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Need Some Help With a Project!

Posted: 2010.12.14 (04:36)
by blackson
Okay, so I have a mild interest in Renewable Energy, specifically solar energy. This interest, combined with a considerable amount of free time has led me to try and build a USB charger out of lawn lights. I bought enough lights to get 5 volts (1.5 each, so 4 of them). I doubled this amount to run a parallel line to satisfy the amp requirements of a USB device. I ended up with eight 1.5v solar cells (after painstakingly getting the cells loose from the adhesive without busting them).

Right here I'll just go out and say I have no formal education in electricity. I've taught myself how to create circuits/series and may be very wrong. Nonetheless...

I started out with eight of these cells and split it into 2 rows of 4. I soldered the rows together + to +. I then ran a wire across both sides + to - as a bridge to combine the amps of the two rows. I took a USB extension cord I bought, cut it open, found the power cords inside, soldered them with some ribbon wire for extension, threw some heatshrink on to make it nice, and hooked them up to opposite corners of the soldered cells. Needless to say (otherwise I wouldn't be here), it didn't work. I'm asking why.
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Any help would be awesome, I'm probably lining these up wrong.

Thanks!

EDIT: Oh, in my MS Paint picture, my USB cords don't go to the same corners as the ones in the RL picture do. Sorry, not intended, just wasn't paying attention when I drew it.

Re: Need Some Help With a Project!

Posted: 2010.12.14 (04:39)
by Vyacheslav
Pro-tip: Don't solder until you got everything working. Makes it easier later on. Use electric/duct tape instead.

Re: Need Some Help With a Project!

Posted: 2010.12.14 (04:43)
by blackson
I was soldering the wires onto the terminals.

Re: Need Some Help With a Project!

Posted: 2010.12.14 (16:58)
by ska
DIRECTIONS:

Try testing the wires by soldering them to a toaster.
If that doesn't work, tie up a hairdryer that's turned on with the wire and dunk it in your bath full of water.
If that doesn't work, make a noose with the wire and attach it to a roof; then play a game where you aim to jump and get your head in the noose.

SERVES 1. STIR AND ENJOY!

Re: Need Some Help With a Project!

Posted: 2010.12.14 (20:16)
by Heartattack
ska wrote:DIRECTIONS:

Try testing the wires by soldering them to a toaster.
If that doesn't work, tie up a hairdryer that's turned on with the wire and dunk it in your bath full of water.
If that doesn't work, make a noose with the wire and attach it to a roof; then play a game where you aim to jump and get your head in the noose.

SERVES 1. STIR AND ENJOY!
This is a really dickish post that doesn't even do a good job of making sense. You just lost some respect from me, sir.

Re: Need Some Help With a Project!

Posted: 2010.12.14 (23:31)
by blackson
ska wrote:DIRECTIONS:

Try testing the wires by soldering them to a toaster.
If that doesn't work, tie up a hairdryer that's turned on with the wire and dunk it in your bath full of water.
If that doesn't work, make a noose with the wire and attach it to a roof; then play a game where you aim to jump and get your head in the noose.

SERVES 1. STIR AND ENJOY!
Thanks, I'll be sure to make sure my metal wires conduct electricity.

Re: Need Some Help With a Project!

Posted: 2010.12.15 (04:31)
by taaveti
That setup will give you 3v, while your device probably wants 5v. Essentially, you'll want two rows of 4 solar cells wired in + to -, instead of four rows of two, then add a resistor to step down from 6v to 5v:

Code: Select all

[CHARGER-]-[+CELL-]-[+CELL-]-[+CELL-]-[+CELL-]
            |                               |
           [+CELL-]-[+CELL-]-[+CELL-]-[+CELL-]-[~2ohm resistor]-[+CHARGER]
A multimeter would be pretty useful to test the voltage and amperage generated by your system (it should be 5v and I think about 0.5a across the power pins- the two outer, longer, pins; a quick and easy check would be to compare it to what you get from your computer).

[edit]Fixed the alignment on the schematic.

By the way, you'll probably find you can omit the resistor, especially if your wire and/or soldering isn't perfect. I think the spec allows from 4.5v to 5.5v, so your device probably won't be harmed by 6v.[/edit]