GadgeTell Review: Etón BoostSolar Backup Battery

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With the green energy movement well under way, more and new energy products are available for consumer use. The most popular type today is the solar panel. As gadgets have trended toward wireless function and portable form, solar panels have evolved in order to complement and accessorize with emerging tech.

Eton Etón BoostSolar Galaxy S2

Size compared to a Galaxy S2

Many solar panels currently available for purchase are both affordable and compact. Easily able to fit in our bags or backpacks, some are as small as a basic smartphone while others can reach the size of a large D-ring binder.

Etón Corp. is a developer of solar-powered and emergency-preparedness gear. They make battery backups, portable weather alert systems, and solar panel-equipped gadgets. I managed to get my hands on the [easyazon-link asin=”B00BGLIXWO” locale=”us”]Eton BoostSolar[/easyazon-link] to see how well this compact, solar-rechargeable battery performs.


The Etón BoostSolar features a solar panel with a detachable 5000mAh battery. What’s great about this design is that the panel and battery both have Micro USB ports for charging in/out. You can charge from the sun or outlet, and the battery can be removed and act as a standalone external battery. The drawback, of course, is that once the battery dies (eventually), the solar panel is no longer useful until you purchase a replacement from Etón.

Eton Etón BoostSolar rear

Battery clicks right out

The BoostSolar panel is reasonably thin, making it an ideal item to slide into bags, backpacks, or even purses. The weight is evenly distributed across the unit, so you can quickly and easily prop it up from any side.

While the device feels of quality, sturdy construction, I wouldn’t necessarily call it “rugged.” It has survived some drops, splashes of water, and dirt, but it’s neither waterproof nor meant to endure harsh activity.

It doesn’t really look like a solar panel from a distance. I’ve had people mistake it (or question me about it) for some smartphone- or tablet-related device, likely since it easily blends in with other gear that I have. You can carry it around with you and not feel like people would identify you as “that person who is carrying a solar panel.” If you care about that.

The operation is simple. There is one button to push to check the LED lights for the battery level. Those LED lights blink while charging from the sun or outlet. Charging a device happens as soon as you plug it in.

Solar Charging

Through many solar-charging tests, the Etón BoostSolar was able to consistently deliver at least 1600mAh worth of battery energy from 7.5 hours (approximately) of full, continuous sun. There are some spots in my backyard that get zero shade all day as the sun passes over, which is where I placed the panel to charge. I made sure the panel had an good angle of inclination (ideal for best performance), and I also turned it every 2 hours to full-face the sun (also critical).

Eton Etón BoostSolar battery ports

Standalone 5000mAh input/output USB ports

For reference, 1600mAh is good for a full iPhone 5 charge (and then some), roughly 2/3 of a full charge to a Samsung Galaxy S4, and only a half charge to my Samsung Galaxy Note 2.

The weakness with this solar panel is how shade and indirect sunlight affects the charging ability. Of course, shade and indirect sunlight affects all solar panels, though there are certain characteristics that allow some panels to be more efficient than the standard.

The BoostSolar doesn’t happen to be one of those. Don’t expect it to charge through clouds, even if they are the spotty dirty-white or blue-gray ones. If you can stare at the sun through clouds without shading your eyes or squinting all the way, the BoostSolar will (most likely) not pick up a charge. You can tell by checking to see if the LED light is blinking or not.

Eton Etón BoostSolar sunlight

Charges through sparse clouds (left) but not light clouds (right)

If you’re planning to hang the BoostSolar off your backpack while hiking (or throwing it on your dashboard while driving), you’re going to be out of luck.

It’s not necessarily the fault of any solar panel – they just aren’t that efficient when not constantly facing the sun at a decent angle of inclination.

Some people might claim a specific brand or model of solar panel works great like that (I hesitate to believe it), but I can verify that the Etón BoostSolar is not one of those.

I took it with me on a walk at the park, setting it flat on top of the sun visor of my daughter’s stroller. I kept track of the time that the panel spent in the shade versus sun. After a one hour walk, the Etón BoostSolar spent a total of 41 minutes in the sun. However, the trail alternated between full shade and full sun in a variety of bursts. The end result? I got less than a 1% drop of energy into a smartphone before it was completely out.

The battery does not pass energy through, meaning you can’t charge the battery and power a device at the same time. You can do one or the other, but not both.

Charging out

You don’t need the sun to power up the Etón BoostSolar! It can plug in via USB to charge, like any non-solar external battery pack. Once it’s full, the charging lights turn themselves off.

Your standard external battery pack has a 70% efficiency rating. This means that 30% of the battery’s total capacity is used up in order to deliver the other 70%. So a 1000mAh-listed battery would have only 700mAh of useable energy. The Etón BoostSolar, with its 5000mAh battery, should have an expected 3500mAh of usable power. That in itself is sufficient to give my Samsung Galaxy Note 2 one full charge with almost an extra 10%.

But that’s not exactly how it’s been happening.

Eton Etón BoostSolar Gorillapod

Perfectly-sized to work with a Gorillapod and clamp

After weeks of charging the panel (mostly by outlet, since it’s faster, but also sun) and using it to power smartphone batteries (Galaxy S2 and Galaxy Note 2 batteries tested), I found two inconsistencies, or quirks.

The Etón BoostSolar was able to deliver efficiencies greater than 70%, but also with a wildly-fluctuating rate of charge.

The 5000mAh battery output has ranged from 71% to 85% efficiency, with the average being 78%. The total time it took to empty out the BoostSolar has ranged from as little as 4 hours (ridiculously fast) to as long as 17 hours (ridiculously slow), with the average being 11 hours.

The efficiency of outputs didn’t seem to matter, as similar efficiencies still presented different times for complete disbursement. All of the charging tests happened in the same indoor location, free of sun and heat exposure. The smartphones were restarted prior to each charging session as well.


When it comes to solar charging, I consider the Etón BoostSolar as more of a casual, backup, or emergency type of device. It will power the gadgets you have; it simply might require a bit of patience and vigilance. However, if you take the compact size and the standalone ability of the battery into consideration, this solar panel makes a great addition to anyone’s gadget or gear bag.

Eton Etón BoostSolar Maxpedition Sitka

It won’t charge much, but it looks cool with Maxpedition gear

In terms of getting the most use out of the Etón BoostSolar panel, camping or beach trips have been ideal. Leaving the panel in the sun all day lets me recharge my smartphone partway in the evening.

I do have to supplement with some other power source, depending on how much I’ve drained my smartphone.

Smaller, less power-hungry devices would likely fare better to charge than smartphones or tablets. Lights, wireless headphones, and portable speakers come to mind first.

I’d say this solar panel is sufficient to keep the music going all day and night. If you’re expecting the BoostSolar to charge your gadgets while hiking (or have complained about it not doing so), I recommend brushing up on the science behind solar energy. It’ll temper your expectations and help you get the most out of any solar panel you use.

As long as you understand how to maximize use with the Etón Boost Solar, you will find it affordable and priced fairly, given its power and versatility. As for the quirks – the higher battery efficiencies are a boon, though you’ll infrequently have to accept charging at a snail’s pace.

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