I was inspired by the excellent instructable "Rain or shine solar charger" by Blondietheblond, but wanted to avoid sewing, since I don't have a machine. So this is the result.
Step 1: Gather the stuff you'll need:
Most backpacks have enough possibilities to attach stuff. Mine provided these ribbons on the back. No idea what they are supposed to be used for.
1) for the solar panel:
- 4 Encapsulated 2V/200mA solar panels (Velleman SOL4).
- Self adhesive pads for cable ties (3M Scotchlok Ab02).
- Nylon cable ties to fit the adhesive pads above.
- Velcro adjustable cable binders (Tesa 55236-00000, 12mmx20cm).
- Heat shrink tubing.
- Electric wire (capable of carying 0.5A is more than enough).
- Connector to go to the battery box.
2) for the charger/battery box:
Parts list for this is less critical, so improvise. There's an explanation with important details ahead.
- Small plastic project box.
- 4 AA-size NiMH batteries (GP 2700 series is ok, see further).
- Battery holder .
- Two 2-pin panel-mount connectors of some sort.
- Components (see further).
...and some tools:
- soldering iron.
- sharp knife.
- drill for making holes in the project box.