Battery UM08A71 not charging. Got inside the battery pack without too
much colateral damage. Put a bit of current limited charge into the
cells and retried but the same.
I did not expect a computer inside a battery. 24 pin bq29312APW and a
labelled over memory? of 38 pins etc.
What I thought would be the pass powerFET was a heated fuse , marked
12AH3, presumably

http://www.cyntec.com/product/protec...543212AH3C.pdf
I've never come across the like. Looks as though the heater has failed.
So why the heater? Fast fusing of metal in overload situation if its
already close to fusing? It is designed specifically for L-ion cell use.
I assmue this PC in a battery monitors for heater failure and then
locks out from charging.
There does not seem to be independent monitoring of the 3 cells. There
is a thermistor , well something that is 7.8K sitting there. What would
be the kapton covered piece of thin ribbon going to the ,still mounted,
unobserved side of the middle cell.
Seems the powerFET is 2 off p-ch , marked A2715, 8 pin devices = NEC
uPA2715 ?