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
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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 ?