Re-purposing Cel-phone Li-ION batteries? Answered
Excuse me Please:
I have a rather advanced Q on the re-purposing of Li-ION batteries.
the tiny battery within the SanDisk Sansa, I found to have a deplorable duration.
So in disassembling the Sansa, I discovered it had a seemingly standard 3 pin Li-ION battery (red, green, black).
Since a celphone of mine recently died, which I retained it and its battery, I decided to wire the albeit, larger, battery into the Sansa.
I was gratified in the the Sansa worked as expected, but worked for literal contiguous DAYS at a charge!!
(seems I had forgotten to turn it off in coming from the gym, to return to it the next day and it was still playing!)
Now, my conundrum:
due to the change in cellular tower technologies, and being forced to change to the newer "G" phone, I have an abundance of batteries, to which I continue to collect for myself and friends Sansa players with rewired batteries.
In that the Motorola BQ-50 battery has four(4) pins, which are suggested as the following:
pin 1 is battery +
pin 2 is a communication line back to the phone
pin 3 is a temp line back to the phone
pin 4 is gnd
pins 2 and 3 are used to tell the phone the charge condition of the battery and when the charge cycle is complete.
would anyone here have the deeper electronics knowledge to advise me which pin of 2 or 3 can be omitted and still allow the battery to be charged via the USB like the original 3 pin battery?
Thank you kindly for your time and knowledge.