Updated November 2017
As the competition for affordable and light weight models continues to grow, so has our review. We took a look at the current models on the market today, ensuring that our award winners remain. Anker once again dominates, and we've included a couple of new brands, like RavPower, Bernet, and iClever, as well as the new Goal Zero Nomad 7 Plus.
Best Overall Solar Charger
Anker PowerPort 21W
Great value for its size
Pocket too small to hold extra cords and accessories
Out of the twelve models, we have worked with out in the field, the Anker 21W
is the one that we always seemed to gravitate back to. This product was leagues above every other model in our performance comparisons and always seemed to charge our electronics quickly and efficiently off the grid. In previous years, we tested the Anker PowerPort 15W
and were thoroughly impressed. So, this year we checked out the more powerful 21W version, and we were sold. The Anker 21W
has all the same attributes we loved in the previous award winner, with 6W more power. For these reasons, the Anker 21W received our Editor's Choice Award winner. With PowerIQ technology and two USB ports, the Anker 21W sustained our gadgets with a steady, efficient stream of power derived from the sun. This contender was hard to beat regarding charging capabilities, weight, and price. For a less expensive, but equal in quality product, check out the Anker PowerPort Lite 15W
Read review: Anker PowerPort 21W
Best Bang for the Buck
Instapark Mercury 10W
Can charge two devices at once
The Instapark Mercury 10W
is a durable, reliable, and efficient workhorse of at a low cost. As a 10W, it's on the bottom end of the wattage spectrum in our fleet, but held its own charging phones and small devices. If you're looking for something durable and long-lasting for simple charging tasks at a reasonable price, then the Mercury 10W is for you. It provides a large, easy to access external pocket to store all your electronic accessories, which is crucial for protecting your gadgets when charging in the great outdoors. As an added plus, the Instapark Mercury 10W rings in under $50, which is a bargain for such high-performance model.
Read review: Instapark Mercury 10W
Top Pick for Lightweight
No protective cover
Single USB port
While most of the 12 models we tested came within ounces of each other on the scale, the Renogy 5W
blew the competition out of the water when it came to weight and portability. This sleek little puppy weighs only 5.6 oz, (whereas all the others fell between 12 and 16 ounces), and is about the size and thickness of a small clipboard. It is durable, easy to clean, and water resistant. Unlike the other models with a protective canvas outer covering, the Renogy has a barebones, simplified design that keeps it lightweight. It's a great alternative to the smaller, battery-included contenders we tested last year, combining lightweight design and portability with effective charging capabilities. For simple charging tasks, like keeping your phone battery full on a backpacking trip, the Renogy is a good option.
Read review: Renogy E.Flex5
Analysis and Test Results
Now more than ever, solar technology is growing in popularity, and we have many well-tested options when shopping for a portable model. Traveling around the southwest US during this testing period, we saw large solar arrays, of the grid homes with panels outside, to campers charging their smaller devices on the go. Not long ago, it was difficult to find a rigid, monocrystalline panel in a foldable, light design. Portable options were bulky, finicky, and didn't last long when exposed to the elements. Now, dozens of companies produce affordable, effective monocrystalline panels ranging from small 5W models to larger and more powerful 20W options for a faster charge. These monocrystalline models are much more effective and lightweight than their polycrystalline forefathers.
Here are the nine (of the 12) panels catching rays under the watchful eye of Castleton Tower in Southern Utah.
Last year's favorite, the Anker Powerport 15W
is constructed with industrial-strength PET polymer, making super-durable and able to charge devices quickly and efficiently. This upgrade sent the Anker 15W to the top of its class last year and remains a top contender this year as well. The PowerGreen 21W use the same PET Polymer facing,
making it an extremely durable option as well.
Folded up, the panels range in size from the large X-Dragon on the left, to the Goal Zero and the Renogy which have much smaller footprints.
We tested small wattage models that were portable, like the Renogy 5W
and the ever-popular Goal Zero Nomad 7
. We also added the Goal Zero Nomad 7 Plus
, which is much lighter weight than the original Goal Zero, but it costs more. Though they were two different models, both the Nomad 7's performed comparably in testing.
Then, we re-tested some of our favorites from last year, including the Instapark Mercury 10W
and the Anker PowerPort Lite 15W
. We also chose some with some extra wattage for faster charging; these models include the PowerGreen 21W
, the Anker 21W
, and the X-Dragon High-Efficiency 20W
. Solar technology is improving overall. Every one of these panels performed well, their metrics ratings ranging mostly due to their output capabilities (i.e., Wattage), rather than the design of the models themselves.
We recently updated our review to include two new models: both of which are made with a battery included. The iClever BoostCel 12W
looks like a traditional fold-out solar charger but has a very thin battery inside. This model performed quite well in comparison to our other mid-range models. The Bernet 24000mAh
battery/panel combo looks more like a giant battery with a small solar panel on it and performs in much the same way. It did not compare to the other 10W options in this review, such as the Instapark Mercury 10W
which vastly out-performed the Bernet
Charge Interruption Recovery
Is your panel going to quit on you just because one tiny cloud passes overhead as you left it out on what appeared to be a cloudless afternoon? Or is the solar model strapped to your backpack causing your phone to constantly vibrate as the connection goes in and out from the USB port? These are the questions we addressed in our charge interruption recovery metric. To test these models, we measured the amount each one charged within a half hour span first in full sun, and then again in intermittent sun and shade. We also measured the output power before and after the charge interruption to see if the model could get back on track after being shaded.
The highest performing models in this category were the ones with more massive wattage, especially the Anker Powerport 21, our pick for Editors' Choice
. The Renogy 5W
scored low in this category because it has a small wattage. This makes it more difficult for the Renogy
to return to full output after an interruption. Those with a larger surface area also tended to do better in this metric, because there are more cells exposed to the sun at one time. This is a benefit of the Instapark Mercury 10W, which unlike the other two medium watt panels
, has three panels of cells, rather than two.
The Instapark Mercury 10W working to charge a battery in prime conditions and sun orientation.
The included battery pack of the iClever BoostCel 12W
and the Bernet 24000mAh
also help in this metric, as the panels can fall back on the battery to continue a charge, even when the cells become shaded. That said, the iClever 12W
worked much better to recover from an interruption since it has more surface area overall and a stronger output capacity.
Here the iClever works to charge our external battery as we test its ability to recover a charge after an interruption. The panel works well because it can rely on its internal battery when the cells are blocked.
has such a small surface area with cells on it that it runs more of a risk of being shaded as the sun's orientation changes. It also just isn't able to gain as much power from the sun as a more substantial model can.
These are the types of conditions we wish for when charging electronics using solar power.
The majority of the time, these solar panels are being used to charge cell phones when electricity is not available. Because this is typically the case, our highest rating metric in testing was Phone Charging Speed. We wanted to know long it took each model to charge an iPhone 6 (the main phone used for testing) as well as our small external battery packs. We set each one out in the direct sun for 30 minutes and measured how much the phone charged.
This way, we could get a good read on how efficiently the individual models worked for longer periods of time. We also timed how long it took for each one to charge our 6,000 mAh portable battery packs, so we had that data to compare as well. In general, these batteries can charge an iPhone from 0 to 100% about two times.
The X-Dragon 20W panel has multiple loops to hang it up oriented toward the sun. However, we found that it worked well propped up on the ground instead, especially since it is such a sturdy panel and can hold itself up easily. This model also had the fastest charging speed out of any in our fleet.
We found a broad range in the panel's ability to charge these batteries, from the X-Dragon
, which charged to full in 3 hours 30 minutes, to the Renogy
, which took 4 hours to charge the same battery only 9%. The Bernet
model also scored a relatively high score that was on par with award winners.
In direct sun, the Bernet panel will charge a small device fairly efficiently, especially when the battery pack itself is charged.
This considerable variability is due to the extensive range in output power of the contenders we tested. 21W is four times as powerful as a 5W device, so it makes sense that panels like the X-Dragon 20 earned a 9 out of 10, the highest in our testing
, alongside the Anker 21W
- both are much faster. In this test, the X-Dragon 20W
outperformed even our Editors' Choice winner, the Anker 21W
, by charging our external battery pack the fastest. The Anker 21W
was a close second, though, with the Instapark Mercury 10W
, holding its own among the 15W and the 20W models.
Using this USB multimeter, we found that the measured output was often times less that the panels claimed.
For its size, the Renogy E.Flex5
held its own in both phone and battery charging efficiency. The Nekteck 14W
and the RAVPower 16W
were our two slowest performers and neither was able to fully charge our battery pack within a four hour period, unlike the other 14W and above models in this review. We found that it is overall a better idea to invest in a contender with a higher wattage since a fast charge is typically what we look for in a solar charger first and foremost. For a speedy and efficient charge, a more significant watt option is more efficient. That is unless you're trying to save weight or money, then a less powerful model might be a good compromise.
Multiple Device Charging Speed
As you might guess, when tasked with the challenge of charging multiple devices at once, the more powerful models performed better than the less powerful ones. Six out of the twelve chargers in this year's testing had numerous USB ports- the 5W and 7W models don't have the power to sustain two gadgets at once. That's why on the metrics chart, the three low watt models get a 2 out of 10, compared to the models that can charge two devices.
For the Anker 21W
, charging two devices was a walk in the park. This model delivered a consistent charge to both devices, unlike its competitors.
In prime conditions, the Anker 21W charges two devices simultaneously. With less direct sun, even this powerful panel will take substantially longer to charge using both USB ports.
lapsed in and out of charging on both devices and the Powergreen 20W
appeared to be charging each device, but we never saw an increase in percentage. With the Anker 21
being the only contender to score a 9 out of 10 for this metric, the PowerGreen 20
was the next highest scorer, earning a 6 out of 10. The PowerGreen was followed by the Nekteck 14
, Instapark Mercury 10
, and Anker Powerport Lite
, earning 5 out of 10s.
The PowerGreen is the largest, and heaviest of the panels we tested. But, it was one of the top scorers that could charge multiple devices.
Since their job is to lie out exposed to the elements, we had high hopes for these models regarding their ability to hang tough as we took them through deserts, mountains, sun, wind, and rain. Through months of testing, nearly all the contenders stood up to the challenge. The canvas protective fabric is like an exoskeleton-guarding the important insides of the panels. Solar technology seems to be advancing too, with companies working to make cells more durable and resistant to sun and water damage.
When scanning through customer reviews online, we saw some complaints about various models withering and warping in the sun. Because of this, we were extra vigilant, even when we set them out in the blazing southern Utah desert sun. Thankfully, in our testing period, none of the chargers endured much damage at all. These are hardy machines, with technology advancing every year, solar panel companies have come leaps and bounds in the construction of portable options.
There is a fine line between exposure and turning your panel into a frying pan. Be aware that some panels will warp if left out in very hot conditions.
Models with external storage pockets like the Anker 15W
, the Powergreen 20W
and the Instapark Mercury 10
won us over because their pocket not only protects extra gadgets but also keeps the USB port dry and covered when charging. Some of the models, like the Goal Zero Nomad 7
, have a mesh pocket, which is nice to see what is inside, but also tends to wear out faster than the more burly canvas construction. Others, like the Renogy 5W
and the Bernet 24000mAh
lack pockets, which makes them more streamlined but also harder to keep track of. The Renogy 5W
s USB port is well protected on the back of the panel, but the ports on the Bernet are exposed to the elements and often got dirt in them when we propped it up on its side to charge.
Sometimes a landscape orientation works better for the charging location. The versatility and durability of the Renogy are of its best features.
Weight and Portability
Since the primary function of all these portable models is to be, well mobile, this is an important category. A model that is too heavy or bulky will be left behind to collect dust in the closet when you set out on your next adventure. The models range from a mere 5.6oz, the Renogy 5W
, the only model to earn a 10 out of 10, to the PowerGreen 20W
, which weighs in at 16.8oz. For the most part, smaller options will be less powerful, but some of the low wattage panels, like the Goal Zero Nomad 7
and the Outad 7W
, weigh almost as much as the 20W powerhouse panels.
Compared to the Anker 21W, the Renogy is pocket sized. Its charging capabilities are much less than the Anker 21W, however.
Some come with lots of accessories and extra features, which make them easier to use and exciting, but also make them bulky and unappealing to carry on long trips. There is a happy medium, we found, between overkill and overly simple.
Here's the tiny Renogy panel in comparison to a standard Climbing magazine. They are about the same thickness, but the Renogy has a much smaller footprint.
This year we mostly avoided testing any models with battery packs included, though many of the companies in this review provide these products. To make the review more standardized across the board and to simplify the testing, we used a standard battery pack and USB for all the panels. We used the 1byone 6,000 mAh Portable Charger, as it was an inexpensive external battery with good reviews, used mainly for charging phones and small gadgets.
Accessories can quickly add up to create a heavy, cumbersome set up. These small external batteries work great to keep your electronics charged without creating a junkshow on the panel.
Many people choose to combine a solar charger that doesn't have an internal battery with an external battery. This allows the panel to charge the battery during the day while the device is being used. Then the device can be charged at night from the external battery. External batteries are an essential addition, too, because as our tablets and smartphones demand higher power (like 2A charging ports), this becomes harder to produce from the sun (which is variable at best), and requires higher wattages, and thus more panels, meaning more weight and bulk. The best option, in our opinion, is to have a less strong (and lighter weight!) solar charger that charges a high-quality external battery, which can, in turn, produce the necessary 2A of current for our devices.
Home Solar Models
The world headquarters of our sister site, SuperTopo.com, is now solar powered. Check out this detailed guide on how to choose home solar panels
. The article contains photos, video, and many external links to help you evaluate if going solar is right for you.
Deciding on the right solar panel can be an overwhelming task. To make it easier to wrap your head around, figure out what you will be using it for, and go from there. Are you running a mobile office and need to keep multiple, energy-hungry devices happy? Or are you just concerned with having a fully charged phone on a weekend excursion? The smaller watt options are going to be less expensive, and thus less powerful. As you increase the wattage, the panels will just become more and more efficient. The sky is the limit, it just depends on how much money you are willing to spend. We put all 12 of these competitors to the test and found that there are some that perform better than others, and a higher price tag doesn't necessarily mean a better product. We hope that our thorough tests and reviews of these products will be useful to you as you shop around for your new solar charger. If you need further assistance in finding the model that best suits your needs, check out our Buying Advice