Wiring the panels to the battery.

Step 6: Wiring the panels to the battery.

Solder wires to the positive and negative terminals of the solar panels, with the capacitor in between (I used a ceramic one, so it doesn't matter which way it's connected. If you use a different kind, check the polarity).

Solder another pair of wires to the positive and negative terminals of the battery; you will have to cut away some of the tape. After you are done soldering, put some tape back so it won't short out against the back shielding of the device.

Put some tape beneath where you want to put your IC so that it doesn't short out against the EM shielding.

Now you can solder the wires from the battery and the solar panels to the IC. Follow the nice schematic attached to this step: the negative terminals of both the battery and the solar panels are wired to pin 2 (GND), the positive terminal of the solar panels is wired to pin 1 (USB) and the positive terminal of the battery is wired to pin 5 (BAT).

Place the board somewhere where it's not in the way of anything when you put the e-reader back together and put some more tape over it to fix it in place.

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lhospadaruk says: Aug 4, 2011. 11:57 AM

Why not just wire the solar panel to the USB power and let the built-in charging hardware handle things?

flapke (author) in reply to lhospadarukAug 5, 2011. 12:46 AM

Because if you apply 5V to the USB connector, the Kobo turns on or goes into charging/mass storage mode if it's already on. It would be pretty annoying to get interrupted every time a little light falls on your e-reader, not to mention that it would be less efficient.
It might be possible to do this to other e-readers, though.

lhospadaruk in reply to flapkeSep 7, 2011. 7:12 AM

That's definately true, I thought at first that maybe it only goes to usb mode when it can actually talk to a usb host, not just when it gets usb power, but that's not the case.

ksilverwing in reply to flapkeSep 6, 2011. 3:37 PM

In that case, couldn't you just have some kind of cover on the solar panels so that they're in the dark while you're using the ereader, and then you open the cover when you want to charge it?

ewookie in reply to flapkeSep 6, 2011. 2:32 PM

i don't think he intended to leave it plugged in...just when charging. it is stupidly inefficient that these type devices turn themselves on when you plug them in to charge.

eandresen says: Jun 16, 2011. 9:37 AM

That battery looks like a LiPo

flapke (author) in reply to eandresenJun 16, 2011. 9:48 AM

You are correct, sir.