Simple, Cheap MP3 Player Solar Charger

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This is a really simple tutorial on how to make a solar charger for your MP3 player. This won't work with an iPod touch (The iPod ignores it, it's not an apple product), but should work with most generic players. I use it for my CreativeZen player.

I bought my solar cells HERE. It's the best prices I can find, plus free shipping!
This panel charges @
5.13 Volts
.8 amp to 1 amp; in full sun

Because MP3 players have built in battery savers, there is no need for an electronics board or battery sensor. It's physically impossible for the solar cells to spontaneously produce a higher voltage. If the voltage drops (for whatever reason) the MP3 player automatically disconnects the battery.

MP3 players automatically disconnect the battery before it overcharges
MP3 players will not discharge into the panels, they have built in diodes.

Putting it simply, the very worst that could happen is that it won't charge the player.
But I still have to say: do this project at your own risk :)

Step 1: What You Need

1) 9 x 1 amp, .57 volt solar cells. I bought mine HERE
2) Tabbing wire or fine electronics wire. I bought mine HERE

3) 8 x 10 cheap plastic picture frame from Wall Mart
4) USB extender with female USB adapter. $1.00 at Dollar Tree.

Wood/foam core,Solder, flux pen/ normal flux, soldering iron, and soldering skills :)
I recommend you wear latex gloves when you work with solar cells. Fingerprints look bad...

Step 2: Solar Cells

You'll notice these aren't the EXACT cells I used. I bought some larger cells from this same seller about week ago, for another project. I had a few of these large cells leftover, so I cut them down to the right size myself. The cells I used are the same size as the ones in the link, with the same specifications. The seller is a really nice guy, very trusted. I've never had a problem with my orders (I've made a few very happy purchases :) )

I recommend that you also buy 'tabbing wire' . Tabbing wire isn't totally necessary...regular wire works fine, but it's harder to use. Tabbing wire make soldering way faster and way easier!

Simple explanation:
The only unusual item you will need are solar cells. All solar cells put out .57 volts, no matter there size. The amperage is proportional to the size. Larger cells equal higher amperage. You are going to wire 9, 1 amp solar cells in series to produce 5.13 volts and 1 amp.

Complicated explanation, you don't have to understand all of this:
An electronic device will only take the amperage it needs. If the device needs 2 amps and it charges off 8 amps, it will only take 2 amps. You could charge 4, 2 amp devices off 8 amps.

For this project, you will need to make a panel (a bunch of cells) that puts out 5 v and 1 amp. Since each cell puts out .57 volts, you will need to wire 9 of them in series to reach 5.13 ( as exact as we can get to 5.00 volts). If you wire 9 cells in series, each large enough to produce 1 amp, you will get a panel that puts out 5.13 volts at 1 amp.

Got it? :)

Step 3: Soldering

I'm not going to go into depth on how I solder, other than how my soldering iron is set up. There is a simple tutorial on how to solder solar cells here. If you're still having trouble, Google has the answers!

My soldering iron has a tinned tip. The solder sticks to the tip of the iron, so I have it when I need it. No fooling around with solder wire here!

I just touch the tip of my iron to the lightly fluxed panel and tabbing wire, and bam! Instant solder joint.
Oh, and I use regular flux. Don't use too much, a little goes a long way.

Solder the cells in series. That mean positive to negative, positive to negative, and so on. The top of the cell is the negative end, and the bottom is the positive end.
The second and third picture better explain this concept.

Step 4: Making the Frame

After you solder together your cells, you need to protect them in a frame. You could build one out of wood, or you could modify a picture frame.

$2.00, 8x10 plastic frame with glass pane: Wall Mart
The following steps are in related to the pictures, in order:

-Remove the glass.
-Cut out the cross shapes structural support.
-File the inside corner, all the way around. You are trying to make a weak spot so you can break out the inside wall.
-Break out the inside wall. It is brittle plastic, it will break off in chips.
-The final image is what you should now have.

Step 5: Support Board

You need to cut out a board that fits inside the frame, as if it was a photograph originally intended for the frame :). You are going to glue the assembled cells onto this.

I used wood, but foam core will work also.

Step 6: Gluing the Cells

Use silicone caulk to glue the soldered cells onto the board you just cut. Solder the odd cell after you glue it all down.

Step 7: Leads

Drill 2 holes in the board, and solder the positive and negative lead to the cells. Feed the 2 wires through the two holes, and glue the board into the frame.

In order to better protect the wires, I put a bit of epoxy on them.

Step 8: USB

Solder on the USB connector to the appropriate positive and negative wires. When you cut apart the USB, you will see 4 wires...you only need the red and the black wire. The red wire is positive, solder it to the wire coming from underneath a cell. Solder the black wire, the negative wire, to the wire coming from the top of a cell.

Glue the USB connector to the picture frame with epoxy. It needs to be a strong joint, or it'll get broken off. I put epoxy on the connections for further protection.

Step 9: Installing the Glass

Pop the glass back into the frame, and shine it up with a soft cloth. Clean glass means better light transmission, and that means more efficiency of the cells.

Only use this panel in full sun, do not allow a shadow to fall on any part of the cells. A shadow on a cell can cause reverse flowing current, and this could damage the cell. Also, a shadow will slow down the charge time and potentially cause the device to undock and stop charging.

This panel charges my CreativeZen player just as fast as the computer!