Cheap circuit to drain batteries?

[johnny13oi]

Hey guys, how do you build a circuit to drain the batteries so that I can recharge them again? I heard that you want to drain the batteries to .9V and that would be considered as a full discharge. Someone told me you can just put resistors and itll drain the battery but what value should I use to do that? I have Rayovac hybrids and they don't seem to work any better than my normal 1700mah energizers and I am guessing I need to break in the batteries.

 

[matrixshaman]

A resistor would be cheapest but you'd have to monitor it with a meter so as to not drain them too far. The value you choose would essentially determine how fast they drain. I'd say you don't want to drain them too fast. You may want to get some more expert help here but I'm calculating maybe 15 Ohms for a 1.5 Volt battery discharging at 100 ma. Basically divide the milliamps you want to discharge at into the battery voltage and that will give you the Ohm value. And you may want a fairly high wattage resistor to keep it from burning up. This might be too slow if your in a hurry so maybe some more knowledgeable folk will chime in here.