Looking for a portable and efficient solar panel to keep your electronics charged on your next backcountry venture? We sifted through hundreds of models, narrowing it down to the top 18, which we then purchased and put through a series of in-depth tests. Options abound, we opted for a fleet that are designed for various purposes. While some are small and portable, others are designed to charge large electronics, such as laptops. We put each model to the test while car camping and living on the road, and also brought each one into the backcountry, where an effective panel is especially important. We've weeded out the imposters from the legitimate, efficient panels, with our side-by-side tests revealing which of these panels truly perform and are the cream of the crop, and which ones fall short. Read on to learn more about the right panel for you.
The Best Portable Solar Panels and Chargers of 2018
A number of products have seen updates or been discontinued altogether; for this reason, we've updated our review for 2018, adding in five new contenders. We've awarded a new Editors' Choice this year, with the BigBlue 28 taking home the top prize. The Instapark Mercury 10W remains our Best Buy, while the Renogy E.Flex5 is our Top Pick for Lightweight. Though not all newly added panels won awards, you can read more about the Yolk Solar Paper, Suntactics S-Charger 14, Goal Zero Nomad 7, and RAVPower 24W.
Best Overall Solar Charger
If your main goal is efficient charging, the BigBlue 28W is tough to beat. With a whopping 28 watts of power, and no additional weight or size, the BigBlue will keep your gadgets charged. The panel has a built-in auto restart function, which comes in handy in cloudy conditions, as well as an ammeter, so you can track the panel's output as you charge. The final cherry on the top is that this panel costs only $60, which makes it a contender for our Best Buy Award on top of taking the cake as our Editors' Choice winner.
The downside is that this panel weighs in at 23.5 ounces. For backcountry use or any other trip where weight is a concern, this panel may not be the best choice. For us, the effectiveness of this panel "outweighed" its bulky size.
Read review: BigBlue 28W
Best Bang for the Buck
Instapark Mercury 10W
The Instapark Mercury 10W is a solid work-horse of a panel. It won't break the bank, it charges efficiently and is designed to last. In comparison to panels of a similar capacity, the Mercury had some of the best scores in charge interruption recovery and charging speed. It also has a large storage pocket and is overall one of the more durable panels we reviewed.
One of the downsides to the Mercury is its failure to charge multiple devices at once. Like many of the panels with dual USB ports, this panel struggled to charge multiple devices effectively. It's only a 10W setup, which means each USB port only gets about 5W, or less, in full sun. The panel is also a bit heavy and bulky, especially for its relatively small output capacity. That said, the Mercury 10W was one of the highest-ranking panels in terms of durability. Overall, this panel is excellent, as it offers an inexpensive price point and is effective.
Read review: Instapark Mercury 10W
Top Pick for Lightweight
Since our other two award winners focus more on performance rather than weight and size, we wanted to include an option with weight as its strong suit. Behold the Renogy E.Flex5! This panel is sleek and durable, which as it turns out, is a difficult combination of features to nail down. Though the Yolk Solar Paper weighs less (a mere 5.1 ounces as compared to the Renogys 6.1 ounces), it lacks the durability of the heavier model. Similarly, the Suntactics S-Charger 14W is slim and sleek, but weighs more and costs much, much more than the Renogy. The bare-bones design, light feel, and relatively low price tag make the Renogy a no-brainer as our Top Pick for Lightweight panels. This panel makes for a good alternative to the small battery pack/panels we have tested in the past.
The panel performed relatively well regarding charging speed for its size but could not handle interruptions very well. Its small size also means that it charges slowly. For phones and other small devices, the Renogy performs adequately, but we should note that it took four hours to charge our battery to only 9%. This may seem shocking, but it is just the way it is with small capacity panels. If minor charging is all you need, the Renogy will do the job!
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, from 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.
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 costs more. Though they are two different models, both the Nomad 7s performed comparably in testing. Additionally, we added in the new Yolk Solar Paper, which is the lightest, smallest panel we have ever reviewed. It did not stand up to the Renogy, which is still our Top Pick for Lightweight. Yet another addition to the non-traditional panels is the Suntactics S-Charger 14. This panel was one of our new favorites, though it comes with a hefty price tag. This panel is thin and durable, like the Renogy panels we tested in past years but is much more efficient.
We also re-tested some of our favorites from last year, including the Instapark Mercury 10W. We also chose some with some extra wattage for faster charging, like the PowerGreen 21W and Voltaic Systems Arc 20W. Solar technology is improving as a whole; while each panel performed well, their metric ratings range in scores, mostly due to their output capabilities (i.e., wattage), rather than the design of the models themselves.
Our 2017 update included two new models, both of which include a battery. 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 size of the solar cells is similar to those of the Instapark Mercury 10W and the Suntactics 14W, which meant that the iClever stood up to these panels when it came to efficiency.
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. More often than not, these small battery pack panels do not charge very quickly because the solar cells are not big enough to work efficiently. Other panels, like the Instapark Mercury, are triple the size of the Bernet, and thus charge more quickly.
This year we have also included two solar setups that are designed to charge laptop computers: the Voltaic Arc 20 and the X-Dragon 40W are the two models we tested. Both had their hold-ups, and our overall take away was that there is room for improvement in this technology. The panels had a difficult time charging the large batteries, and the batteries themselves struggled to charge our MacBook computer. Additional cords are needed as well, and a lot of power is lost via all of the connection points.
Unlike some other products we test here at OutdoorGearLab (we've tested bikes that cost more than our cars!) portable solar chargers all tend to be on the affordable end of the spectrum, ranging in price from $30 to $280. However, even with such a reasonable price point, some models had much better value than others. For example, our Best Buy winner, the Instapark Mercury 10W ($63 list price, often less online) had the same overall score as products that cost twice as much. If you want to have the best, it will only take another $10 to get you there - our new Editors' Choice Award winner, the BigBlue 28W is not only an efficient panel but also comes at an affordable price, which really won us over.
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 of 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. The Renogy 5W scored low in this category because it has a small wattage, which 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 options, has three panels of cells, rather than two.
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 stronger output capacity.
The Bernet 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.
Some panels, like the BigBlue 28W and the Suntactics S-Charger 14, now come with a built-in auto-restart function. This allows the panel to automatically reconnect to your device after being shaded. Though the panel will still charge slower in cloudy conditions, this feature helps at least continue the flow of power in less-than-ideal charging conditions.
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 obtain a good read on how efficiently the individual models worked over extended 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, this size battery can charge an iPhone from 0 to 100% about two times.
We found a broad range in ability to charge batteries, from the X-Dragon, which charged to full in 3 hours 30 minutes, to the Renogy, which took 4 hours to get the same battery only 9%. The Bernet model also scored a relatively high and was on par with the award winners.
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 BigBlue earned a 9 out of 10, the highest in our testing. In this test, the BigBlue outperformed all by charging our external battery pack the fastest. The Instapark Mercury 10W held its own among the 15W and the 20W models.
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. Overall, it's 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 panel first and foremost. For speed and efficiency, a more significant watt option is more efficient. That is unless you're trying to save weight or money, in which case 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. Twelve out of the twenty chargers in this year's testing had multiple USB ports. The 5W and 7W models simply don't have the power to sustain two gadgets at once, which might not be what you're looking for anyway. 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.
The X-Dragon lapsed in and out of charging and the Powergreen 20W appeared to be working, but we never saw an increase in percentage. The PowerGreen 20 was the highest scorer, earning a 6 out of 10. Next was the Nekteck 14, and the Instapark Mercury 10. Some panels, like the Wildtek Source 21W now have three USB ports, but we found this panel to have the same issues as many of the 2-port versions out there. It appears that panels with a higher wattage are more effective at charging multiple devices at once. With this in mind, check out the BigBlue 28W or the X-Dragon 40W if this is a feature you find important.
Since their job is to lie out exposed to the elements, we had high hopes for these models when it came to 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 noticed 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, and with technology advancing every year, solar panel companies have come leaps and bounds in the construction of portable options.
Models with external storage pockets, like 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 helpful for seeing what is inside, but also tends to wear out faster than a 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 your cables. 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.
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 5.6 ounces, like the Renogy 5W, the only model to earn a 10 out of 10 for portability, to the iClever BoostCel 12W, which weighs in at 21.5 oz. For the most part, smaller options will be less powerful, but some of the low wattage panels, like the Goal Zero Nomad 7 weigh almost as much as the 20W powerhouse panels.
Some come with lots of accessories and extra features, which make them easier to use and more exciting, but also make them bulky and unappealing to carry on long trips. There is a happy medium between overkill and overly simple. Though portability is key, we found that we focused more on performance in our testing, since the panel is just dead weight if it doesn't work at all. That was our reasoning behind handing out awards to heavier panels like the BigBlue 28W and the Mercury 10W.
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.
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 you're using your devices (phone, GPS unit, and the like) and you can charge your device at night via 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 charger 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 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 become more and more efficient. The sky is the limit, but it depends on how much money you are willing to spend. We put all 18 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 article.
— Jane Jackson