How To Charge Lithium Iron Phosphate (LiFePO4) Batteries
If you’ve recently purchased or are researching lithium iron phosphate batteries (referred to lithium or LiFePO4 in this blog), you know they provide more cycles, an even distribution of power delivery, and weigh less than a comparable sealed lead acid (SLA) battery. Did you know they can also charge four times faster than SLA? But exactly how do you charge a lithium battery, anyway?
Power Sonic recommends you select a charger designed for the chemistry of your battery. This means we recommend using a lithium charger, like the LiFe Charger Series from Power Sonic, when charging lithium batteries.
CAN A LEAD ACID CHARGER CHARGE A LITHIUM BATTERY?
As you will learn in this blog, there are many similarities in the charging profiles of SLA and lithium. However, extra caution should be exercised when using SLA chargers to charge lithium batteries as they can damage, under charge, or reduce the capacity of the lithium battery over time. There are many differences when comparing lithium and SLA batteries.
SEALED LEAD ACID (SLA) BATTERY CHARGING PROFILE
Let’s go back to the basics of how to charge a sealed lead acid battery. The most common charging method is a three-stage approach: the initial charge (constant current), the saturation topping charge (constant voltage), and the float charge.
In Stage 1, as shown above, the current is limited to avoid damage to the battery. The rate of change in voltage continually changes during Stage 1 eventually beginning to plateau when the full charge voltage limit is approached. The constant current/Stage 1 portion of the charge is crucial before moving onto the next stage. Stage 1 charging is typically done at 10%-30% (0.1C to 0.3C) current of the capacity rating of the battery or less.
Stage 2, constant voltage, begins when the voltage reaches the voltage limit (14.7V for fast charging SLA batteries, 14.4V for most others). During this stage, the current draw gradually decreases as the topping charge of the battery continues. This stage terminates when the current falls below 5% of the battery’s rated capacity. The last stage, the float charge, is necessary to keep the battery from self-discharging and losing capacity.
Stage 3 is used if the battery is being used in a standby application, the float charge is necessary to ensure the battery is at full capacity when the battery is called upon to discharge. In an application where the battery is in storage, float charging keeps the SLA battery at 100% State of Charge (SOC), which is necessary to prevent sulfating of the battery that therefore prevents damage to the plates of the battery.
LIFEPO4 BATTERY CHARGING PROFILE
A LiFePO4 battery uses the same constant current and constant voltage stages as the SLA battery. Even though these two stages are similar and perform the same function, the advantage of the LiFePO4 battery is that the rate of charge can be much higher, making the charge time much faster.
Stage 1 battery charging is typically done at 30%-100% (0.3C to 1.0C) current of the capacity rating of the battery. Stage 1 of the SLA chart above takes four hours to complete. The Stage 1 of a lithium battery can take as little as one hour to complete, making a lithium battery available for use four times faster than SLA. Shown in the chart above, the Lithium battery is charged at only 0.5C and still charges almost 3 times as fast! As shown in the chart above, the Lithium battery is charged at only 0.5C and still charges almost 3 times as fast!
Stage 2 is necessary in both chemistries to bring the battery to 100% SOC. The SLA battery takes 6 hours to complete Stage 2, whereas the lithium battery can take as little as 15 minutes. Overall, the lithium battery charges in four hours, and the SLA battery typically takes 10. In cyclic applications, the charge time is very critical. A lithium battery can be charged and discharged several times a day, whereas a lead acid battery can only be fully cycled once a day.
Where they become different in charging profiles is Stage 3. A lithium battery does not need a float charge like lead acid. In long-term storage applications, a lithium battery should not be stored at 100% SOC, and therefore can be maintained with a full cycle (charged and discharged) once every 6 – 12 months and then storage charged to only 50% SoC.
In standby applications, since the self-discharge rate of lithium is so low, the lithium battery will deliver close to full capacity even if it has not been charged for 6 – 12 months. For longer periods of time, a charge system that provides a topping charge based on voltage is recommended. This is especially important with our Bluetooth batteries where the Bluetooth module draws a very small current from the battery even when not in use.
LITHIUM BATTERY CHARGING CHARACTERISTICS
Voltage and current settings during charging
The full charge open-circuit voltage (OCV) of a 12V SLA battery is nominally 13.1 and the full charge OCV of a 12V lithium battery is around 13.6. A battery will only sustain damage if the charging voltage applied is significantly higher than the full charge voltage of the battery.
This means an SLA battery should be kept below 14.7V for Stage 2 charging and below 15V for lithium. Float charging is only required for an SLA battery, recommended around 13.8V. Based on this, a charge voltage range between 13.8V and 14.7V is sufficient to charge any battery without causing damage. When selecting a charger for either chemistry, it is important to chose one that will stay between the limits listed above.
Chargers are selected to match the capacity of the battery to be charged, since the current used during charging is based on the capacity rating of the battery. A lithium battery can be charged as fast as 1C, whereas a lead acid battery should be kept below 0.3C. This means a 10AH lithium battery can typically be charged at 10A while a 10AH lead acid battery can be charged at 3A.
The charge cut-off current is 5% of the capacity, so the cutoff for both batteries would be 0.5A. Typically, the terminal current setting is determined by the charger.
Universal chargers will typically have a function to select the chemistry. This function chooses the optimal voltage charging range, and determines when the battery is fully charged. If it is charging a lithium battery, the charger should shut off automatically. If it is charging an SLA battery, it should switch to a float charge.
Lithium batteries replacing sealed lead acid in float applications
It is very common for lithium batteries to be placed in an application where an SLA battery used to be maintained on a float charge, such as a UPS system. There has been some concern, whether this is safe for lithium batteries. It is generally acceptable to use a standard constant voltage SLA charger with our lithium batteries, as long as it adheres to certain standards.
If using a constant voltage SLA charger, the charger must meet the following conditions:– Charger must not contain a de-sulfating setting– Fast/Bulk charge voltage of 14.7V– Recommended float charge voltage of 13.8V
As a side note, some Smart or multi-stage SLA chargers have a feature that detects open circuit voltage (As a side note, some Smart or multi-stage SLA chargers have a feature that detects open circuit voltage (OCV). An over-discharged lithium battery that is in protection mode will have an OCV of near 0V. This type of charger would assume this battery is dead and would not try to charge it. A charger with a lithium setting will try to recover or “wake up” an over-discharged lithium battery that is in protection mode.
Long term storage
If you need to keep your batteries in storage for an extended period, there are a few things to consider as the storage requirements are different for SLA and lithium batteries. There are two main reasons that storing an SLA versus a Lithium battery is different.
The first reason is that the chemistry of the battery determines the optimal SOC for storage. For an SLA battery, you want to store it as close to possible as 100% SOC to avoid sulfating, which causes a buildup of sulfate crystals on the plates. The buildup of sulfate crystals will diminish the capacity of the battery.
For a lithium battery the structure of the positive terminal becomes unstable when depleted of electrons for long periods of time. The instability of the positive terminal can lead to permanent capacity loss. For this reason, a lithium battery should be stored near 50% SOC, which equally distributes the electrons on the positive and negative terminals. For detailed recommendations on long term Lithium storage, check out this guide regarding storage of Lithium batteries.
The second influence on storage is the self-discharge rate. The high self-discharge rate of the SLA battery means that you should put it on a float charge or a trickle charge to maintain it as close as possible to 100% SOC to avoid permanent capacity loss. For a lithium battery, which has a much lower discharge rate and doesn’t need to be at 100% SOC, you may be able to get away with minimal maintenance charging.
Recommended battery chargers
It is always important to match your charger to deliver the correct current and voltage for the battery you are charging. For example, you wouldn’t use a 24V charger to charge a 12V battery. It is also recommended that you use a charger matched to your battery chemistry, barring the notes from above on how to use an SLA charger with a lithium battery. Additionally, when charging a lithium battery with a normal SLA charger, you would want to ensure that the charger does not have a desulfation mode or a dead battery mode.
If you have any questions about an existing charger’s capability with one of our products, please give us a call or send us an email. We would be happy to assist you with your charging needs.
Deep Cycle Batteries
Solar batteries provide energy storage for solar, wind power, or other renewable energy systems. A solar battery is just a deep cycle battery.batteries for solar panels are designed for the prolonged, repeated, and deep charging/discharging cycles needed to store and distribute energy generated by intermittent renewable sources like solar panels. For this reason, car batteries cannot be used as solar power batteries.
Grid tied systems do not need batteries unless you want to maintain power during utility grid outages. But for off grid systems, deep cycle solar batteries are essential and will likely be providing 100% of your electricity. This makes correctly sizing a solar battery bank among the most important steps of off grid system design. watch our video below for more.
Find more information on deep cycle batteries below, on our blog, in our DIY Solar Resources Library, or by talking with our energy storage experts at 877-878-4060.
Lithium Battery Accessories
Rack Mounted Batteries
Flooded Lead Acid Batteries
Sealed Agm Batteries
Sealed Gel Cell Batteries
Battery Maintenance Tools
Solar batteries are an important part of any solar energy system, allowing the energy from the sun to be stored and used later. Charging solar batteries is not as complicated as it may seem, but there are certain things to consider before doing so. This post will provide an overview of how to charge a solar battery, types of solar batteries, how long solar batteries typically last, whether you can charge solar batteries without a charge controller, and how much they cost. Read more below to get started with solar battery storage.
How to charge a battery from solar panel?
If you want to access renewable energy after the sun goes down or during a power outage, you will need to invest in deep cycle batteries. Deep cycle batteries are specifically designed to provide reliable and efficient power in solar and other renewable energy systems, while car batteries are not.
Deep cycle batteries differ from car batteries in several ways. First, they are designed to discharge and recharge multiple times over long periods of time without being damaged. Car batteries, on the other hand, are meant to start a vehicle and then quickly recharge. When it comes to selecting a deep cycle battery for your renewable energy system, lithium batteries are a great choice. They offer several advantages over AGM (absorbed glass mat) batteries. Lithium batteries last longer, require less maintenance, and are better suited for high-temperature climates.
It is also important to make sure that the battery bank voltage matches the solar array voltage in your system, unless you plan to use an MPPT charge controller. An MPPT charge controller will allow you to use a higher voltage battery bank than your solar array, resulting in more efficiency and greater power production.
Overall, deep cycle batteries are an essential component of any renewable energy system. Selecting the right battery for your needs is key to getting the most out of your system. With proper selection and maintenance, you can ensure that your system will continue to provide reliable power for years to come.
How long do solar batteries last?
When properly cared for, solar batteries can last up to twenty years.Solar batteries are an important part of any solar energy system. Without them, energy generated by the solar panels would be wasted. However, understanding how long they will last is key to making sure you get the most out of your investment. Lithium-ion batteries are the most popular type of solar battery, and they are known for their longevity. This makes them a great choice for larger solar energy systems. Flooded lead acid batteries are also popular, but they tend to have a shorter lifespan. With proper care, they can last between five to ten years. Sealed lead acid batteries tend to have the shortest lifespan, typically lasting less than five years. It’s important to note that the lifespan of a solar battery is not just determined by its type. Factors like temperature, use cycles, and the quality of the battery itself all play a role in determining how long a solar battery will last. That’s why it’s important to buy good quality batteries and keep them at optimal temperatures for maximum lifespan. In addition, it’s important to make sure you have enough solar batteries for your energy needs. If you don’t have enough batteries, you won’t be able to store all the energy produced by your solar panels and will likely end up wasting energy. Finally, having a good battery maintenance plan in place is essential for keeping your solar batteries in top condition. Regularly checking and testing your batteries can help you detect any potential issues before they become serious problems.
By understanding how long solar batteries last, you can make sure you get the most out of your investment in a solar energy system. With proper care and maintenance, you can ensure your solar batteries last as long as possible and give you years of reliable energy storage.
Can you charge solar batteries without charge controller?
You should always use a charge controller when charging solar batteries. When it comes to charging solar batteries, there are many different types of solar charge controllers. The three primary types are 1- or 2-stage solar charge controllers, 3-stage and/or PWM solar charge controllers, and maximum power point tracking (MPPT) controllers. Charge controllers for electric vehicles and golf carts may also be used for charging solar batteries. The most commonly used charge controllers range from 4 to 60 amps of charging current, but newer MPPT controllers can achieve upwards of 80 amps. This makes them very efficient for large-scale solar arrays. Without a solar charge controller, the battery may overcharge, reducing its lifespan and performance. For this reason, it is highly recommended that you use a solar charge controller to safely and efficiently charge your solar batteries.
How much do solar batteries cost?
Solar batteries are very affordable, with costs ranging from around 20 to over 5,000 depending on the capacity and the technology. It’s important to not just look at the cost per unit, but also the total cost of setting up a battery bank. This means taking into account any installation fees, additional hardware, and other costs. When looking at the cost of a solar battery, it’s also important to consider the cost per cycle. This is the cost of one full cycle of use. Depending on the technology and size of the battery, a cycle may last anywhere from hundreds to thousands of cycles. If you’re planning on using your solar battery for a long time, this cost-per-cycle should factor heavily into your decision-making. Taking all of these costs into account can give you a better understanding of the true value of a solar battery.
In this video you will learn how to correctly size a solar battery bank.
Solar Battery Bank Sizing Tips
We strongly recommend watching the solar battery bank sizing video above, but some of the key takeaways are:
- Connecting batteries in series (positive terminal of one battery to negative terminal of the next) increases voltage but keeps amp-hour capacity the same.
- Connecting batteries in parallel (positive to positive, negative to negative) increases amp-hour capacity but keeps voltage the same.
- Limiting the number of parallel battery strings minimizes the problems from uneven charging/discharging between strings.
- Don’t use batteries of different voltages or ages in the same battery bank. In fact, using multiples of the same exact battery to create your bank is recommended.
- You can convert back and forth between a battery’s Ah and Wh (or kWh) by using the battery’s voltage since Watt-hours = Amp-hours x Volts.
- Caveats about that the energy storage capacity number you got from our kWh calculator:
- The number provided by the calculator is your daily energy use. A battery bank based on that number will only provide enough power for one “day of autonomy”. It’s a good idea to double or triple your battery bank’s capacity and consider incorporating a generator into the system to ensure you’ve got enough power for prolonged periods of no solar/wind power generation.
- The recommended Depth of Discharge (DoD) on the deep cycle battery model your bank uses must be accounted for. For example, many lead acid batteries recommend discharging no deeper than 50% to get the most cycles out of them. meaning you should plan to only ever use half their rated capacity. Pay close attention to recommended DoD when comparing battery options to use for your bank.
- Ambient temperature and the efficiency of the system’s inverter also affect how a solar battery bank should be sized.
- If you expect your daily kWh use to increase soon (electric vehicle purchase, more people living in the house, etc.), consider oversizing your battery bank. Expanding a deep cycle battery bank later can be done in some cases, but is generally not recommended.
After determining the capacity and voltage of your battery bank (12V, 24V, or 48V DC), you can start thinking about the specific deep cycle batteries that will make up the bank. Need help making those determinations? Call us at 877-878-4060 or request a free off-grid solar power system quote.
Types of Solar Batteries
A deep cycle solar battery is the only kind of battery that makes sense for a solar or wind system, but what about the different types of deep cycle batteries. lithium, flooded lead acid, AGM, and gel? Which kind is best?
While it’s true that each different cell chemistry has its pros and cons, it’s also true that lithium batteries are easily the best choice for most solar panel systems. Compared to all the other chemistries, lithium batteries are deeper discharging, longer-lasting, lighter weight, safer, and maintenance-free. Yes, they are more expensive up front than the other types, but in the long run, the cost per kWh cycle is the best metric to look at. and with both longer cycle life and deeper Depth of Discharge than the alternatives, the cost per kWh cycle you’ll get from a lithium solar battery bank is unbeatable. and you won’t have to replace them as often.
Adding Solar Batteries to a Grid Tied System
If your solar power system is connected to the grid, it will shut down during grid outages as a safety precaution for the workers who will be repairing the utility equipment. To keep a grid tied solar system online during a grid outage, you will need to add a battery bank and a second inverter to create what is known as a hybrid solar system.
This video explains the two main ways to add battery storage to an existing grid-tied solar system.
Adding batteries to a grid-tied solar system is becoming increasingly popular. especially in areas where the utility grid is unreliable due to excessive demand (rolling blackouts) or frequent extreme weather events. For a new hybrid solar system or to retrofit an existing grid-tied system with battery storage, use our battery backup power system quote.
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How to Charge a 12V Battery Using Solar Panels?
Whether camping off-grid in your motorhome or enjoying the open seas on your boat, you probably can’t do without a 12V battery. Heading off-grid for any substantial period while still having enough electricity to run your essential devices means you’ll need a backup power source to recharge your motorhome, van, or boat battery.
In the past, you would need access to shore power to recharge your 12V battery. Now you can stay off-grid and recharge your battery with solar panels.
However, recharging a 12V battery with photovoltaic (PV) panels is more complicated than simply connecting the two. You’ll need all the right components and the know-how to optimise your solar panels for faster charging.
This guide will show you how to use solar panels to keep your 12V battery charged — no matter how long you’re off-grid or offshore.
What Size Solar Panel Do You Need to Charge a 12V Battery?
There are many different sizes and rated power outputs of PV solar panels, most of which are compatible with a 12V battery. The right size for you primarily depends on whether your panels match the battery’s amp hours, wattage, and voltage requirements, in addition to your energy consumption.
12V batteries come in various capacities from 5 to 200 amp-hours. Ask yourself the following questions before deciding which is the right size panel to charge your 12V battery:
- What’s the battery capacity in amp-hour (Ah) rating?
- How fast do you need the battery charged?
Let’s say you own a 12V battery with a 100 Ah capacity. Also, imagine you’re comfortable with a ten-hour charge time.
You’ll first need to convert the battery’s amp hours to determine the total wattage needed. The equation is as follows:
Amp-hours (Ah) x Volts (V) = Watts (Wh)
Keeping with the example above, the formula would look like this:
If you need your battery to recharge fully in 10 hours, you can calculate the following:
Total wattage (Wh) / recharge time in peak sun hours (h) = watts for panel
Plug in the numbers above, and you get:
So, at a minimum, you’ll need a 120-watt rated panel to charge your 12V battery within ten hours.
Keep in mind that various other factors determine the panel’s recharge efficiency. For one, the greater the rated power of the solar panel, the faster you can charge your battery. For example, an EcoFlow 400W Rigid Solar Panel with a high conversion efficiency rating of 23% can recharge a 12V battery much faster than a traditional 100W panel.
Battery chemistry is also a significant factor. A lithium-ion battery is more efficient than a lead-acid one but requires higher panel wattage. All other factors being equal, you’d need a 120-watt solar panel for lead acid vs a 190-watt panel for a lithium battery.
The downside is that lead-acid batteries are less durable and have shorter lifespans. If your vehicle or boat is more than a decade old, chances are it uses a lead-acid battery — and you might want to consider an upgrade to a lithium-ion or LFP battery.
If you’re building your solar power system piece-by-piece, the charge controller you use to connect the solar panel to the battery also can make the charging process more or less efficient.
The two main types of charge controllers are Pulse Width Modulation (PWM) and Maximum Power Point Tracking (MPPT), with MPPT being considerably more efficient. If you have a lithium-ion battery and ten peak sun hours, you’d need a 160-watt solar panel with an MPPT charge controller vs a 190-watt panel with a PWM.
If you’re purchasing an all-in-one solar power system solution like EcoFlow’s DELTA series, all the necessary components are already included. You don’t have to worry about compatibility issues between components. Just connect the solar panels and plug and play.
How Many Solar Panels Do You Need to Charge a 12V Battery?
The number of solar panels needed depends on the rated power output of the panel itself. A standard EcoFlow 100W Flexible Solar Panel is enough to charge the most common 12V batteries and is easily affixed to a curved surface without requiring drilling.
If you want to recharge faster or require significant energy output, buy multiple solar panels to build a solar array. It’s also worth considering a modular power kit that can provide you with enough off-grid electricity to run anything you might need.
Components You Need to Charge a 12V Battery
Charging a 12V battery isn’t as simple as connecting the solar panels to the terminals. Directly charging a 12V battery with photovoltaic panels isn’t possible.
You’ll need the appropriate tools and components to connect the solar panels:
- 12V battery
- Solar panel(s)
- Solar charge controller (must be compatible with 12V batteries; PWM or MPPT)
- Battery cables
- Charge controller adapter cables
The charge controller regulates the electricity flow from the solar panels to the battery, protecting it from overcharging, which leads to permanent damage and can even be hazardous. Once the battery reaches full charge, the controller cuts off the DC energy supply, protecting it from potential harm.
In most cases, you’ll also want a solar power system with a solar battery to store excess power and an inverter to run devices and appliances that run on AC (household electricity).
How to Charge a 12V Battery with Solar Panels
Here’s a step-by-step guide on connecting your solar panels to charge a 12V battery:
Step 1: Connect the 12V Battery to Your Charge Controller
Check whether the 12V battery has wires. If not, you’ll need to purchase 10- or 16- gauge wires to connect them to the charge controller. Attach the stripped end of the positive battery wire to the position terminal and vice versa. Insert the bare wire ends into the charge controller ports and tighten them with a screwdriver.
Link the ring terminal of the positive battery wire to the positive terminal. Repeat the process for the negative battery cable.
Step 2: Connect Your Solar Panels to the Charge Controller
Attach the negative solar panel adapter cable to the negative solar panel cable. Do the same thing for the positive panel cable.
Plug the positive solar input cable into the positive solar PV terminal on the controller and tighten the terminal shut. Repeat this process for the negative input solar cable.
If you’re connecting multiple panels, which you can do with some systems like the EcoFlow Portable Solar Panels, you’ll need to use MC4 connectors to connect the panels in series.
Step 3: Check the Connection
Once the wires are connected, test the connection by turning on the battery and power system. The charge controller should turn on, indicating that the charge controller and battery are connected. Monitor your charge controller’s display screen and ensure it’s producing readings. If you see a zero or blank screen, you probably didn’t connect everything properly.
Checking the connection is even easier if you’re connecting your solar panels to a power station that you then use to charge the 12V battery. Portable power stations like the EcoFlow DELTA 2 have intelligent algorithms built into the MPPT to track the voltage and current rate in real time. With the dedicated EcoFlow app, you can monitor the voltage output and control the power station directly from your mobile device using an internet or BlueTooth connection. The built-in charge controller will keep you updated about the recharge time.
Step 4: Position the Solar Panels Under Direct Sunlight
Lastly, you’ll want to set up your solar panels with optimal orientation for the best light exposure. You can either mount rigid solar panels on your vehicle or boat’s roof. If you have a portable solar panel, use the kickstand to position it on the ground or deck.
The solar panel size you need to keep a 12V battery charged largely depends on your specific batteries wattage, voltage, amp-hours — and, of course, your energy consumption. Once you know the specifics, setting up a functioning solar power system between your solar panel and 12V battery is simple, especially if you use a portable power station or solar generator with everything built in.
Now that you’ve read this guide, you should have a rock-solid system that can deliver off-grid power anytime and anywhere there’s sunlight. Whether you’re a homeowner, motorhome owner, or outdoor enthusiast looking for recreational power, a solar energy system can give you incredible freedom.
Shop EcoFlow today to discover all your options for energy independence.
EcoFlow is a portable power and renewable energy solutions company. Since its founding in 2017, EcoFlow has provided peace-of-mind power to customers in over 85 markets through its DELTA and RIVER product lines of portable power stations and eco-friendly accessories.
Solar Charge Controller Settings
A solar charge controller has various settings that need to be altered for it to function properly, such as voltage ampere settings. Today you will get to know about solar charge controller settings along with solar charge controller voltage settings.
Solar Charge Controller
The amount of power generated from the solar panel travels to the inverter batteries. This power needs to be maintained and regulated. A solar charge controller is used for this purpose. It sends short energy pulses to the battery. The average output produced by an MPPT solar charge controller can be 42 volts. You will require additional batteries to produce higher voltages. Here is the catch: to prevent your batteries from damage, you need to choose the right solar charge controller.
Solar Charge Controller Settings
Just installing a charge controller won’t solve all your problems. There are different settings that need to be checked and manually adjusted. Different types of batteries like Lithium Iron Phosphate (LIPO), lithium, iron phosphate, lead-acid, and Absorbent Glass Mat (AGM) batteries have different settings. However, there are only two types of charge controllers.
MPPT controller or maximum power-point tracking controller
PWM controller or pulse width modulation controller
Before starting to set up the solar charge controller, you need to understand its functioning of it. Here are the points that you need to keep a note of while installing and setting up the solar charge controller.
Once the battery is fully charged, the battery will not hold more solar energy in comparison to the chemical content.
- If the battery is charged high, it can result in the development of heat and gas inside the battery.
- Electrolytes inside the battery began to expand. This further led to the development of bubbles.
- This chemical process leads to the generation of hydrogen gas, which is explosive.
- An overcharged battery will decrease the capacity and increase the aging process of the battery.
Battery Floating Charging Voltage
The voltage at which a battery is maintained once it is fully charged is known as the battery floating charging voltage. This voltage maintains the capacity of the battery by self-discharging it. The typical voltage for a 12V system is 13.7V and for a 24 V system, it is 27.4V. 58.4V is the voltage for a 48V system.
Battery Over-Discharging Protection Voltage
It is also known as under voltage cutoff voltage and its value should also be in accordance with the battery type. In solar charge controller settings, the voltage value range for a 12V system is 10.8V to 11.4V. For a 24V system, it is 21.6V to 22.8V, and 43.2V to 45.6V for a 48 V system. So, the typical values are 11.1 V, 22.2 V, and 44.4 V.
Battery Overcharging Protection Voltage
This voltage value should be set as per the battery type. This voltage is also termed a fully charged cutoff voltage or over-voltage cutoff voltage. This voltage value for a 12-volt system ranges between 14.1 V and 14.5 V. For a 24-volt system, it is 28.2V to 29V and for a 48V system, it is 56.4V to 58V. So overall, the typical value for the voltage is 14.4V, 28.8V, and 57.6V.
Charge Controller Capacity
It is the maximum number of amperes that your solar charge controller can handle. It is the parameter on the basis of which a solar charge controller is rated. It can be 10A, 20A, 30A, 40A, 50A, 60A, 80A, or 100A.
Maximum Charging Current
It is the maximum output current of the solar panels or solar arrays. It is the output that you receive from the batteries.
It is also known as the Rated Operational Voltage of your solar power system which refers to the battery bank voltage (direct current operational voltage). Usually, the value is 12V, 24V, or 48V. However, a medium-scale or a large-scale charge controller system has voltage values of 110V and 220V.
Solar Charge Controller Voltage Settings
These are the most critical settings that need to be done carefully for the better functioning of the solar charge controller. A solar charge controller is capable of handling a variety of battery voltages ranging from 12 volts to 72 volts. As per the basic solar charge controller settings, it is capable of accommodating a maximum input voltage of 12 volts or 24 volts.
You need to set the voltage and current parameters before you start using the charge controller. This can be done by adjusting the voltage settings. Here is the list mentioning the most critical voltage settings for the solar charge controller.
- Absorption Duration: (Adaptive/Fixed)
- Absorption Voltage: 14.60 volts
- Automatic Equalization: (Disabled / Equalize every X Days) Disabled
- Equalization Current Percentage: 25%
- Equalization Duration: 4 hours
- Equalization stop mode: (Fixed Time / Automatic on Voltage) Fixed time
- Equalization Voltage: 14.40 volts
- Float Voltage: 13.50 volts
- Low-Temperature Cutoff (optional): Disabled
- Maximum Absorption Time: 6 hours to 3 minutes (max) per 100Ah battery capacity
- Maximum Absorption Rate: 30 minutes per 100Ah battery capacity
- Manual Equalization: Select start now
- Maximum Equalization Duration: 3-4 hours
- Re-Bulk Voltage offset: 0.1 volts
- Tail Current: 2.0A
- Temperature Compensation (mV/°C): 27.7 volts / 40° Celsius-25° Celsius
Note: Settings can be changed manually on the controller or from the PC Software. Follow the instructions of the manufacturer for the best results.
Steps in Solar Charge Controller Settings
While you set up your new solar charge controller, you should begin with properly wiring the controller to the battery bank and solar panels properly. Once the wiring is properly done and the controller detects the power, its screen will light up. Other steps are as follows:
Enter the settings menu by holding the menu button for a few seconds.
Charge current PV to Battery will be displayed
Battery Type Selection can be done by pressing the menu button for a long time.
The battery voltage will be auto-detected by the controller.
According to the user manual, set the setting for absorption charge voltage, low voltage cutoff value, float charge voltage, and low voltage recovery value.
If the system has an option for setting up the discharge value for DC, then set it as per the user manual.
Once the setting is done, the charge controller will instantly start the charging process.
PWM Solar Charge Controller User Manual
The user manual of a PWM or a pulse width modulation solar charge controller contains information regarding the following:
LCD Display or Key
A solar charge controller has a digital display that displays a number of things on the panel through abbreviations or signs and symbols. Here is the list of those things and what they mean.
- A panel with a small sun shining indicates the solar panel charge.
- An arrow near the panel when it is bold black means the system is on Aqualation or buck when the arrow is flicking it means it is on float mode.
- A square filled with horizontal bars indicates battery.
- Near the battery sign, there is an arrow indicating the output.
- A bulb sign indicates the load
- V% indicates the voltage
- AH is for ampere hours
- A square-shaped box indicates a menu. It is used for switching between different displays. You can enter or exit the setting by pressing it for a long time.
- An up arrow is used to increase the value
- A down arrow showing a decrease in the value
LCD Display or Setting
To browse different interfaces in the solar charge controller settings, press the menu button. The LCD or key display discussed in point 1 is the main display. Next displays in order when you press the menu are:
- FloatVoltage – The screen shows LIT, voltage, and the battery
- Discharge Reconnect – Shows LIT, voltage, battery, output (arrow), and load (bulb)
- Under voltage Protection – Displays LIT, voltage, empty battery symbol, and load (bulb)
- Work Mode – It displays hours (H), output (arrow), and load (bulb). OH, means dawn to dusk, 24H means load output is for 24 hours, and 1-23H means the load is on after sunset and closed after sunrise hours.
- Battery Type – LIT and the battery box with horizontal bars, determine the amount of battery charged and the type of battery. LIT is for lithium. After this, you are again on the main display.
Important: To switch On or Off the load manually on the main display, press the down key.
- 3-stage PWM charge management
- A built-in industrial microcontroller with adjustable parameters
- A pulse width modulation solar charge controller has the following features:
- Battery Switching functions between lithium and lead battery. The lithium battery is the default setting and switches it to the battery type interface by holding it for 3 seconds.
- Dual metal–oxide–semiconductor field-effect transistor (MOSFET) Reverse current protection with low heating dissipation
- In-built protection for short-circuit open circuits, overload, and reverse
Every electrical appliance comes with a list of safety instructions that are prepared according to the appliance. A PWM controller has the following safety instructions mentioned in its user manual.
- Do not connect another charging source with the charge controller. The controller is suitable only for regulating solar modules.
- For the controller to recognize the battery type, ensure the battery has enough voltage before you begin the installation process.
- Install the controller on a well-ventilated and flat surface. While running, the controller will be heated.
- This controller is suitable for lithium batteries. All kinds of lead batteries (open, AGM, and gel) are also compatible with it.
- To minimize loss, keep the battery cable as short as possible.
In solar charge controller settings, it contains instructions related to the connection. It tells you which port you need to connect to which wire.
- Connect the battery to the charge regulator (plus and minus)
- Connect the consumer to the charge regulator (plus and minus)
- Connect the photovoltaic module to the charge regulator (plus and minus)
This section contains all the information regarding the voltage, amperes, input, output, size, weight, etc. of the PWM solar charge controller.
- Batt voltage – 12 volts / 24 volts auto adapt.
- Charge current – 10A (KYZ 10), 20A (KYZ 20), 30A (KYZ 30)
- Discharge current – 10A (KYZ 10), 10A (KYZ 20), 10A (KYZ 30)
- Max solar input – less than 41 volts
- Model – (KYZ 10) (KYZ 20) (KYZ 30)
- Operating temperature –.35 ~60° Celsius
- Size or weight – 13370355 millimeters or 140 grams
- Standby current – greater than 10 mA
- USB output – 5 volts / 2 A Max
The technical parameters of lithium and lead batteries under certain parameters are mentioned in the table below.
|Type of Battery
|Lithium (LIT) battery
|12.0 volts (default, adjustable range 11.5-12.8 volts)
|10.7 volts (defaults, adjustable range 9.0-11.0volts)
|11.6 volts(defaults, adjustable range 11.0-11.7volts)
|Lead acid battery (bAt)
|13.7 Volts (defaults, adjustable range13-15V)
|10.7V (defaults, adjustable range9.0-11.0 Volts)
|11.6 Volts (defaults, adjustable range11.0-11.7V)
Every electronic appliance faces some problem that can be easily resolved with troubleshooting. The basic problem and its solution are mentioned under the troubleshooting column in the PWMM user manual. Here I have mentioned the problem – probable cause – solution.
- Charge icon not on when sunny – Solar panel is open or reversed – Reconnect
- Load icon off – Battery low – Recharge
- Load icon off – Mode setting wrong – Set again
- Load icon slow flashing – Overload – Reduce load watt
- Load icon slow flashing – Short circuit protection – Auto-reconnect
- Power off – Battery too low reverse – Check battery or connection
Solar Charge Controller 24V Settings
After the solar charge controller settings for a 12V system, the 24V system is the most common charge controller used in residential solar power systems. The basic settings for this are mentioned in the user manual of your charge controller. However, here are a few basic settings that are for a 24V system.
- Battery Floating Charging Voltage is 27.4V
- Battery Over-discharging Protection Voltage is 21.6V to 22.8V
- Battery Overcharging Protection Voltage is 28.2V to 29V
- Solar charge controller settings for AGM battery
The solar charge controller setting for an AGM or Absorbent Glass Mat battery is also for 12 volts, 24 volts, or 48 volts. The maximum charge current should be at 50A maximum per 100Ah battery capacity. The absorption voltage should be 14.60 volts and the float voltage at 13.50 volts. Equalization voltage at 14.40 volts and bulk voltage offset at 0.10 volts. Absorption duration should be adaptive, and duration should be between 6 hours to 30 minutes per 100Ah battery capacity. The current percentage for equalization is at 25% and its duration at 4 hours max.
Solar Charge Controller Settings for Lithium Batteries
Before you begin setting up your lithium batteries, remember that lithium batteries do not require temperature compensation. Also, if you are replacing lead batteries with lithium batteries and the settings are set at Equalized this needs to be changed. To change this, select, EQE (Master equalizer enable/disable) on the charge controller display. This can also be done by selecting OFF the dip switch in other controllers. Some common settings for a multi-stage charge profile need to be set to the following settings:
- Charge voltage – 14.4 volts (3.6 VPC)
- Absorption time – 30 minutes to balance lithium cells
- Float voltage – 13.6 volts
- Resting voltage (default) – 3.4 VPC
Solar Charge Controller Settings for Lead Acid Battery
The lead acid battery is a classic configuration in a solar power system. Once you convert the battery type from lithium/AGM to lead acid battery, the original set parameters for a lead acid battery will be used. These configurations are already installed in the charge controller system. And sometimes, it is just plugging and using the system.
Well, today you learned about the alteration in solar charge controller settings in accordance with the type of batteries your inverter has. Also, solar charge controller voltage settings should be carefully done to get the maximum potential output from the solar charge controller.
Olivia is committed to green energy and works to help ensure our planet’s long-term habitability. She takes part in environmental conservation by recycling and avoiding single-use plastic.
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2 Комментарии и мнения владельцев
Hello, very nice article! Could I have 2 questions: 1.) I have the same type controller. Do you know, why my solar controller is changing battery setup from B03 to B01 by itself? Is it damaged? 2.) Now I miss arrow on display between solar panel and battery. Does it mean, that battery is fully charged? Thank you.
Dear Jaro, Thankyou for reaching out to us. For Query 1: Solar Charge Controller changing battery setup from B03 to B01. We have found that said settings mean as follows: B03 – Battery Over Voltage – This error occurs when Input voltage to battery terminals exceeds 17.5-V B01 – Battery Disconnected – This fault code appears when the Portable solar kit cannot detect a battery bank. The issue you are facing can be due to the following reasons: 1- Automatic Configuration – Some controllers adjust their settings based on the battery type and conditions they detect. Check your controller’s manual to see if it has this feature and disable it, according to instrcutions listed in the manual. 2- Firmware or Software Issue: Glitches in the controller’s firmware or software can cause unexpected behavior. Check for firmware updates or try resetting the controller to its factory settings. If this doesnt work, contact the manufacturer to get the controller checked for damage and for possible repair. For Query 2: Arrow on Display between Solar Panel and Battery It is difficult to determine the exact meaning without knowing your controller’s model. 1- In some cases, the arrow indicates charging. 2- It could also mean the battery is fully charged. 3- Or, there might be an issue the controller requires a reset. Follow steps listed in the manual to do the same. And if the issue is still unresolved, there could be some issues with wiring between the 3 components. Last option is to get the entire system checked by an authorized technician and contact the manufacturer for assistance.
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