We took a look at the huge variety of solar chargers available on the market today. While Anker continues to win our Editors' Choice, year after year, we've tested a new product from Renogy, which is not only lightweight but inexpensive. Anker and Instapark remain in the lineup, with fresh competitors from Renogy, X-Dragon, and Powergreen being introduced - and scoring towards the top of our fleet. The competition for light weight and affordable contenders continues to expand.
Best Overall Solar Charger
Anker PowerPort 21W
Great value for its size
Pocket too small to hold extra cords and accessories
Time and time again, the Anker 21W
panel was the panel we reached for to quickly charge any device in the field. It outperformed every other contender in most categories and charged our gadgets reliably when we were far from a power source. Anker has been creating durable, easy to use panels for years, and this year the 21W took the cake for our Editor's Choice since it had all the same qualities as last year's winner, the Anker Powerport 15W
, with even more power! The Anker 21W has PowerIQ technology, which delivers a smooth, steady charge to devices through its two, high amperage USB ports. Anker continues to be a leader in solar panel technology with this trusty and intuitive panel. Are you are interested in the Anker 21W, but aren't sure about throwing down for such a large solar charger? Look no further than the Anker 15W
, which is an efficient, lighter-weight version of this award-winning panel.
Read full 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 panel, it's on the bottom end of the wattage spectrum in our fleet of panels, but held its own charging phones and small devices. If you're looking for a durable, long-lasting panel for simple charging tasks at a reasonable price, then the Mercury 10W is for you. This panel has 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 panel.
Read full review: Instapark Mercury 10W
Top Pick for Lightweight
No protective cover for panels
Single USB port
While most of the nine panels 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 panel weighs only 5.6 oz, whereas all the other panels fell between 12 and 16 ounces, and is about the size and thickness of a small clipboard. It is durable and easy to clean, as well as being water resistant. Unlike the other panels 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 panels 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 full 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 panel. 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 panels 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 panels to larger and more powerful 20W panels for a faster charge. These monocrystalline panels are much more effective and lightweight than their polycrystalline forefathers.
Here are the nine 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 panels, 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 panels that were portable, like the Renogy 5W
and the ever-popular Goal Zero Nomad 7
. Then, we re-tested some of our favorites from last year, including the Instapark Mercury 10W
panel and the Anker PowerPort Lite 15W
. We also chose some panels with some extra wattage for faster charging, these panels include the PowerGreen 21W
, the Anker 21W
, and the X-Dragon High-Efficiency 20W
panel. Solar panel 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 panels themselves.
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 panel strapped to your backpack causing your phone to constantly vibrate as the connection goes in and out from the panel's USB port? These are the questions we addressed in our charge interruption recovery metric. To test these panels, we measured amount each panel charged within a half hour span first in full sun, and then again in intermittent sun and shade. We also measured the output power of each panel before and after the charge interruption to see if the panel could get back on track after being shaded.
The highest performing panels in this category were the panels with larger wattage, especially the Anker Powerport 21, our pick for Editors' Choice
. The Renogy 5W
scored low in this category because it has a low wattage. This makes it more difficult for the Renogy
to return to full output after an interruption. Panels with larger surface area also tended to do better in this metric, because there is 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.
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 panel to charge an iPhone 6 (the main phone used for testing) as well as our small external battery packs. We set the panels 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 panels worked for longer periods of time. We also timed how long it took for each panel to charge our 6,000 mAh portable battery packs so we had that data to compare as well. In general, these batteries have the capacity to charge an iPhone from 0 to 100% about two times. We found a large range in the panels' 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%. This large variability is due to the large range in output power of the panels we tested. 21W is four times as powerful a panel than 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
panel 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 panels and the 20W panels.
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
was our slowest performer and was unable to fully charge our battery pack within a 4-hour span, unlike all the other 14W and above panels. For a speedy and efficient charge, a larger watt panel is more effective. That is unless you're trying to save weight or money, then a less powerful option might be a good compromise.
Phone Battery Saving Tips
The fastest charge is the one you never have to do. Here are some iPhone Battery Saving Tips for Backpacking.
Multiple Device Charging Speed
As you might guess, when tasked with the challenge of charging multiple devices at once, the more powerful panels performed better than the less powerful ones. Six out of the nine chargers in this year's testing had multiple USB ports- the 5W and 7W panels don't have the power to sustain two gadgets at once. That's why on the metrics chart, the three low watt panels get a 2 out of 10, about the panels that can charge two devices.
For the Anker 21W
, charging two devices was a walk in the park. The panel delivered a consistent charge to both devices, unlike its competitors. The X-Dragon
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, followed by the Nekteck 14
, Instapark Mercury 10
, and Anker Powerport Lite
, earning 5 out of 10s.
Since their job is to lie out exposed to the elements, we had high hopes for these panels regarding their ability to hang tough as we took them through deserts, mountains, sun, wind, and rain. Through months of testing, nearly all the panels 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 panels withering and warping in the sun. Because of this, we were extra vigilant, even when we set the panels 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 panels.
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.
Panels with external storage pockets, like the Renogy E.Flex5
, 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 panels, 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.
Weight and Portability
Since the primary function of all these portable solar panels is to be, well portable, this is an important category. A panel 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 panels 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.
Some panels 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.
This year we avoided testing any panels 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 important 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 potent (and lighter weight!) solar panel that charges a high-quality external battery, which can, in turn, produce the necessary 2A of current for our devices.
Home Solar Panels
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 panels 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 nine of these panels 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