Introduction: Solar USB Charger for Smartphones (including an IPhone)

About: Builder, Baker, Athlete Maker. Enthusiast of things.

We are in constant need for power these days... why not harness the sun! I've seen a few of these on here, so my take is to offer some clear wiring if you want to give it a go... and some drawings for your own box if you have access to a laser cutter. I also give you an alternative to ditch the solar panels if you just want to straight up wall charger your thing.

Step 1: Parts

Things you'll need:

  • A container or in this case a laser cut (birch plywood 3mm) finger joint box.
  • micro USB charging module - like this
  • Standard USB size battery converter step up module --- this is key as these can varyin their output! you need one that will output enough watts for the fancy smartphones - like this
  • Battery - you need enough juice to boost the USB - I have here a rechargeable LiPo 3.7V 2000mah, it gets it done. buy here
  • 2 pin Rocker switch - this
  • Solar Panel... you could put small ones together or have 1 large one - like this
  • rectifying diode, this allows your electrons to flow into your battery but they can't glow back out
  • wires to connect your parts
  • hot glue to insulate wiring and hold box together

Here are my box files, I loaded svg and plt files since the plt works well on our local laser cutter.

(If you want to get all your parts from one source (and pay less), you can check out Kitables, they sell 2 versions of this kit.

Step 2: Wiring Diagram

Here's how I wired my charger with these components

Step 3: Glue Your Box, Mostly

Glue up 5 of your 6 sides to work with...

Step 4: Insert Switch

Put the switch in before wiring.

Step 5: Solder Solar Panel

Start by soldering wires to the positive and negative terminals of your panel. Then slip the wires through the small holes on the unglued part of the box.

Step 6: Diode

Solder rectifying diode to the red panel wire (+) with the black line furthest away from panel.

Step 7: Solder Panel Wires

  • Solder the diode (from the solar panel/red wire) to the IN+ hole on the charger module.
  • Solder the black panel wire to the IN- on the charger module.

Step 8: Solder Some Wires

  • Solder a couple of black wires together and a couple of red wires (color doesn't matter, I just like to use the same ones to keep things clear).
  • Solder black wire set to the BAT- terminal on the charging module and the red wire set to the BAT+ terminal
  • Solder one of the black wires (from the set on the BAT-) to the black wire (negative) on your LiPo battery.
  • Solder one of the red wires (from the set on the BAT+) to the red wire (positive) on your LiPo battery

Step 9: Solder to USB Booster

  • Solder one wire from the switch to the USB Booster (IN-)
  • Solder a red wire from the charging module to the USB Booster (IN+)
  • Solder remaining black wire form charging module (BAT-) to the other switch pin.

Step 10: Charging

  • Plug a mini USB cable into the charging module port (the small one).
  • Takes ~2hours to fully charge Lipo from empty. Or set panel in sunlight, takes ~ 14hours to fully charge.
  • To charge your device, plug your charging into the standard USB port, turn on switch to direct charge from battery to device.

Step 11: No Solar? No Problem.

If you want to ditch the solar panel here's the new wiring diagram.

And here are the new box files, the size is notably smaller because you're no longer trying to fit a panel.

Solar Contest 2016

Participated in the
Solar Contest 2016