From EarthTechling's Caleb Denison:
Solar chargers are a great way to power your mobile devices on the go and, because the devices are catching on, more and more varieties of them are coming available. We’ve covered and even reviewed a few of them in the recent past.
The trouble is, one of the common denominators of these devices is that they tend to be a bit pricey. For those with a little DIY electronics inclination and some free time on their hands, may we suggest taking a look at this slick little DIY solar charger with full assembly instructions available at Instructables?
We first came across this pocket sized solar charger in an Altoids tin via RedFerret and it appears just simple enough for anyone who knows which end is up on a soldering iron to pull off. The parts that are needed should be easy enough to find on EBay, at Radio Shack or through the inventor’s website at BrownDogGadgets.com. The tools needed include a soldering iron, solder, tin snips, a hot glue gun and some tape. Total estimated cost to assemble the DIY USB charger runs between $20-$30.
The device packs a small solar panel, some AA sized rechargeable batteries and a USB charging circuit (amongst other parts) into a small box like an Altoids tin. The instructions provided explain how to make simple, small modifications to enhance the device’s performance or scale down the size, if desired. The creator, Joshua Zimmerman, claims that the device is superior in several ways to many of the commercially available solar chargers out on the market, none of which seem to be able to stand up to the low cost of its construction.
If the project seems like a fun idea but perhaps a little outside of your DIY skills, the designer sells pre-made versions in a variety of different sizes and styles on his website.