We recently headed out to Palo Duro canyon for a few days of tent camping in the cold, coyote-infested wilderness. I thought perhaps it might be a little hard to get our phone batteries to last the duration of the trip. Luckily, I had some random leftover parts laying around from various dumpster dives and such, and ended up having everything I needed to build the circuit! The whole thing required pretty minimal soldering, which would be nice if I wasn’t itching to use the Weller (!) I got as a Christmas gift.

The whole circuit goes from solar panel to a USB/DC/Lipo solar charger board. The Lipo load is connected to one 2200Mah Lipo battery, but those things are typically at 3.7V- 4.50V, and I wanted it to be useable to either charge a phone directly or another, larger battery in tandem. I used the Adafruit Powerboost to kick the voltage up enough to adequately charge the phone.

Now a big battery lives in my backpack and is charged as the days go on by sunlight. Since I usually only use the big battery less than once a week, this a pretty nice setup, almost guaranteeing I’lll have charge when I need it!

Yes duct tape was used liberally in the creation of this project.