Recharge it with Goal Zero’s Guide 10 Plus Battery Pack that’s been soaking up the sun’s energy all day, thanks to the twin solar panels of Goal Zero’s Nomad 3.5 you’ve had hanging off your pack as you’ve hiked.
The Guide 10 and the Nomad 3.5 are sold together, along with four AA batteries and some connection cables, as the Guide 10 Plus Mobile Kit, a mighty solar power providing package.
The Guide 10 is essentially a battery charger that holds four AA (or AAA, with an adapter) NiMH rechargeable batteries that is charged by the Nomad 3.5 via a special “Ultra Charge Solar Cord” (whatever that means). It’s also a small, rather powerful flashlight.
I’ve used other portable solar panels in the past with varied results (and by varied I mean from “fair” to “poor” to “crappy”), but so far this little number delivers power where it counts. On some routine field testing, the Guide 10 loaded up with 4 AA batteries charged in about 6 hours, as advertised. It even charges in less than direct sunlight (which has always been a frustrating flaw in portable solar panels), although a little more slowly.
The only downside I’ve discovered so far is that it isn’t designed to charge smartphones directly — though there’s some confusion on this point (sadly, reviews and FAQ on this page are not linkable, but the info can be found by searching for “smartphone”), but the phone charges just fine via USB from the Guide 10.
All that, and the whole thing weighs in at just under a pound. And I’ll be able to save a little more weight by carrying fewer batteries, so it’s a win all around.