Step 3: Step 2

This is the tricky part. I couldn't solder the batteries onto anything. They could only touch the metal. This is because to recharge, I had to put the batteries back into the cell phone, where the plug in is. That's the reason for the tissue paper and wood.

Put the wood in the cassette case to make the batteries fit in tight so they don't move around. I also used a ton of solder so if it did move around, it would still make contact.

Once the batteries were in place, I put the tissue paper in to keep the batteries from moving around.
<p>Cell phone batteries have built in charging circuitry to prevent over charging and discharging. </p>
I like the recycle thing, I think hair ties that are about 1.5in in diameter would work and last a lot longer than the bands. Just a suggestion. Doodado
Those hair ties would work good, they look about 1.5 inch in diameter and last <br>Longer than the bands. Just a suggestion. Doodado
How did you wire the batteries to charge them/ power the leds, cant find anything on how to do that <br>
Now what would be even cooler (especially for commuters like me) would be some way at the end of the day I could just plug my cell phone to my light system via the USB port, and power the lights right off of my phone. I have to charge the phone every night anyway!
Actually Sladek is only partially right. It is not a good idea to drop lithium batteries below their minimum voltage nor charge them at too high a voltage. However it is common for cellphone batteries to have current regulation of some sort built onto them. Take one apart and see for yourself there is circuitry there to regulate discharge and it will cut power once it drops too low. The sensor the cellphone reads is just an additional safety measure to watch the temperature.&nbsp; I have used cell phone batteries in many projects as a power source. I have seriously abused them and charged them with chargers never meant for that purpose. I have never had one explode, swell, or leak. I think the dangers of exploding lithium batteries has been over hyped.&nbsp; The only real danger comes from dead shorting a fully charged cell. That will lead to extreme heat and a possible fire/explosion if the batteries on-board circuit doesn't burn out first.&nbsp; <br />
Cellphone batteries are lithium based, and with lithium batteries it's dangerous to drop them below their minimum voltage. A full charged 3.7V battery is roughly 4.2V, once it disipates down to 3.7V, it's minimum safe voltage, the battery can swell and explode, without the need for ignition. The way all lithium polimer gadgets overcome this is by using a cut-off circuit that kills the power at minimum voltage. Overcharging about 4.2V is just as dangerous. Just my 2 cents
cell phone batteries are awesome to use
very nice, this fixes the problem i was having, i was using a litlle kid's electric toy car's battery, but those are expensive
oops, I had it setup with the switch before the resistor, but it should work either way.
Nice. Any pictures of it in the dark?
I'll post one when I get the chance to take it.

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