Welcome to the summer of solar! Why not soak up some free power from the sun? Charge your gadgets on the go by making your own solar battery charger, then affix it to your favorite handbag or backpack. This is a fun soldering project you can build in an afternoon!
When you’re out in the sun (or as long as your bag is), the battery charges up. You can simultaneously charge your phone when the sun is bright, and the battery will keep supplying juice long after the sun goes down.
We've upgraded this project to use the newer PowerBoost 500 Basic and a 3D printed enclosure, check it out!
Before you begin, read through the following guides:
Follow the instructions in the Solar LiPoly Charger Guide
, but when it comes time to solder in the capacitor, bend it over so it lays down on the board first. This will help it fit better with everything else inside the enclosure.
Assemble the MintyBoost as instructed
, but lay down the tall capacitors and boost converter before soldering.
Instead of soldering on the MintyBoost's battery holder, solder on the JST cable that comes with the solar lipoly charger kit (red to + and black to -).
Plug the MintyBoost into the LOAD port on the solar charger, and plug a lithium polymer battery into the BATT port. Test that your MintyBoost is putting out 5 volts, then unplug the MintyBoost and solder on the USB jack as instructed.
The solar charger has an output as high as 6V, this is a little higher than the Mintyboost is designed for but will work. The output voltage to the USB may end up at 6V. If you want to keep the Voltage out at a 'strict' 5V, connect the mintyboost to BATT not LOAD from the charger.
Follow Method 2 for replacing your solar panel's barrel jack on the appropriate page of the LiPoly Charger Guide: first slide on a large piece of heat shrink tubing, two smaller pieces (one on each wire). Tin the stripped wire leads and solder them together (red to red and black to black). Shrink the little heat shrink tubing pieces over the joints, then shrink the larger piece over the entire section for a finished look and added stability.
Test your circuit by plugging in the solar panel, then placing it in direct sunlight. The red charging light should be bright and solid, not flashing. To learn more about the charger, check out the LiPoly Charger Guide. you can also charge your battery using the mini USB jack.
Plug your phone into the MintyBoost's USB port and see it charge up!
Use two pieces of adhesive Velcro tape to secure the solar panel to your bag. Stick the fuzzy side to your bag neatly and aligned with the size of your solar panel, then mate the scratchy hook side of the Velcro to the fuzzy side, peel off the adhesive back and gently press on your solar panel. Then squish the glue joints before carefully separating the newly affixed Velcro pieces. If necessary, stitch or staple the fuzzy side of the Velcro to your bag.
We also had good luck affixing the solar panel (more permanently) with the four mounting screws at the corners. Unscrew the caps and make four holes in your bag with an awl. Line it up and screw the caps back on once the screw is through the fabric, holding it in place.