Nekteck 20w solar charger. Goal Zero Nomad 14 Plus

Best portable solar chargers

We reviewed 25 products and spent over 100 hours scientifically field testing the top 15 portable solar panels to find the best ones for modern survival. After considering price, durability, performance, size, and weight, we recommend the Ryno Tuff 21W Portable Solar Charger.

March 10, 2022 : The Goal Zero Nomad 7 Plus, Goal Zero Nomad 14 Plus, Renogy Portable E.Flex 10W, iClever USB Solar Charger, and X-DRAGON 14W have been discontinued
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Being prepared for emergencies means being able to generate electricity without the grid. There are bigger solar panels for your home and basecamp, but many preppers want to charge their portable batteries and USB-powered devices (e.g. phones) while on foot. These portable solar panels, which are typically marketed for backpacking, hiking, or camping, are a core part of many people’s go-bags and car kits.

Portable solar chargers pair well with a rechargeable battery pack (either a single Li-Ion pack or a charger for AA-style batteries), and some of them even come with a built-in battery pack.

Despite how simple these USB solar chargers appear — you put them in the sun and plug your gear into them, right? — there’s a lot more to picking the right charger and learning how to use it effectively than you might imagine.

Check out the beginner’s guide to off-grid power for the basics in simple terms and what kind of gear you need for your goals.

Bigger panels always perform better. Get the biggest you can within your space, weight, and budget limits.
Time of day doesn’t matter nearly as much as placing the panels perpendicular to the sun.
Despite what you might read in guides, it appears to be very rare for panels to not go back up to full power after a Cloud passes overhead. This may have been an issue for older panels, but it seems to have been fixed in the current generation.
Heat decreases panel performance, so keep your panels off of hot surfaces like stone or metal. Some of the panels that heated up quite a bit had Rapid voltage and current oscillations, and these wild swings lowered the total overall energy output over the course of a test run.
Avoid charging your phone/headlamp/whatever directly from a solar panel in the hot sun. Rather, charge a battery pack first, then use that pack to charge your phone.

Read below the fold for deep details on our testing methods and data, tips on getting the most from your panel, and more.

Best for most people:

Ryno Tuff 21W USB Solar Charger

This fairly-priced and high-power charger is not exactly compact at 1 pound and 1 square meter of panel surface area, but it’s thin and light enough to be fine in a typical pack.

The best portable solar panel for most people is the Ryno Tuff 21W. After hours of testing with a load tester and a multimeter, this charger ranked at or near the top of our review in the key areas of power output, watts per ounce, and efficiency. As we measured weather, sunlight levels, and panel heat in a variety of conditions, the Ryno Tuff was able to maintain an impressive 10W on a single USB port. In fact, we even got it all the way up to 12W for a bit on one test run. The price is also right — often coming in 5-10 cheaper than the competition — to the point that not only is it the overall winner but it’s the best budget option as well.

As of June 2022, customer service seems to be non-existent for Ryno Tuff. It is a quality panel and is still being sold by reputable sellers, but do not expect any sort of warranty or customer service.

We strongly recommend pairing a solar charger with a separate external USB battery bank so that you don’t have to ruin your gadgets built-in batteries by baking them in the sun during a charge cycle. Many of the products in this guide sell versions with and without a battery built into the solar charger. Although we prefer keeping the charger and battery separate, it’s not wrong if you pick the built-in battery version.

CHOETECH 19W USB Solar Charger

A very close second place, this panel is slightly more compact than the Ryno Tuff competitor at 0.9 square meters of total PV area. Slightly larger but 40% heavier than the Renogy.

The CHOETECH 19W is a great alternative — if you can find the CHOETECH for about the same price as the Ryno Tuff, confidently grab whichever one you’d like. The CHOETECH weighs the same as the Ryno Tuff yet folds into a slightly more compact design that saves precious space in smaller bags. The build quality is solid, just like the Ryno, but we did like the CHOETECHs embedded metal rings more than the cloth loops on the Ryno. This panel produced slightly less peak power than the Ryno in most of our testing, but the overall performance is close enough in most conditions.

Advertised numbers don’t reflect reality

Our testing shows that real-world performance almost never reaches what the companies claim. At best, you should use those numbers to understand relative differences between products. If you have specific numbers you need to hit, such as watts or amps, assume there’s at least a 25-50% drop off from the marketing data.

Most USB chargers have names like RAVPower 16W, with the 16W label referring to the amount of power in watts. But manufacturer-provided power ratings are generated under highly artificial test conditions in order to promote the highest number possible.

It’s better to use those advertised wattage numbers as a rough indication of general panel size and relative power performance — e.g. a panel labeled 20W is probably a bit stronger and bigger than one labeled as 10W, even though neither panel will hit their advertised numbers.

Similarly, we found the amps coming out of a USB port almost never reached the rated maximum. For example, one panel that advertised 2.4 amps of USB output actually never got above 1.8.

Power output greatly depends on angle to the sun

Our testing found that how the panel is angled relative to the sun matters a lot more than simply the time of day. A panel at a bad angle at high Noon will perform worse than the same panel pointed directly at the sun at 6 PM. Even a few degrees off of 90/perpendicular makes a noticeable difference.

Some of these chargers hit maximum output even as late as 7 PM — just through proper positioning.

You know all those marketing pictures where the panel is strapped to the back of a hiker’s pack, using the attached loops that are helpfully built into the panels for that express purpose?

This will only work if the sun is directly behind you or you can get some portion of the panel on top of the bag. Vertical almost never works, especially if you keep changing the orientation of the panel to the sun.

You don’t have to baby the panel every few minutes, just be Smart about your positioning. Worst case: lay the panel flat through the mid-day hours.

To see how important the sun angle is in real wattage numbers, here’s a graph of an orientation test with the BigBlue 3 28W panel on a sunny, early September day at about noon.

We rotated the panel through a series of positions while making an audio recording of calling out the positions and timestamps so that we could mark them on the graph above. You’ll see that the sunlight level is constant at about 750W/m2, but the panel’s power output swings wildly with each position.

As we moved the panel from flat to 45 degrees from the sun, for example, the power output jumped from just under 12W to 14W. Turning the panel to 45 degrees facing away from the sun dropped the power output all the way down to two watts.

Top 3 Solar Phone Charger Examples

The following examples will be portable solar panel models that can be used to charge your phone directly or indirectly via an optional battery bank.

In several cases, you can buy these in a kit along with a battery bank, like the Goal Zero Venture 35 with Nomad 10 kit (affiliate link).

BigBlue 28W USB Solar Charger

The BigBlue 28W USB solar charger is one of the most suitable chargers for cell phones. It possesses four different foldable SunPower solar panels that are very compact.

Also, it has three 5V/2.4A (max) USB output ports for simultaneous device charging.

However, the panel is best used with a maximum of two USB ports simultaneously to get the full 5V/2.4A for both ports.

This means that the USB ports combine for a maximum of 24W of output (5V/4.8A), which is not 28W but is still a relatively high number for a portable solar charger.

According to reviews, the BigBlue 28W USB solar charger appears to deliver a good output in sunny and, surprisingly, cloudy conditions.

On the downside, the BigBlue is a long solar panel when unfolded (33 x 11 x 0.2 in). Hence, users need to remain conscious of their size when using it for backpacking needs.

Nekteck 21W Solar Charger

The Nekteck 21W solar phone charger has three solar panels and two standard USB-A ports.

Each port is capable of 5V/2.0A when one port is used, but when using both ports, the maximum amperage is 3.0A (15W max).

Like the BigBlue, the Nekteck outputs less power than the panel says in its listing. That being said, 15W is enough to power up a smartphone or multiple phones when needed.

Although it has less power than the BigBlue panel, it’s more compact with an unfolded length of 26.2 inches.

This may be easier for you to mount onto your backpack or tent as it is about seven inches shorter than the BigBlue.

Impressively, it is also a lightweight solar charger, weighing only 18 ounces in total.

Goal Zero Nomad 10 Solar Charger

The Nomad 10 is an impressive product from Goal Zero.

It comes with a foldable solar panel, which has a wide surface area.

It weighs 1.2 pounds, which makes it relatively heavy, but compact.

The 10W, 6-7V panel comes with a built-in USB-A port, which functions effectively.

I’ve used this panel to successfully charge my phone directly, but the best option is to use one of Goal Zero’s battery banks for charging up.

The Flip 12 or Venture 35 are some options that are smaller for portability.

The two downsides to this panel are its decreased power output compared to the previous two panels as well as its cost.

The Nomad 10 by itself costs almost double that of the BigBlue or Nekteck panels.

But its compact size makes it useable for almost any purpose (9.5 x 14.5 x 0.75 inches unfolded).

You can see how the Nomad 10 worked in my own testing to charge my Sherpa power bank in my video below.

You can speed up your solar charger by angling it perpendicular to the sun and charging one device at a time. A direct angle to the sun allows the charger to absorb as much sunlight as possible. Charging one device at a time avoids splitting the charger’s output power between multiple devices.

If the device is placed outside your backpack while moving, please note that it may not charge fast.

Since you are on the move, there’s a high probability that the panels aren’t always facing the sun resulting in inconsistent charging.

If you want a faster charge from the solar phone charger, you may also consider using shorter cables.

Please note that shorter cables don’t necessarily make the solar phone charger work faster. However, it helps in the overall charging speed due to a minimal amount of wasted energy.

Do Solar Phone Chargers Really Work?

Solar phone chargers really work as long as they’re exposed to quality sunlight. It’s essential to pick a solar charger with at least 10 watts of power. A 10W solar charger will recharge a typical cell phone in 1.3-1.6 hours. Any charger less than 10W may output too slow of a charge to your phone.

Solar phone chargers that are closer to 15 watts or higher can charge a mobile phone along with other devices simultaneously.

The portability of your solar phone charger matters a lot.

Hence, it is important to confirm the weight and dimensions (folded and unfolded) of any panel you intend to purchase.

If your solar phone charger has large folded solar panels, it may be too heavy to carry.

However, large folded solar panels may have higher efficiencies (charge devices faster) due to a wide surface area.

For example, my Elecaenta 120W solar panel is massive and weighs almost 12 pounds! But this is clearly too powerful of a panel for simply charging a phone in most scenarios.

Some solar phone chargers don’t function well compared to others, depending on their output.

Ensure that you pick a brand of solar charger that works efficiently and that has good and honest reviews.

If you ever come across issues with your solar charger, I have a guide to troubleshooting your panel to get it working again. I also have some maintenance tips to prevent you from running into any issues while using it off the grid.

Is There a Difference Between Rechargeable and Solar Batteries?

There is no difference between rechargeable and solar batteries. Solar batteries are used in storing chemical energy, which gets converted to electrical energy. Solar panels trap energy from the sun, and it gets stored in batteries for later use. Hence, solar batteries are rechargeable batteries.

In some cases, solar chargers don’t come with rechargeable batteries (or any battery at all), which is usually a challenge.

A significant example of a product that doesn’t come with a battery is the Nekteck 21W solar charger. Users will need to buy a separate battery pack to make it a power bank as well.

Rechargeable battery

Rechargeable batteries are electrical batteries that can be discharged and charged multiple times. However, they are produced in different shapes, sizes, and specifications.

There are lots of different combinations of electrolytes and electrode materials utilized. Examples are nickel-cadmium (Ni-Cd), lithium-ion (Li-Ion), nickel-metal hydride (Ni-MH), lithium-ion polymer (Li-Ion polymer), and lead-acid.

Li-ion batteries are very stable batteries with a low self-discharge rate but high energy density and voltage capacity. Besides, they are very durable batteries.

Li-ion batteries tend to last for eight or more years and have nearly zero memory effect. So, even if the are a little high, it is worth the investment.

Continue Reading:

Key Features Specs

Ultra lightweight: (18 oz)
Ultra compact: (6.3x 11.1x 1.06in folded or 26.3x 11.1in opened) design.
Power input: 21W High-efficiency Panel
Power output: 5V Standard USB port x 2
Output current: Up to 3A (2 USB port used simultaneously) up to 2A (1USB port used)

Nekteck 21W Solar Charger Tip On Charging

Another tip if you choose to get this Nekteck solar charger is to make sure the charging devices are not directing underneath the solar panels. Hopefully, with the sun shining directly on the solar cell, the area directly underneath can get hot, and batteries and phones stop charging when they get too hot.

Nothing more annoying than hiking all day in the sun, thinking your device has charged, only to realize in the camp that it has over-heated and refusing to charge. I would suggest running the USB cord from the panel to your device and carry the device in your shirt or pants Doing so will also give you quick access to check on the progress of the charge.

Should You Buy The The Nekteck 21W Solar Charger?

This solar panel set-up is a must-have for any hiker or camper spending time away from cultivation. They say for a portable solar charger to work, you need to collect at a minimum of 14W for it to charge at a timely rate. The Nekteck is 21W and charges fast if you know how to use it.

Don’t expect miracles; you can’t just plug in your iPhone and expect a super-fast charge like you would at home. If you have realistic expectations and the weather conditions are decent, you’ll get on fine with the Nekteck 21W Solar Charger. Finally, remember to use it to charge your power bank first rather than your phone or camera, as it works much more efficiently that way.

I really hope you found this review useful. I suggest also taking a look at our other guides such as the Best Gas Canister Camp Stoves, Best Shock-Aborbing Trekking Poles, and our guide of the Best Self-Inflating Camping Mats.

Will it charge when it’s cloudy?

Clouds have a similar effect to objects causing shading. They prevent as many photons from reaching your panel. Therefore, the same as in the shade, the solar power bank will still charge but at a much slower speed. Estimates and studies show this to be around 25% of direct sunlight on a moderately cloudy day and as little as 10% on a very cloudy day.

PEALIKER (10,000mAh) – 30 hours to fully charge in the sun
OUTXE (20,000mAh) – 50 – 70 hours full charge (recommend emergency use only)
ADDTOP Solar Charger (25000mAh) 4 Panels – much quicker some claim 4 hours in direct sunlight but the manufacturer says 25-50 hours

So what’s the point then?

You can see that it is slow to charge these banks in just the sun, around 50 hours! This compares to around 5 or 6 hours from mains electricity.

You may be asking now, what is the point in even trying to charge the power bank using the sun?

Most manufacturers therefore only really recommend charging from the sun to ‘top-up’ the battery or for use in emergencies.

This is how I use mine. I’ll charge it from the mains before I go on a trip and then I’ll leave it attached to the outside of my bag or on the ground when I’m camping to get some extra charge.

I still find this very useful, if you are out camping for a long time it can get you some vital battery which you might not have been able to get otherwise.

It’s a balance between practicality/ size and performance. With current solar technology, you would need several panels to provide the charge required to match that of your household plug socket. That wouldn’t exactly be the most practical solution for carrying around.

The nature of charging batteries too also means it will charge much more rapidly for the first 50% and then slow down thereafter. You may never use the sun to fully charge the power bank but might just use it to get a little extra ‘juice’ for those emergency situations when you are far away from the nearest power source.

Can you speed up the charging?

Add more panels

As you might have noticed with the examples. The ADDTOP which has 4 panels rather than the standard 1, charges much more rapidly.

panels give you more surface area for photons to strike and therefore electricity to be generated.

Taking this into account the best way to speed up solar charging is to add some more panels. This obviously requires you to have more space but there are some great options out there now.

The Nektek Solar Charger is a solar charger designed for the outdoors that has 3 decent size panels that fold up. There is no battery included in the unit but with USB outputs this will allow you to recharge your solar power bank more rapidly.

And because it has 2 USB charging points you can be recharging your device and recharging the power bank at the same time, making the best use of any available sunlight!

Using this you should be able to fully charge a large solar power bank in just one day.

Optimize conditions

This one is a bit more obvious, but make sure you optimize the chances of getting as much energy as possible to the panel. Keep it in direct sunlight and avoid shade.

If you have the option of staying still for a few hours then that will be better as you can move the panel and ensure it is always getting direct sunlight. If you are on the move and have it attached to a backpack for instance then a lot of the time you will be facing away from the sun or standing in the shade.

How many times will it charge my phone when fully charged?

This will again vary depending on the size of your power bank and the type of phone you are trying to charge. But from my experience with a 25,000mAh power bank, fully charged you can expect about 3-4 full charges of an iPhone.

As you now know it takes a long time to fully charge a solar power bank using just the sun’s energy. But I don’t think that really matters and it isn’t how these devices are designed to be used.

Charge them up fully before you go (of course make sure your home electricity is renewable too ) and then use the suns energy to ‘top-up’ the power bank to extend the use further than it would normally go. Think of the solar panel as more of a bonus feature.

If you are going ‘off grid’ for a while the reality is you will need to get yourself some more panels or you will be sat around for weeks! There are lots of great folding, portable solar panels sets out there now.

Rob is the head writer at Innovate Eco sharing knowledge and passion cultivated over 10 years working in the Environmental Sector. He is on a mission to build a community of people that are passionate about solving environmental problems.

Nekteck 20w solar charger. Goal Zero Nomad 14 Plus – (Discontinued)