type and rating) to charge a battery. Proper wiring means that each solar charger is wired separately and directly to the battery terminals. This ideal case means that each controller will “see” the battery voltage and is unaffected by the current flow coming from other charge controllers. This situation is no different from charging a battery from the grid/generator at the same time as charging from solar. With modern controllers, the current will not flow backwards from the battery to the controller (excepting a very small quiescent current).

Don’t Make These 12 RV Solar Mistakes

by Scott Fox

Here’s How to Avoid the Most Common RV Solar Mistakes

I get lots of questions about our RV solar and battery system. The RV solar system is large and obvious on our roof. Unless air conditioning is required where we are camping, our solar panels provide for all our energy needs.

In fielding these questions, I have determined that many solar installations do not achieve the desired outcome. Here is my list on how to avoid the most common RV solar mistakes.

Buying RV solar panels you don’t need or won’t use

Buying solar you don’t need or won’t use is the most obvious error. If all you do is travel from RV park with hookups to RV park with hookups, you don’t need solar panels to recharge your batteries. Your batteries will recharge just as well and probably faster using the power at your destination.

If you occasionally spend the night without hookups during a quick stop on a longer journey, I would argue for more or larger batteries, not for solar panels.

When you start spending more than one day in a row camping at locations without electrical hookups, this argues for recharging your batteries with solar panels. Then the question becomes, how often do you camp this way? If only once or twice a summer, then a generator might be a better, less expensive answer. If you do get a generator, get a quiet one.

If your battery discharges overnight to a point of concern, you need a larger capacity battery or a lower draw from the battery. This does not argue for a solar panel to recharge your battery in the daytime.

Instead of RV solar or a generator, you could use your truck engine and alternator as a generator. Be careful here, small engine alternators are not designed to provide long-duration high amperage battery recharging. Be especially careful with this option with lithium batteries; they don’t resist the charge and can damage an alternator quickly.

Guessing at what you need

Most people don’t have any idea about how much electricity they use. The best way to tell how much electricity you use from a battery is by measuring consumption using a shunt-based battery monitor. I did this before installing solar on my two different RVs.

My choice is a Victron 712 model that reports discharge to my cell phone. A slightly less expensive option is the Victron Smart Shunt. There are even less expensive shunt-based battery monitors, but I don’t have any experience with them. If the battery monitor does not have a shunt, then choose a different product. Once you have a shunt-based monitor, then you can measure your electricity use. If you are only using voltage to determine usage, you are simply guessing. Here is an entire article on that subject: Battery monitor — the missing critical part.

Guessing is not a good substitute for measuring.

Once you know how much electricity you use, then you can start designing your RV solar system. Start designing by figuring out your battery size. A good rule of thumb is to size your battery so that you can operate for 24 hours without recharging. Once you have enough battery to run 24 hours, you can then determine how many solar panels you need to perform the recharge.

Installing panels that are not exposed to full sun

Any little shade kills the energy production of the panel. It is better to have a poor orientation on the panels than it is to have shade on the panels. Depending on how your system is wired, shade on one panel can even kill the energy production of the adjoining panel.

Solar panels are designed to sit in the direct sun. When they are in the shade, they sometimes can produce only 10% of their potential energy.

Installing panels flat on your roof

If solar panels are installed flat to the roof, their operating temperature will increase, and as this happens the output of the panel will decrease. The effect isn’t quite the disaster that installing panels in the shade is, but they will not perform nearly as well without air circulation behind the panel.

Be sure to allow for airflow under and around your solar panel.

Failure to account for true performance and expansion

Almost always, due to less than ideal orientation, your solar panel needs to be oversized by a factor of about 30%. If the panel says 100-watt output, you can count on about 70 watts of usable power per hour during the peak exposure hours, which is about five hours per day, even in the winter. Summer will give you about two extra peak exposure hours. Don’t expect a 100-watt panel to produce 500-watt/hours of usable energy each day.

Lead-acid batteries also degrade solar panel performance because they resist being charged. My guess is that when I was charging lead-acid batteries using my first solar panel system, I cut solar performance by more than half.

A good practice would be to run wire with the idea that someday in the future you may want to add more solar panels to your system.

Cheap RV solar panels

Solar panels should last 20 years. Some of the least expensive solar panels will only last a few years. Solar cells are extremely thin and since they are so thin, they do not tolerate vibration well.

Solar cells are about the same price regardless of where they are manufactured. Since the actual solar cells themselves are all about the same price, you have to ask yourself, “Why is this RV solar panel less expensive than a different panel?”

Did they cut corners on the aluminum frame, glass, or backing? Solar panels should be robust enough to keep vibrations to a minimum at the cell level. Cheap solar panels may cost more in the long run. I recommend higher quality RV solar panels with a good warranty by a company that has been doing it for a long time.

Cheap RV solar controllers

RV solar controllers are another place where installers try to cut costs. Does the controller have a large heat sink to dissipate extra energy? A good way to judge a controller is by its weight. It should be heavy. It should not have a fan. Fans fail and then the controller will overheat and die.

An aluminum heat sink doesn’t fail. A good solar controller may cost two or three times the price of the cheap models. I expect my controllers to never fail. Cheap solar controllers typically don’t last very long.

Cheap batteries

If you go to a big box store and buy a “deep cycle” RV/marine battery, you probably purchased a bad battery. Sealed lead-acid batteries are not good batteries for solar storage. The electrolyte in a flooded sealed lead acid battery will be gone just after the warranty expires.

Flooded lead-acid deep cycle batteries with refill caps can be good batteries. AGM batteries are good batteries. Here is an entire article on lead-acid batteries: Stop Using The Wrong Deep Cycle RV Battery

Batteries made from lithium iron phosphate are the very best deep cycle batteries. This is the ultimate deep cycle. They have much longer life spans, and when judged on life cycle costs are the least expensive batteries you can buy — but they cost lots more upfront. Here is an entire article on lithium iron phosphate batteries: Batteries Lead or Lithium

Undersized wires

The minimum wire size for any solar panel installation should be 10 gauge. Thicker wires, including very thick wires, and wires bigger around than your thumb (4/0 gauge) may be required in some locations.

It is so sad to see good solar panels incorrectly wired with thin wires. It makes you wonder how they messed this simple item up. Edison discovered that DC electrical systems didn’t work to power neighborhoods all because they were trying to use thin wires over long distances. Use the correct wires, which usually means thick wires.

Another obvious wire mistake is using indoor wire outside. Wires meant for interior use will degrade and be worthless in about a year when exposed to direct sunlight.

Too much weight

This problem can apply to solar panels, solar panel racks, and other stuff, but really the problem here is lead-acid batteries. Lithium batteries of the same size and shape almost always hold twice the energy as a lead-acid battery at less than half the weight of a lead-acid battery.

Given that lithium iron phosphate batteries are also the lowest cost batteries in the long run, and always work better than lead-acid batteries, the weight savings alone justify the cost. Here is a cost analysis of lead-acid batteries vs lithium batteries: Batteries Lead or Lithium

Ignoring portable RV solar panels

Portable RV solar panels have a huge advantage over fixed solar panels because you can point them at the sun. You can even track the sun as the day progresses to get much more energy from them than fixed panels ever could produce. Plus, you can park your RV in the shade and move the panels out into the sun. Here is an entire article on this subject: Portable Solar Panels

Don’t ignore the possibility of a portable RV solar panel.

Failure to have a backup power source

I can recharge my batteries from either solar or my generator (or both at the same time). In fact, I put the batteries in first and lived with them for eight months before I installed solar.

Here is an entire article about how to use your generator with solar: How To Use The Generator With Solar.

Here is an article on how to use your generator to recharge your batteries and live without solar: Boondocking Without Solar

Conclusion

Mistakes cost money; make a minor error and performance will suffer. Make the wrong mistake and the entire system won’t work, or won’t work for very long. I haven’t even addressed the most basic mistakes of not including fuses and switches in the right location. Avoiding mistakes in RV solar is not difficult but it requires diligence.

RVers looking for valuable how-to information have learned to go to the experts. Forums such as iRV2.com and blog sites like RV LIFE. Do It Yourself RV. and Camper Report provide all the information you need to enjoy your RV. You’ll also find brand-specific information on additional forums like Air Forums. Forest River Forums. and Jayco Owners Forum.

Related articles:

Scott Fox is a retired Navy pilot and flight instructor that has been traveling full-time in his RV for almost four years. Scott’s first experience with RVing started as a youth in a small travel trailer with his family. Overall his camping experience spans well more than fifty years. FoxRVTravel.com shares stories and explains some of the more technical aspects of RVing. Both this article and FoxRVTravel.com are freely given without financial compensation by this publisher or by anyone else in any way. He explains that he just wants to help people get the straight story with no strings attached.

Reader Interactions

Комментарии и мнения владельцев

The blog “HANDYBOBSOLAR” provides a wealth of information from a guy who has been using solar in his RV and off grid home for over TWENTY YEARS, he documents his experiences along the way. Ps he is a bit eccentric and a bit of cranky pants

I’m full time in a Roadtrek class b. I replaced the noisy gas hog Onan with a Honda 2200i. I built a custom rack on the back where the generator is inside a compartment until I need it. Then I unlock the door and slide it out. Most of the time it only has to run for several minutes as I nuke something in the microwave, so I can leave it locked on the carriage. If it needs to run a longer time I unlock it and place it on the ground where the exhaust will be blowing away from me. This has worked great for me now for three years.

It was not mentioned, if I change to lithium iron phosphate batteries, do I need to change out the converter that is keeping my batteries charged, to a lithium iron phosphate battery compatible converter

Scott, thanks for the great write up! So much applies to boating, and I was just discussing many of these items today with a fellow boater. I too am a fellow Navy pilot. wings 4/81, E-2’s west coast.

How would you suggest an RV owner charge their batteries with when the unit is parked in outside storage?

There is a small solar battery charger with controller (so it will trickle charge and/or shut down when the batteries are fully charged) for sale at Batteries Plus, most auto parts stores and on Amazon. I have also seen them at RV stores but they cost more. Make sure the charger and controller are for your specific type of battery. For example, Auto parts stores are more likely to only have a solar charger whose controller is for a gel or lead acid auto battery.

Hi Scott – I have a 1960 Vintage travel trailer this is going in for a restoration/remodel early next year and adding solar for boondocking is on the list. My ex-boyfriend had this all figured out but since we are not together anymore I’m trying to figure this out on my own. I definitely learned a few things from him and your article is a great guide and supplement for me as I navigate this on my own. Per your suggestions I will start with a battery monitor with Lithium batteries and see how much power I’m using first. I also love the idea of portable panels vs installed on the roof. Parking in the shade and putting the panels in the sun makes perfect sense. I will be following your articles and so appreciate the way your explain things. Thank you so much. You are my new solar system guru!! Tracy

Good advice on designing and using solar. First things first you need to determine the total watts and amperage you expect to be running at one time. This information can be found on the appliances. I boondock 90% of the time anywhere from the NW to SW with a few trips to the eastern states. I run everything in my travel trailer including the A/C, Frig and Microwave off my solar and battery bank. I have three 330 watt REC split cell panels. The REC panels do not degrade in shade like most panels due to their “split cell” design. For batteries I have three 100ah AGM deep cycle VRLA batteries driving a 2000 watt AIMs inverter. My solar charger is a Victron 150/70. For my A/C I installed a Smart start to reduce the initial power needs. Also, all wiring is 8 AWG except for paralleling the batteries and the run to the inverter which is 2 AWG. My advice is to learn all one can than do a lot of research of parts followed by plan, plan, plan first. Research the different types of solar panels and solar chargers. Learn about batteries so you can make the best choice. It’s best to do a little overkill that to have a system that is too small. I also like lithium batteries; however, I calculated that I can change out my AGM’s four times before equaling the up front cost of lithium.

I have a portable RV Solar Panel. It has charged up the battery but suddenly nothing in the RV was working: lights, water pump, awning. I detach the solar panel from my battery and now everything works. Any ideas why?

Given where we are with climate change and energy costs, I find it disapointing how quickly the use of inefficient and highly poluting generators are recommended. In addition, over a lifecycle, generators are not more expensive per kWh than solar. We all have to do our part, sometimes spending a little more for the greater good. An example would be if we replace Windows in our house; should we spend more for insulated or not? Last I checked the payback for insulated Windows was approx 20 years. Even so to save energy and reduce the use of fossil fuels most of us will spend more on insulated Windows.

Too many issue with solar panels to charge your deep cycle batteries. Save the headache to get yourself a 2000 watt inverter generator to charge your batteries, and power can be had even if the sun is not shinning,like when it is overcast, raining, or at night. Now, what batteries to buy. Best is never what you want or need. If you are going a few trips a year, deep cycle lead acid battery from Walmart will suffice. Yes, there are pros and cons. But, they cost a lot less than lithium ion deep cycle batteries, and without the problem of not properly charging them. Yes, they have a better power profile than lead acid batteries, but again. they are much more expensive.

Got a question. I have two rather new lead-acid batteries in my class C. Can I link a FePO to the lead batteries to get more power between charging?

How To Choose The Best Solar Charge Controller For Your RV Or Camper Van Conversions

Solar Charge Controllers are an essential aspect of your solar system. They communicate between your solar panel and battery storage to ensure everything is running smoothly, which will extend the lifespan of your batteries.

The amount of solar charge controller options on the market can feel overwhelming, but there is certain to be a solar controller style that will maximize your entire RV solar power setup

To find the best fit for your RV or DIY van conversion, research past the basics of solar charge controllers of various voltages and sizes to understand what your solar array necessitates.

Besides this you need to ensure that the solar charge controller you choose can work with the type of battery you have, and your solar panel set-up to find the perfect charger for your entire system.

This article will help you understand your choices by exploring the role your solar charge controller will play in your larger solar system and examining the pros and cons of each solar charge controller option (PWM and MPPT).

We’ll analyze common technical features of solar charge controllers and look at some of the best solar chargers on the market to find the perfect system to power up your solar array.

What Are Solar Charge Controllers?

Solar Charge Controllers are voltage regulators that keep your batteries from overcharging. During the day, the controller ensures your deep cycle batteries aren’t being fed too much solar energy, damaging the battery’s internal components.

When the sunlight disappears, the controller makes sure power isn’t running backwards to your solar panels, blocking reverse currents.

It is an essential aspect of your overall solar system. Without a solar charge controller, you risk irreversible damage to your battery and a shorter lifespan for your solar panels.

How Do Solar Charge Controllers Work?

A Solar Charge Controller works as the middleman between your battery system and your solar panels. Your batteries will communicate with your solar charge controller, which will pass that message along to the solar panels.

The energy current flows into the controller’s semiconductor, which opens or closes depending on your battery’s current needs.

Each deep cycle battery has its own voltage capacity and any volts above that work against your battery’s health.

A Charge Controller regulates the voltage acquired from the solar panels and opens or restricts the energy flow from the panels depending on what your battery needs.

They have overload protection, which prevents your battery system from overheating when faced with too much current, and low voltage disconnects to automatically disconnect your battery before the battery over-discharges and damages itself.

Two Main RV Solar Charge Controller Styles

Solar Charge Controllers come in various shapes and sizes that all fulfill different functions and have varying strengths and weaknesses.

No matter what your set-up mandates, You can be sure there is a Solar Charge controller that is a perfect fit for you. Most controllers are split into two different categories:

• Pulse Width Modulation (PWM) Charge Controller
• Maximum Power Point Track (MPPT) Charge controller

The first step towards finding the suitable controller for your rig is understanding these two categories and deciding which one will work for you.

PWM Charge Controllers

Pulse Width Modulation charge controllers work like a heartbeat. Controlled pulses of energy are sent from the solar panel to your battery system instead of a constant flow of energy.

The controller will communicate with your battery to get up-to-date information on what it needs, which affects the beat of the pulsation.

Your fully charged battery doesn’t need a long pulse of energy. A PWM controller can understand when to trickle charge your battery and when to send a more prolonged burst of energy. This makes them highly adept for less energy-intensive situations.

These devices won’t handle much more than a 12v solar panel array, and if you have multiple solar panels in your set-up, you’ll need to ensure they are wired in parallel.

At maximum efficiency, these controller types will be able to convert 75% of your solar panel energy draw into usable battery charge.

MPPT Charge controller

MPPT Controllers can handle larger solar arrays. They are heavily favored by RVers seeking to live in their campervans full time or those expecting to get off-grid for weeks at a time.

In addition to communicating with the battery system to understand what charge level your system needs, MPPT charge controllers can sophisticatedly communicate with your solar panels to find the perfect operating voltage.

This communication with your solar panels is where the MPPT gets its name. The device tracks your solar draw to maximize power, which brings up to 30% more charge than a PWM controller.

MPPT’s also take care of converting your solar panel’s voltage power into an energy format that is more digestible for your battery system.

They can alter the volts into amps, which prevents your system from wasting any energy drawn in by your solar panels.

MPPT’s can convert 96% of your solar draw into usable energy for your vehicle.

What Is Better MPPT Or PWM?

PWM controllers can get a more straightforward job done at a more affordable price point than an MPPT charger, but MPPT controllers are built to handle more extensive setups and are more reliable for long-term use.

If you just have a few lights and fans to power up on weekend trips, you won’t need much more than a PWM controller and a full battery before you head out.

If you have a heavy-duty system or expect to rely on your solar charger for weeks at a time, you should commit to investing the extra money for an MPPT charger.

Multiple solar panel systems are a good indicator that you need the extra oomph provided by an MPPT controller.

If you just want to trickle charge your battery to ensure it’s ready to roll when you are, the efficiency of PWM is all you need.

Any system more significant than two solar panels or 150W’s will have to rely on the more extensive charging capabilities of an MPPT solar charge controller.

How to Select the Best Solar Charge Controller for Your RV

Now that you know the two common types of solar charge controllers, you can start to examine the minute details of each model to decide what your solar array needs and what fluff you can skim off the top.

Before you even begin looking for a controller, you should understand the maximum wattage of your solar panels draw and think about the long-term goals of your system.

If you are just starting on your solar journey but want to upgrade your abilities over time, you should ensure your controller can remain functional when you begin to bring in more solar charges.

Calculate the total amperage draw of your solar panels at peak power. This number will reflect exactly how much energy is brought into your panels when receiving maximum exposure to the sun.

It is essential that you slightly overestimate this energy draw, as you don’t want your solar charge controller to have to constantly strain itself to keep up.

Once you know your solar panel amperage, figure out your battery bank’s maximum voltage.

Whatever your solar panel amps bring in is irrelevant if your battery bank can’t handle more than 80 amps, as your solar charge controller won’t force energy into your battery.

You can have six solar panels drawing in hundreds of amps per hour, but if your battery can’t wield that extra energy, your solar controller will be forced to render that power useless.

A safe bet is to find these two voltage numbers and select a charge controller capable of 25 % more power push than the lower of the two voltages.

If you plan on upgrading your battery system or solar panels in the future, you’ll have to upgrade your solar charge controller, too, so be sure to keep that in mind when making your purchase.

Extra features

A solar charge controller’s only real job is energy transfer. However, modern technology is flooded with convenient options that will make your solar system better.

Solar charge controllers have received their fair share of upgraded features that make using your solar array easier than ever.

Bluetooth

High-tech solar controllers pack in tons of data that reports how efficient your system is harnessing solar energy at every step of the process.

Some of the best controllers include Bluetooth technology that lets you access all of this information at the push of a button.

You’ll be able to understand how much power your solar panel is providing, how much of that energy is reaching the controller, and the volts that make it from the controller to your battery.

Having access to all this information makes it easier to understand which aspects of your system excel and which pieces hold everything back.

A Bluetooth system will also constantly inform you of your battery’s charge level, so you won’t have to spend your days wondering whether or not your battery is nearing critical status.

Manually Adjustable Voltage

Every type of battery has different voltage needs. Most modern batteries are built to work with solar systems, but the specific type of battery you use will ask something different out of your solar charge controller than the others.

To ensure that everything stays on the same page, modern charge controllers sometimes include the ability to manually dictate the type of battery the controller will be charging, allowing your controller to give your battery precisely what it needs.

On/Off Switch

A simple addition of an On/off switch can add years onto the lifespan of your system.

Most RVers hope to hook their solar panels onto their roof, connect those panels to their battery via a solar charge controller, and not have to deal with things for a while.

Solar panels can’t help themselves from drawing in energy from the sun whenever they feel the rays.

If your solar charge controller can’t be turned on and off, you’ll have to disconnect the fuse from your battery bank every time you want to stop your solar panels from charging your batteries.

Overcharging your system can erode the interior materials of your batteries and eventually destroy your battery’s capabilities.

If you want to save space by putting your battery bank in a hard to reach area, purchasing a charge controller with an on/off switch will save you from having to rummage around amongst your wires every time you plan on leaving the vehicle parked in the sun for a few days.

Red flags

Many Solar Charge Controller advertisements say all the right things. It’s not always so easy to tell if the product can truly walk the walk.

If you find a product at a low cost compared to other controllers capable of the same outputs, check to see if it is UL-certified.

UL certification is a process conducted by a company called UL, whose sole purpose is to maintain high standards in technological equipment.

Any product that has earned a UL certification can be considered safe from malfunction.

Some cheaply made solar charge controllers produce electrical noise as a byproduct, which can interfere with the frequencies of other electronic devices in your vehicle.

UL certifies that the controllers are safe, efficient, and won’t clog up your airwaves.

Your solar charge controller works as the heartbeat for your entire electrical charge system.

Avoid cheaply made products that make big promises in favor of high-quality chargers with plenty of reviews and warranties included.

Best RV Solar Charge Controllers

To help you navigate the complex solar charge controller field, we’ve selected 5 of the best solar charge controllers that all work well in different scenarios.

While these solar charge controllers may fulfill different niches, each one was made with high-quality materials and adequately tested to be recognized as the best options in a field full of choices.

Here are the 5 best solar charge controllers for your RV or camper van conversion:

• Victron 100/50 Smart Solar MPPT Charge Controller – Best Overall
• Renogy Adventurer Li- 30A PWM – Best PWM
• MidNite Solar Classic 150 MPPT Charge Controller – Best High End
• Renogy Li 40a MPPT Charge Controller – Best Budget MPPT
• ALLPOWERS 20A Solar Charger Controller – Best Budget PWM

The Best Solar Charge Controllers For Campervans Motorhomes

A solar charge controller is a piece of equipment that takes the electricity produced by your solar panels, converts, and optimises it for storage in your leisure batteries, so that you can run the electrical equipment on your campervan, motorhome or RV.

There is an awful lot of science involved when it comes to solar systems and controllers, however in this post we will stick to the basics so that you can easily decide what charge controller might best suit your campervan, motorhome or RV.

Disclaimer: Some links in this article are affiliate links, which means that if you purchase through them I receive a small commission, at no extra cost to you. This helps cover the cost of running this blog. Thanks for your support!

The Best Campervan Solar Charge Controller

Short on time and want to get straight to the nitty gritty? No worries! From our research and experience of living full time in our van for 2 years, the best solar charge controller is the Victron Smart Solar MPPT charger since it’s reliable, robust, compact and has bluetooth monitoring so can be fitted anywhere in the van.

For more information, read on below.

Why Do We Need a Solar Charge Controller?

Solar panels will produce electricity at a different voltage to the one your campervan utilises. Most UK campervans and motorhomes will operate using a 12 Volt power system with a 12V battery or batteries. Systems that run on 24 Volts are possible but normally only on larger vehicles such as large motorhomes, trucks and buses.

A solar charge controller takes the power from your panels and converts it into the power required by your battery system (for example 12V). The best solar charge controllers do this in a very efficient way which offers a level of protection to your system, whilst maximising the efficiency and lifespan of your batteries.

Most modern charge controllers can work with most or all of the batteries available for campervans. To better understand campervan leisure batteries, be sure to read this guide.

There Are 2 Types of Solar Charge Controller to Consider

PWM – Pulse Wave Modulation

Without going into too much detail, this is older technology and as such is tried and tested, reliable and robust.

These are best suited to smaller, simpler solar setups and ideal if you are on a very tight budget. Also if your van spends most of the time parked up on the drive and is used for occasional trips, this might be a cheaper, simpler option.

These charge controllers are best suited when the power produced by the solar panels closely matches that of your batteries. Be aware there are many cheap generic PWM chargers on the market that may not provide good reliability.

MPPT – Maximum Power Point Tracking

I would suggest this is the best option for the vast majority of systems, especially where maximum performance is required. MPPT controllers are up to 30% more efficient than PWM controllers and are best suited to systems where the power produced by the panels is higher than the power required by the batteries.

Unless you are specifically looking for a small or basic setup, I would personally not look beyond an MPPT charge controller. We initially fitted a PWM controller to our 270W panel and struggled for power in a UK summer. When we changed to our 30A MPPT charger the difference was like day and night and our controller has now run non-stop ever since.

Modern MPPT chargers are reliable and will accurately monitor your charging system and condition of your batteries. They work well in all conditions and are compatible with all types of battery.

For most DIY campervan conversions, the solar panels are usually mounted flat on the roof of the van rather than angled towards the sun, so maximising the output from your charge controller is crucial to obtain maximum performance.

Considerations When Choosing a Solar Charge Controller

How much power will I need?

Before choosing any part of your solar system setup you need to work out how much power you will use. This involves calculating the electrical demand of all appliances such as your fridge, lights, inverter, heater and gadgets.

The easiest way to determine this is through using an online calculator which will allow you to work out the size of panel and battery storage required. I suggest you consider rounding up the panel sizes a calculator comes up with, as there will always be cloudy or rainy days plus over capacity will extend your vanlife season.

If you need your solar system to power you through winter vanlife, your calculation needs to take the typical sunlight hours into consideration but also remember that a solar panel fitted flat to the roof will not produce much when the sun sits so low in the sky.

How big does my charger need to be?

Charge controllers are rated in Amps. For example, a small controller might be 10 amps, then you can get 15A, 20A, 30A and so on. To work out the size of controller required, there is a fairly simple calculation which is: W/V=A

To work out what size controller you need, take the total output of your panel or panels quoted in Watts then divide this figure by 14.4 if using a 12V system (Divide by 28.8 for 24 V systems). This will give you your maximum output in Amps. For optimum efficiency your charge controller needs to be one third larger than this figure.

• Our van is fitted with a 270W panel and 12V Leisure battery

• 270w divided by 14.4v = 18.75A

• 18.75 33% = 24.93

• so we opted for a 30A charge controller, which is the closest to one third more than 18.75.

If you had 400W of output from your panels then it would be advisable to go with a 40A or 45A controller for optimum performance.

Am I likely to add more panels in the future ?

If you are likely to add more capacity in future then it might be worth considering going for a higher capacity charge controller from the onset. However if you have worked out your power requirements correctly there should be no need to add more. For more information on the best solar panels for campervans, take a look at this guide or if you’re unsure whether to get rigid or flexible solar panels, read this guide.

How should I fit my charge controller?

It is crucial to fit your controller correctly to prevent damage. If you have any doubt, then get professional advice. Most units need to be connected to a battery before attaching your solar panels (or switching them on).

A suitable isolator/trip switch should be installed between the panels and your controller to protect the controller from overloads and also to allow you to isolate the controller from the panels before changing the battery or working on the wiring in any way.

Wiring up your charge controller correctly is vital if you want to get the best performance and lifespan from it. If in doubt hire a professional to fit or advise you.

Where am I most likely to fit my charge controller?

Many units come with an integral display which shows charging information. If you go with one of these you will most likely want to fit it somewhere you where you can read the screen to monitor your battery charge etc. Units without a screen can be fitted anywhere and maybe out of the way so long as there’s adequate ventilation for them. You can also get a separate remote display for some controllers.

Many modern charge controllers can now be connected to an app on your smartphone, so you can monitor the performance of your solar system.

The 4 Best Solar Charge Controllers For Campervans

Victron Smart Solar MPPT Charge controller – The best MPPT charge controller

You won’t go far wrong with this high quality and versatile charge controller that should keep your solar system performing at its best for years to come. Top of the range performance for campervans, mobile homes and static installations alike.

Why buy it?

• A well respected brand in the industry.
• Well made reliable units should last for years.
• Easy to install and operate.
• Compact.
• Available in a wide range to handle different power outputs.
• Since these controllers have no screen, they can be fitted in variety of locations.
• A remote display is available should you require one.
• Possible to monitor using a smartphone via bluetooth.
• Has many Smart features to ensure maximum performance and lifespan of your whole system.
• Built-in protection for your batteries.

Renogy Rover Li MPPT charge controller – The best MPPT charge controller with a screen bluetooth monitoring

A top reliable option from Renogy with a built-in screen and optional bluetooth for smartphone monitoring. This is an ideal choice of charge controller for use in a campervan.

Why buy it?

• Good brand with a range of compatible equipment suitable for campervans.
• Great reliability.
• Nice clear screen.
• Optional smartphone monitoring (opt for bluetooth module)
• Offers great protection to batteries and Smart charging capability.
• Support available from recognised brand.
• Useful information and tools available on Renogy website.

Epever Tracer MPPT charge controller 40A – The best value MPPT charge controller

This is a neat charge controller with a simple display that offers reliable control of your solar system.

Why buy it?

• Reliable: We have a 30A version of this charger which has been operating non-stop since we fitted it in 2020.
• Nice built in screen displays: Power produced by panels in Amps, battery charge %, battery temperature and total power produced.
• Easy to set up and use.
• Good value option.
• Offers good protection and optimal charging of batteries.
• Easy to install.
• Good support if bought from Bimble Solar.

Renogy Voyager 20A PWM charge controller – The best PWM charge controller for those on a budget

This reliable unit from Renogy is a good budget option. It’s waterproof so can be used in specific installations such as external fitting or on boats.

Why buy it?

• A reliable no nonsense controller.
• Waterproof: Ideal for boats, fitting outside such as caravan or shed installations, or in areas where damp may be a concern.
• Great for those on a budget.
• Compact.
• Good option for small systems, such as where you only want to run some lights and a phone charger. For example, if you only use your campervan for occasional weekends.
• Constructed of fewer components therefore less likely to malfunction and cheaper to replace.
• Ideal for remote applications such as a static caravan, shed or semi-permanent camp.

Final Thoughts on Campervan Charge Controllers

When fitting a solar system to your campervan or motorhome it is important to fit good quality components which are compatible with each other and your requirements. Your charge controller is central to your whole system and as such investing in efficiency and reliability is a must. A good charge controller can extend the life of your batteries and keep you informed as to the performance of your system overall.

There are many products available and I have listed four of the best options for your system. All of these charge controllers come in a range of options to handle various power requirements and will provide good performance and reliability for years to come.

MPPT charge controllers are more efficient and are recommended for full-time vanlifers whereas PWM charge controllers are better suited to small solar setups such as those used by part-time van dwellers.

Be sure to work out your power needs before buying any products. Renogy and Bimble both have good online calculators and other tools to help design a good solar system. With all Solar charge controllers it is crucial carry out installation correctly to avoid damaging them. Please ensure you follow fitting instructions correctly and get professional help if you have any doubt.

Louise is a Mountain Leader and Outdoor Activity Instructor from South Wales. As a former Tour Leader and Snowboard Instructor she has spent the last 15 years travelling Asia, Africa and the Americas. Louise is a published photographer and is currently based in the UK.

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The Best Solar Charge Controllers for RV of 2023

Are you having issues finding the best solar charge controller for RVs? It’s important to know you aren’t alone, as many rig owners struggle with this task. There are a lot of moving parts, which causes much more confusion than necessary.

However, I intend to reduce these issues by guiding you through the entire process. This guidance will include various essential topics, such as determining buying factors, benefits, and what type fits your needs the best. I’ll even review 14 solar charge controllers, which I find to be the best available.

All these discussions should supply a buyer with everything needed to make the right buying decision. Keep reading, and I’ll make sure this entire process ends with your perfect choice.

Best Overall	Budget Friendly	Easy To Use
Preview	Renogy Wanderer Li

Top-tier Solar Charge Controller for Your RV Reviews

This section will contain 14 reviews to provide a better feeling for what’s available. These RV solar controller reviews will be vital in ensuring you know what a top-tier solar charge controller looks like and offers an RV owner.

Renogy Wanderer Li 30A 12V PWM Solar Charge Controller

Renogy’s Wanderer Li 30A 12V PWM Solar Charge Controller couldn’t have a better reputation among rig owners who utilize solar power. It’s equipped with multiple features capable of using this renewable resource much easier.

An excellent example of one is its LED indicators, which alert users to pivotal battery info and charge status. These lights will ensure you always know what’s happening with your rig’s battery during its charging process.

I was also a massive fan of this product’s battery lithium battery mode. This design feature provides the versatility that most other PWM options can’t match. After all, this mode allows the controller to work with many 12V battery banks and types, including most 12V lithium models.

The device’s easy-to-use interface is another winning trait. Multiple buyers made it a point to note how simple using this device was compared to other models. As someone who values simplicity, I found this praise extremely appealing.

It only becomes easier when you factor in the product’s RS232 port, which allows users to connect to Renogy’s Bluetooth module. This feature provides the benefit of adjusting and monitoring everything from your smartphone through an app.

But none of these features can even compare to this product’s best one, its price tag. You aren’t going to find many solar charge controllers capable of offering effective results at this cost. It’s always nice to come across a bargain when searching for a device like this one.

I was a bit disappointed to see this model didn’t come with a battery temperature sensor built-in. However, it does have a port for one, which means you can buy that sensor separately. It’s a bit of a hassle, but this device’s affordable price might definitely be worth it.

EEEKit RV PWM Solar Charge Controller

If you’re looking for a simple model, EEEKit’s RV PWM Solar Charge Controller has you more than covered. It’s considered one of the most straightforward RV solar controllers available today. But don’t think its simplicity means it doesn’t have some outstanding features.

For instance, the product’s large LCD display is a feature that everyone will love. It’ll make sure reading the status and data info doesn’t require much effort. The icons and screen are very visible and aren’t hard to see even when a ray of sunshine enters your rig.

It also helps that this display allows you to switch modes and adjust specific charging process parameters easily. As a result, a user will never feel out of control when using this RV solar panel controller.

You should find this product’s various built-in protections appealing as well. These include short-circuit, reverse, overload, and open-circuit protections, ensuring that everything ends up running smoothly.

In fact, these protections will increase your battery’s lifespan and efficiency by a significant margin. Each one ends up being an excellent addition to ensure you can use both the charge controller and your rig’s battery for many years.

But again, the device’s main attraction is its easy installing and using processes. I don’t imagine anyone reading this article will have much difficulty setting it up or using it. Trust me; if I can do both, you should haven’t any issues.

I do wish the manufacturer got better reviews for its provided customer service, though. Many buyers felt the need to state their unhappiness with it in this PWM solar charge controller review section. But I don’t think this issue should make anyone take the product off their consideration list.

EPEVER MPPT 30A 12V/24V RV Solar Controller

One of the most efficient options available is EPEVER’s MPPT 30A 12V/24V RV Solar Controller. This product utilizes advanced MPPT technology to offer an efficiency rate of no less than 99.5%. It’s a result that’s almost unmatched by most of its competitors.

You should also be more than pleased with its 98% conversion rate. This aspect ensures the product can maximize the energy produced by your solar panels to charge up your solar power system.

If you aren’t impressed by these statistics, the overwhelmingly positive praise in this MPPT charge controller review section should provide a bit more sway. There’s no reason to believe this product won’t function and deliver the results its description guarantees.

The product’s isolated RS485 interface is another trait worth mentioning. It makes it easy to monitor and adjust parameters by using an app on your phone. You aren’t going to find a more user-friendly using process than one you can control in your hands.

As for its safety precautions, this EPEVER solar charge controller comes with several built-in protections. These include protections against over-discharging, overcharging, and PV reverse polarity to ensure your solar system performs safely and with more reliability.

The price tag of this particular device is the only issue it has. If money isn’t a concern, I don’t see any valid argument against purchasing this device. It has everything a person could want in one and offers beneficial results. What more could a rig owner want?

Victron SmartSolar MPPT 75/15 Solar Charge Controller

Victron’s SmartSolar MPPT 75/15 Solar Charge Controller tends to be a popular choice among rig owners because it’s one of the most advanced options available. Its design features top-tier technology, which provides it with aspects capable of offering excellent performance.

One of these aspects is the product’s usage of Bluetooth. As with any Bluetooth feature, it’ll ensure you can monitor and control the controller using a device like a smartphone. It makes sure you can operate the controller from almost anywhere.

This device also comes with access to Victron Remote Management Portal whenever the installed device uses your internet connection. It’s a feature capable of providing you with full control and power to this device regardless of the place or time.

As a result, these features work together to ensure you never miss a sunny day to charge your rig’s battery. Buyers were impressed with this product’s use of MPPT technology, which will prevent you from wasting any power produced by your solar panels.

The product’s load output function shouldn’t be overlooked, either. It’ll help prevent damage that might come from flat batteries to ensure further your batteries last a long time without issue. Honestly, any feature capable of increasing battery lifespan is always a winning one.

You should find the battery life feature impressive, too, as this aspect makes sure the SmartSolar attempts a 100% recharge process every day. If it can’t complete the recharge, this aspect will disconnect voltage daily, until your battery reaches full charge capacity.

But some customers did report a few shipping issues in this Victron solar charge controller’s reviews. It seems this product sometimes arrives later than expected or in damaged packaging. It shouldn’t stop you from considering this device, though, as its performance is worth dealing with these concerns.

OOYCYOO 12V 24V Auto 40/60/80/100A RV Solar Regulator

The OOYCYOO 12V 24V Auto 40/60/80/100A RV Solar Regulator is another MPPT controller that can provide effective tracking of your solar system’s charging process. It’ll ensure the power produced by your solar panels is used to their maximum efficiency.

Aside from its effective tracking results, buyers will also love its excellent durability. You can attribute this aspect to its ABS housing that offers resistance against heat, impact, and low temperatures. I can’t imagine a situation where this model wouldn’t perform to its usual high standards.

I was impressed by this product’s aluminum cooling teeth as well. This design aspect is included to promote better heat dissipation. As a result, it’ll keep the operating temperature low and reduce the risk of overheating.

The product’s LCD display is another fantastic inclusion to ensure you can easily track what’s happening. It’ll make sure you’re updated on important information, such as whether the battery and solar panels are connected to the controller.

You’ll also benefit from several other familiar features that I’ve discussed at length in our prior reviews. These include multiple layers of built-in protections, multi-stage charging, and being capable of working with various battery types.

Each of these features will only make this model more useful and appealing. It’s hard to imagine any rig owner being disappointed by what this RV battery charge controller offers. You even get a choice between nine color schemes.

But these many excellent features come with a rather significant flaw. As you might imagine, the price tag on this device is a bit excessive. You’ll have to shell out a considerable chunk of a change to benefit from these outstanding features.

RICH SOLAR 40-Amp 12V/24V MPPT Solar Charge Controller

Are you looking for a versatile solar charge controller? RICH SOLAR’s 40-Amp 12V/24V MPPT Solar Charge Controller could fit your needs perfectly. It’s capable of detecting both 12V or 24V DC system voltages automatically and with a top-tier efficiently.

This model is also compatible with numerous deep cycle batteries, including flooded, lithium, gel, and sealed. As a result, this device will have no issues appealing to a wide variety of situations needed for a solar charge controller.

You even get a choice regarding amperage as this comes in three variations: 20-amp, 30-amp, and 40-amp. RICH SOLAR clearly made an effort to ensure their product could work in as many scenarios as possible.

But if this product wasn’t effective, none of this versatility would matter. This isn’t the case with our device here, because it uses MPPT technology. This technology allows the device to provide high tracking efficiency of no less than 99%, which is top-tier among these products.

You’ll also benefit from its overall design, which is made from die-cast aluminum. This design material will keep everything cool to reduce the risk of overheating. There’s no reason to believe the product will suffer from any durability issues with a design like this one.

I was pleased with this device’s RS232 port, which allows the user to use Bluetooth communication. As with some prior options, this feature ensures you can control the device from an app on your smartphone.

I was pleased with this device’s RS232 port, which allows the user to use Bluetooth communication. As with some prior options, this feature ensures you can control the device from an app on your smartphone.

Outback Flexmax 80 FM80 MPPT 80 AMP Solar Charge Controller

Outback’s Flexmax 80 FM80 MPPT 80 AMP Solar Charge Controller happens to be the most expensive option on our entire list. But there’s a reason for this higher price as it has features these other options can’t touch.

For instance, this solar charge controller is programmable to charge voltages ranging from 12 volts to 60 volts. This amount of variation isn’t something most of our other options have a chance at competing against.

I was also impressed with this product’s backlit display, which contains 80 characters. This display will offer more information about the process’s status than any other charge controller. The screen will even log system performance data for a whopping 128 days.

As a result, it’ll ensure you know everything needed to keep track of what’s going on with your solar panels and battery. The product also utilizes active cooling technology and thermal management cooling to ensure it provides its maximum rating even in temperatures reaching 104 F.

It doesn’t hurt that both the product’s using and install processes are straightforward, either. In fact, I found both tasks to be an absolute breeze during my experience with the device. The included directions being easy to read and follow certainly helped as well.

A lot of buyers complimented on Outback’s customer service, too, which is a rarity in the consumer world. Honestly, I couldn’t find a single person willing to give their client service a bad review.

I just wish this product didn’t cost as much as it does, considering it fits everything I want in a charge controller. But anyone who’s looking for the best option won’t find one more equipped than this one.

ALLPOWERS 20A RV Solar Charger Controller

If you’re looking for an affordable option, buying the ALLPOWERS 20A RV Solar Charger Controller should be considered. It’s actually among the least expensive options on our entire list and doesn’t lack when it comes to high-quality features, either.

One of these features is the product’s easy install process. Numerous buyers even noted this product’s installation as a much simpler task than their prior controllers. Some were even shocked by how easy it was, considering the price tag.

I was also impressed by this product’s ability to offer top-flight heat dissipation. This aspect is essential because it keeps the core temperature down to avoid overheating. Due to this, the product can run effectively without any issues.

The two USB ports aren’t anything to overlook as well. Both these ports will become incredibly useful by ensuring you can help charge various products. It’s another aspect that points to ALLPOWERS’ willingness to make their products user-friendly.

You should also find yourself enjoying the product’s LCD display and multiple built-in protections. These features are vital in ensuring a safe and easy using process for whoever’s lucky enough to buy this fantastic product.

But even with all these great features, the central standout remains its price tag. Bargain buyers should be jumping at the chance to purchase this model from ALLPOWERS. It’s truly an impressive but affordable charger controller.

However, the device isn’t the most reliable when it comes to durability. This issue shouldn’t be too shocking, considering the price, but it was noted in a few reviews. I still think buying this model would be worth it, though, as its positives far outweigh this one negative.

Onesolar 60A MPPT Solar Charge Controller

Onesolar’s 60A MPPT Solar Charge Controller is an easy contender to win the title of best MPPT charge controller for the money. It gains this status with features like its real-time energy stats function, which keeps users fully aware of everything relevant to the charging process.

This feature makes it easy to see operating data and the working condition of the device. Of course, its clear and readable LCD display is helpful in this aspect. Both of these traits work together to make this model practical for the person using it.

I was also intrigued by this product’s ability to work with 12V, 24V, and 48V solar panels. This aspect makes the product a usable tool for a wide selection of rig owners. In each of these situations, the product’s MPPT technology usage has made it more than sufficient.

You don’t have to worry about safety issues, either, as it’s loaded with built-in protections: short-circuit, reverse polarity, overload, over-discharge, overcharge, overheating, and under-voltage. In other words, anything capable of going wrong has been accounted for by this Onesolar device.

Aside from its impressive performance, I was happy to see this model provides a bit of color choice. It might not seem like a big deal, but I always find it helpful to have some style options even with these devices. It’ll ensure you don’t have to deal with something you hate looking at during your RVing trips.

But I was a little annoyed with seeing a few buyers complain about durability issues. These types of problems aren’t what I expect from a top-tier brand like Onesolar. It’s also worth noting many other buyers were more than happy with their choice. It’s possible that these complaints were isolated incidents rather than the norm.

Renogy Rover 40 Amp MPPT 12V/24V Solar Charge Controller

You shouldn’t be surprised to see another Renogy, given the quality of their previous two, on our list. Renogy’s Rover 40 Amp MPPT 12V/24V Solar Charge Controller separates itself from these other two models using MPPT tech.

As a result, buyers can expect better results from this model than the previous Renogy options. I was also pleased with the device’s ability to work with both 12V and 24V solar power systems.

The product’s four-stage charging process could benefit both system types greatly. In fact, it’ll work with the device’s ability to compensate for temperature to ensure your battery’s lifespan lasts much longer. Plus, it’ll increase your system’s overall performance.

You should also know this model is compatible with numerous deep cycle battery types, including lithium, flooded, gel, and sealed. It’s clear that this device from Renogy is ready to utilize its stellar MPPT tech in various situations without issue.

Other than these features, this device comes equipped with everything I’ve come to expect from a charge controller from this brand. These features consist of an LCD screen, LED indicators, aluminum heat sink, and Bluetooth capability.

I don’t see a single absent feature which I would want within this model. This brand did an excellent job covering all the bases in what a rig owner could need in a solar charge controller. It doesn’t hurt that it’s easy to set up and use, either.

However, I was saddened to see Renogy get lousy reviews surrounding their customer service. There are just a few complaints, but that is something I wasn’t expecting to encounter based on my prior experiences with the brand.

Xantrex 40-amp Solar Charge Controller

The Xantrex 40-amp Solar Charge Controller does its job without providing the user any difficulty or trouble. It can offer this benefit due to its reputation for having a quick and simple installation process.

I was slightly shocked by how easy it was because this model does contain some advanced features. But the directions were clear, precise, and easy to follow for even a person who isn’t great with electronics like me.

Beside this simple install, I was also happy with this product’s powerful microprocessor that increases and maximizes your battery’s lifespan. You can rest easy knowing this aspect is built with stability in mind and has a low noise operation level.

The product’s 3-stage battery charging cycle is another appealing trait. This cycle will ensure that the current settings and voltage match your battery’s state of charge accurately. Due to this, the charging process will be as fast as possible and keep your battery in peak shape for longer.

You should find comfort in this product’s meeting both UL and cUL safety standards as well. These certifications prove the device went through extensive testing before being released onto the market. It’s another layer of safety precaution to ensure nothing dangerous occurs from its usage.

Buyers will also be impressed by its ability to work with 12V, 24V, or 48V systems. In each of these situations, the product’s PWM technology has been proven to be more than adequate in monitoring a solar power system’s charging process.

It was a bit worrying to see this model have a few reviews complaining about its longevity. The product seems to start having durability issues after a few years of regular use. It’s not an ideal situation, but it’s still one of the best PWM solar charge controllers available.

Sunway Solar Panels 12V Solar Charge Controller

Rig owners who don’t intend to use their solar power all the time might think about getting Sunway Solar Panels’ 12V Solar Charge Controller. It’s a simple, practical device capable of tracking your solar system’s charging process with ease.

Most buyers end up enjoying the easiness of this product’s install process. This attribute comes from its versatile quick connect and disconnect clips. These clips ensure attaching the controller onto your solar panels and battery doesn’t require much effort.

I found this product’s LED indicators to be appealing as well. These indicators will tell a user when the battery’s either experiencing low voltage (green), charging effectively (yellow) or having high voltage issues (red).

These three indicators make the monitoring much more straightforward than expected on a low-priced model like this one. The product’s ABS plastic housing makes it more durable than anticipated as well.

I couldn’t believe people were praising the product for being rather tough in their reviews. Honestly, an adjective like tough isn’t what I expect when examining a bargain buy, such as this device from Sunway Solar Panels.

But again, the main attractions with this model come from its easy using process and affordable price. Bargain buyers shouldn’t sit on their hands and let this deal pass. It’s almost too good to be true, given the product’s stable features and performance.

I was a little disappointed to see this option wasn’t a waterproof solar charge controller. It could be somewhat problematic for an RV owner. However, this price tag and features make dealing with this hassle worth it.

Go Power! GP-PWM-30-Amp Solar Regulator

If you’re looking for a highly functional PWM type controller, Go Power! ‘s GP-PWM-30-Amp Solar Regulator might be a perfect choice. It comes with an extensive list of outstanding features, which any rig owner would find appealing.

One of these features is the product’s built-in USB charging port. This aspect got me excited because it ensures you can charge all sorts of devices, ranging from phones to laptops. It provides a bit more versatility than you might expect from a charge controller.

The product’s 4-stage charging process is another feature which caught my eye. It’ll prevent any overcharging from occurring when you charge your rig’s batteries. You can attribute this benefit to the vital fourth stage of equalization.

Its equalization stage will make sure every cell inside a battery bank gets charged at the same rate, which will ensure undercharging or overcharging isn’t an issue. This results in your batteries working for a more extended period and more productively.

Buyers were over-the-moon about this product’s LCD display as well. In fact, many of them made a point to praise it for being more user-friendly than their previous models. It’s always nice when one of these devices makes tracking the charging process an easy task.

I should also point out this product can work with various battery types, including lithium, wet cell, gel, and AGM batteries. It’s just another aspect which shows this model’s overall versatility and convenience.

But I wasn’t too thrilled to encounter two flaws within this RV solar controller’s reviews. A few customers noted that this product’s screws sometimes came loose, which offers some concern about its durability. Plus, it has a rather high price tag for a PWM model.

Renogy Adventurer 12V/24V PWM Charge Controller

Buyers looking for an option with easy-mounting capabilities need to consider Renogy’s Adventurer 12V/24V PWM Charge Controller. It was designed to flush mount right onto a camper or motorhome’s walls.

You should also love this product’s versatility as it’s capable of working with sealed, flooded, or gel batteries. Plus, it offers 12V and 24V compatibility to increase further the number of situations where it could be used effectively.

I found the product’s 4-stage charging more than sufficient as well. This four-stage process will help prevent batteries from suffering issues like over-charging and over-discharging. It’s a simple way to improve your battery’s longevity and performance within a motorhome.

As with our prior options, it has built-in protections to stop any further issues: overload, short-circuit, overcharging, and reverse polarity. The product even comes with a self-diagnostic system to add another layer of protection against system faults or install mistakes.

You can rest easy knowing that this model is more than capable of dealing with whatever issue presents itself. As a result, I think it’s fair to say Renogy managed to cover most of the aspects a buyer would be looking for in these devices.

The price tag doesn’t hurt the device’s case, either. It should fall right into the range of any realistic budget for a PWM solar charge controller. I wouldn’t have any issues spending this amount of money on the production and versatility offered by this device.

But I was sad to see some customers reported longevity concerns with the device. It seems the product tends to break down after a few years of usage. If you’re looking for an extra long-term option, these concerns might steer you elsewhere.

Solar Charge Controller for RV Buyer’s Guide

Buying an RV solar charge controller can be a hectic process, which requires a lot more thought than people might imagine. In fact, several crucial factors will play a significant role in determining what one suits your needs perfectly.

I’ll discuss these factors below to ensure a customer knows what the best solar charge controllers should look like and offer. As a result, picking the right choice will become a much more relaxed and simple task.

Charge Controller’s Amp Rating

One of the first factors to consider would be each product’s amp rating. This aspect comes into play because it’ll tell the highest amps can be outputted toward your batteries. For example, a person with 100-watt solar panels containing six amps of power wouldn’t want a 10-amp charge controller.

This situation would end up requiring an amperage need, which the charge controller couldn’t meet. In other words, your two 6-amp solar panels would create 12 amps, and the controller would only utilize 10.

It ends up being a waste, which isn’t what any rig owner will want. I’d suggest buying a solar controller with an amp rating 25% higher than your solar panel’s max power to avoid this issue.

This 25% wiggle room will help prepare for when solar panels produce more energy than the expected output. It tends to happen a lot more than people think during their RVing trips. You’ll want to have all the tools necessary to take advantage of it. Plus, this extra 25% will let you add additional solar panels down the road.

On/Off Button or Switch

Some charge controllers won’t come with one of the most convenient features available: an on/off button or switch. It might sound like a necessary design aspect, but a few options won’t come with them. If you’re anything like me, I’d suggest avoiding these products like the plague.

The reason behind it being essential is simple to understand. An on/off switch allows you to shut the device without removing the fuse at the battery. Therefore, this feature makes using the product much easier for an RV owner.

It ends up being an aspect that nobody should overlook during this process. So please, make sure your chosen RV solar charge controller has one before buying. It won’t be a decision any rig owner will find themselves regretting.

Another factor worth considering would be each product’s adjustability. Honestly, I’d recommend ensuring your chosen product has a feature called an adjustable charging voltage set point. It’ll allow a user to tinker with voltage during the panel’s charging process hinging on battery type: gel, AGM, or flooded lead-acid.

Rig owners who find themselves confused about the right voltage should contact the manufacturer for further information on their battery. These companies will have no issues providing the info needed to make the perfect adjustment.

In any case, the inclusion of an adjustable changing voltage setpoint will make the charging process easier and more efficient. Every single top-tier option will likely have this feature in its repertoire.

Does It Have a Dry Camp/Shore Power Switch?

Any rig owner would be wise to look for an option containing a dry camp/shore power switch. It’ll allow you to change your battery’s charge setpoint between standby mode and max power. As a result, you’ll be able to maximize the charging process’s efficiency.

Rig owners should switch to max power when adventuring away from an RV park or campground. Basically, max power would be the right choice whenever you’re apart from a shore power source.

If you’re using shore power, you’d be better off going with standby mode. This mode will also be useful when storing your rig for long periods by maintaining your batteries. Given this info, you can see why this feature is considered a must for any top-flight option.

Durability will always play a role in buying devices like a solar charge controller. You’re going to want an option capable of providing excellent results for many years. Due to this, buyers should examine what materials went into making their chosen model.

I’d suggest reading both the product description and customer reviews for each product to determine their durability. These resources should provide everything you need to decide whether it’ll hold up for the long haul.

What About a Battery Temperature Sensor?

Most high-quality charge controllers will have designs, which include a battery temperature sensor. What does this aspect do? It’ll make sure your batteries won’t ever become over or undercharged to ensure peak efficiency.

Battery temperature sensors will provide this by examining your battery’s temperature and adjusting the charging setpoint accordingly. This action ensures problematic issues, such as excessive water loss or plate sulfation, don’t rear their ugly heads.

In other words, a battery temperature sensor will be another feature working to keep your batteries in good condition. It also doesn’t hurt that this aspect will ensure your batteries always remain at the perfect charging level.

Each product’s price tag will play a role in your final choice as well. Some of these solar charge controllers can be rather costly, which makes having a well-constructed budget a necessity. It’s essential to think about what you want from one and determine acceptable budget ranges based on your wants.

For instance, someone who wants to buy an option with a battery temperature sensor will need to pay extra. Your budget should reflect this increase to ensure it remains realistic. This tool can make the entire process more manageable by limiting your choices.

You should then have a much easier time wading through all the options available. After all, the budget will make sure you’re picking from choices catered to your needs. It’ll make for a more effective buying process.

Solar Charge Controller FAQs

Our FAQ section will attempt to cover and answer any remaining questions within your mind. It should be the last resource needed to make a responsible decision during this process. After reading this section, the right choice should be rather clear.

Who is this for?

The first thing to know about a solar charge controller is these devices function as your RV solar system’s heart. It’ll ensure everything within these systems works correctly and productively. It’s capable of fitting into this role because it regulates voltage and current coming from your solar panels.

In doing so, these charge controllers will prevent your batteries from becoming overcharged. If you don’t have one, your batteries won’t charge correctly and might end up damaged. It’ll at least shorten their lifespan by a sizable margin.

This ability makes them a must-buy for anyone looking to use solar panels during their RVing trips. Of course, this statement doesn’t refer to people using smaller panels, which are considered trickle chargers.

Advantages and disadvantages of using an RV solar charge controller

One of the main issues with having an RV solar power system is dealing with unpredictable weather conditions. It’s a variable nobody but mother nature can control or predict, regardless of what some weatherman/weatherwoman says.

As a result, weather conditions cause solar energy to be somewhat unreliable. The power provided by it actually depends on many factors, such as season, location, time of day, etc.

These various factors will result in some periods where your rig’s solar panels can’t provide enough power to properly charge your battery. In other cases, the sun might be a little too powerful and offer an energy surge ensuring your panels work at maximum performance.

Both of these cases would cause an amount of solar energy problems, which could end up damaging your rig’s batteries or battery. For instance, a lack of energy could cause an ultra-low discharge that’ll shorten a battery’s lifespan.

On the other hand, an overwhelming amount of solar energy might cause your battery to overheat, excessively reducing its lifespan. These types of scenarios aren’t something a rig owner wants to deal with on their trips.

This issue is where having a solar charge controller comes in handy. It’ll be placed between your solar panels and battery to control the amount of energy your battery gets. Therefore, it’ll make sure the battery doesn’t have a low discharge rate or experience overheating.

You can now understand what benefits come from owning one of these devices. It’s an adequate way to make sure your rig’s solar energy system runs with a top-tier capability for a long time.

As for disadvantages, I can’t come up with a single reason why any solar energy RVer wouldn’t want or need one. But these products will be an additional cost rig owners have to account for in their respective budgets.

How to size your solar charge controller?

Many RVers assume selecting a solar charge controller’s size is complicated. Honestly, it seemed a little overwhelming when I first looked at these products. But the entire process only requires dividing your solar system’s wattage by the battery’s voltage.

The result will be the amps your solar charge controller needs to work effectively. You can then use this information to narrow down the available options significantly.

So let’s say you have a 12-volt battery and an 800-watt solar system onboard your rig. Sadly, this setup needs a 66.7 amp solar charge controller. I can imagine a little bit of panic just invaded your mind as it’s clear that no manufacturer makes a 66.7 amp model.

What does a person who finds themselves in this situation? It’s a simple matter of rounding up the amperage. You’ll want to choose a 70 amp or even 80 amp model with excellent solar charge controller reviews.

A perfect fit would be Outback Flexmax’s 80 AMP Solar Charge Controller. This top solar charge controller will be more than capable of meeting our needs. Furthermore, it allows some wiggle room to expand our solar array down the road.

Do you always need a solar charge controller?

It depends on your particular situation. In fact, determining whether you need a solar charge controller will rely solely on your panel’s output. The easiest way to figure it out is by dividing your battery’s AH capacity by the panel’s max amp rating.

Finding these two pieces of information should be easy. The amp-hour capacity rating is usually written on your battery’s exterior or on top of it. Meanwhile, the panel max amp rating will be found on its packaging or within its manual.

If you divide these two numbers and the total is over 200, a charge controller for lithium ion battery or another battery type isn’t needed. But RV owners don’t often find themselves in this situation.

Instead, they often get a total below 200, so a charge controller is necessary for their solar system.

Another way to make this process easy is by following this simple guideline: any panel that puts out 4 watts or fewer for every 100 battery AH won’t need one.

Can you use more than one charge controller?

RV owners can use more than one charge controller within certain situations. Of course, this issue will arise when people are looking to expand their rig’s solar system.

It often makes them freak out when they realize their budget solar charge controller can’t handle the system’s output anymore.

So rig owners must purchase one or two more controllers to meet their needs. They also have to ensure the new devices are the same types of solar charge controllers as the old one. Otherwise, it could cause performance issues that nobody wants their solar system to experience.

But don’t settle for the cheapest or a DIY solar charger controller. Your additional models also need to be high-quality choices. It’s the only way to ensure your solar system ends up meeting your high expectations.

How big of a solar charge controller do I need?

RV owners tend to get a little bent out of shape when deciding what size solar charge controller is needed for their situation. But I promise the process of figuring it out isn’t as complex as you might expect. Honestly, it ends up being rather easy to figure out with the right guidance.

The first thing to know is these controllers are rated based on two factors, your solar array’s current (amps) and the voltage of your rig’s solar system. Due to this, buyers will need an option that’s large enough to handle the power and current provided by your solar energy system.

In most cases, buyers will need a controller with one of the following volt ratings: 12, 24, and 48. But it’s essential to note there are devices available with volt ratings ranging all the way from 6 volts to 60 bolts.

Likewise, their amperage ratings will range between 1-amp and 60 amps. This amount of variation is where people tend to get more confused than necessary. After all, it’s a large variety of choices to choose from for a consumer.

But again, there’s no need to worry as figuring out what’s right for you isn’t tricky. For instance, a rig owner with an RV solar system containing 14-amp and 12-volt ratings will require a charge controller with at least 14 amps.

You’ll also need to factor in other factors: light reflection, sporadic increase current levels appearing, etc. But you can deal with this issue by buying a model with an amp rating of at least 25% higher than what your solar system contains.

As a result, a 14-amp system would require a charge controller of at least 17.5 amps. I’d suggest buying a 12V model with a 20-amp rating to run your system. After all, you’ll need to round up a bit because no manufacturer will make a 17.5-amp device.

But doesn’t this extra amperage hurt your solar system? It doesn’t, as experts will often suggest buying one with more than a few additional amps. This action will let you add more solar panels without issue.

Which is better, PWM or MPPT?

You’ve likely come across these two acronyms during your search, PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking). We used them to separate charge controllers into two types.

As you might expect, each type has situations where they would be more effective options than the other. I’m going to discuss both kinds below to ensure you know what fits your situation best.

PWM (Pulse Width Modulation)

PWM solar charge controllers are considered the older models within this market. Due to this, these devices are often much cheaper than MPPT models. These controllers work by regulating both the voltage and current flowing from your solar panel into the rig’s battery.

This PWM charge controller will then determine the amount of current your battery needs based on its voltage size. Once this voltage reaches the battery, it’ll separate from the panel and maintain your battery at the required voltage point.

Aside from a useful working process, these devices are known for reducing the risk of overcharging. But these products do have one large flaw when compared to MPPT options. They can only provide enough solar energy to reach a battery’s voltage requirement.

This flaw results in any energy produced over the requirement being wasted. PWM models end up not being the most efficient due to this issue. Buyers should only consider these devices when they want something simple and don’t have a lot of money to spend.

MPPT (Maximum Power Point Tracking)

As I previously mentioned, MPPT models are considered the more advanced type of solar charge controllers. This status comes from them being much more efficient than their PWM rivals. But explaining how they work is a little more difficult.

The first thing to know is your solar panels will produce more voltage on those gorgeous sunny days than your battery can handle. MPPT models are designed to deal with this issue by converting this extra voltage into additional current.

These devices will then utilize this additional current at a lower voltage, without losing any power. As a result, a rig owner can use their solar panel’s max power to charge a battery much more productively.

It’s also essential to note MPPT options are more capable and better suited for dealing with solar systems with higher voltages. You’ll want to buy this type when your voltage ratings on your solar panels and battery don’t match as well. PWM devices won’t work in this particular situation.

But one flaw does come with these all excellent benefits. The price tags on these devices are far more costly than PWM models. This issue makes it pivotal to think about how much you intend to use solar power during your trip.

If you plan on using it regularly, I don’t see how anyone could think it’d be wise to buy anything other than an MPPT option. Short-term solar power users would do better off with PWM devices, which won’t cause a massive dent in their bank account.

How many watts can a 30 amp charge controller handle?

It’ll depend on what model a customer ends up buying. In most cases, you can expect the max watt input of a 30-amp controller to be anywhere between 450 watts and 600 watts. Please ensure to check each product’s description for this aspect before making a final purchase.

How to install?

The installation process will vary from controller to controller. People might need to mount them alongside the solar panel, inside the rig with your battery, or outside their RV with the battery. Some may even need to install it as a different component located away from the panels and battery, but still connected to them.

In any case, the transmission losses should be minimized in a stand-alone system like an RV. This benefit comes from the generation of your rig’s panels being limited to electricity consumption provided by the load connected.

I would also suggest keeping the charge controller away from any heat generating equipment or moving parts. After all, this device is one of the essential parts of your RV’s solar system. It’s best to keep potential issues to a minimum.

Overall, a solar charge controller’s design will ultimately depend on your rig’s interior design and architecture. These aspects have a massive impact on the location and commissioning of a rig’s solar system and its parts.

How to use?

Solar charge controllers are considered the “brain” of your rig’s solar system. It’ll work in conjunction with the other parts to generate electricity for the rig by managing your battery’s discharge and recharge processes.

In particular, these devices will regulate and track the voltage and current, depending on your battery’s requirement. But the actual using process will depend on your chosen model. Some of these models come with an easy-to-use interface, containing buttons that control the adjustment process.

You’ll also encounter options with Bluetooth capabilities, which allow you to control everything from your phone. The using process does really change from product to product.

Any care and maintenance tips?

Taking care of a solar charge controller doesn’t take much work. It’s a simple process of checking its wire connections once a year and making sure they’re clean/secure. Outside of this task, there isn’t much to it.

Conclusion

You’ve now gained everything needed to make a Smart, responsible choice about what’s the best solar charge controller for RV. At this point, it becomes an exercise of utilizing what you’ve learned and applying during your search.

Finding the right one should become rather easy from there. But if a question or two pops up, don’t hesitate to let me know in our comment section. I’ll make sure to answer your post as quickly as possible. Thanks for reading!