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Monday, August 22, 2011

DIY Solar iPhone Charger Made with Altoids Tin Is Less Than $20

By Jerry Stone

I love my smartphone. Love it! But traipsing around San Francisco, tweeting, facebooking, and foursquare-ing surely takes a toll on its battery life. With each percentage drop in battery life, it feels like somewhere a kitten has died.

That’s why I simply love this solar iPhone charger (via Brown Dog Gadgets). It’s cheap and easy to make but it also addresses my rather embarrassing stockpile of Altoids tins. Oh, and it saves kittens!

Parts Charging Circuit
2x AA Battery Holder
2x Rechargeable Batteries
1N914 Blocking Diode
Solar Cell greater than 4V
Stranded Wire
Altoids Tin (let me know if you need me to mail you a few)

Much of this is available at any electronics store, like Radio Shack. But with the cost of fuel and all of those pesky car emissions, I suggest you order a kit from Brown Dog Gadgets. The mail man is coming to your door anyway, how else are you going to get all of those Bed, Bath and Beyond coupons?

Soldering Iron
Hot Glue Gun
Wire Strippers
Protective Goggles
1. Most solar chargers use 1000 mAh internal batteries which seems ridiculous considering rechargeable AA batteries have between 2000 – 3000 mAh of current. NiMh batteries are inexpensive and pretty easy to find.

2. Because the rechargeable batteries put out 2.4 volts, a solar panel that gets at least 4 volts is required.
3. Cut off 1/3 of the wire from the battery holder and then strip some of the coating off. Next, cut off 8″ from your stranded wire, and strip the ends.
4. Wrap one of your 8″ cuts around the diode’s negative end (it’s the end with the black bar) and solder it. Solder the diode’s other side to the solar panel’s positive tab. The other 8″ wire gets soldered to the solar panel’s negative tab.
5. Twist the red wire from the battery pack with the positive wire of the solar cell and the battery pack’s black wire with the negative. Do not solder them!

6. This is the most difficult part, soldering the circuit. If you mess this up, kittens will die! Solder the positive cluster of wires to the positive point on the board and repeat with the negative wires on the negative side.
Don’t use too much solder.
7. Using some electrical tape, tape up the solar cell, maybe line the Altoids tin to avoid any shorting.
8. Test the circuit! You can use regular AA batteries to verify it all works.
9. If it works, then glue it down. Do not apply the glue with the batteries in as they might get glued in to place.
10. You’re done. Happy charging and thanks for saving all those kittens.
You can get the full set of instructions on this and many other solar projects over at Brown Dog Gadgets. If you are DIY-challenged, you can even buy this charger already made.

Follow me @jerryjamesstone or friend me on Facebook.