AAAA Battery Holder for charging

thingiverse

I didn't want to buy a new AAAA battery everytime my Convertible's Pen dies, and NiMH has a too low voltage. So I designed this holder. I'm successfully charging (not intended for alkaline, I know) at around 10mA. This takes roughly two full days to complete though. I strongly advise against faster charging as charging an alkaline in itself is not a good idea. Charging faster only increases the risk of battery leakage. The easy way is to use one resistor and limit the current and charge it to 1.6V. For a 9V power supply this would be 740 Ohm. Add some aluminum foil to make good contact with the battery and you can charge. Remove the battery when it is charged to 1.6V. Alternatively you can attach two resistors - one on the positive or negative pole, and one underneath (in parallel to) the battery. Those resistors create a voltage divider. It will take a long time to recharge, but you don't have to check the voltage everytime. Requires: - some form of any power supply - a matching resistor - time