Here are the 42 battery cells I'm re-homing from the scrap pile at work. They're 4,400 mAh, 3.7V, Li-Ion batteries, with a protection circuit built in. They're not the fanciest battery in the world, but at the price I got them at (free), they're pretty unbeatable!
The first thing to do was to find out the maximum current they could put out. The protection circuit in these units effectively limits the amount of current the battery can discharge. The reason being, if these things let out too much current, they will heat up, and become quite dangerous. The downside is the current limiting circuit chokes the maximum power limit of the bike.
According to the battery datasheet, the maximum discharge current is 2.4~4.5A. I decided I better test this out, and see how much juice I could pull out of these suckers. I bought some high current load resistors from Trademe for a few bucks, connected them to a few batteries, and started measuring the current with a multi-meter, and an oscilloscope.
|High current resistors (3 and 5 ohm)|
Manufacturer: Golden Cel Battery Co. Ltd.
Max discharge current output: 3.6A
Nominal voltage: 3.7V