The Nekteck 21watt Solar Panel can charge nearly any USB device with the sun. We have used the Nekteck to power the XTAR VC4 Battery Charger. Although we don't use it all the time, we have successfully recharged AA, AAA and 18650 batteries with the sun. I like this 18 ounce solar panel. It is good for outdoor activities, camping, and trips and it doubles as an emergency device. If the power is out and you have sun you can power two 2amp USB devices. Note the newer iPhone and Samsung prefer 5amp USB, so this 2amp unit takes a while to charge them. It can be slipped in a backpack 6.3x 11.1x 1.06in folded or 26.3x 11.1in spread out.
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