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Update: I stopped tossing swollen laptop batteries and started reviving them with a bench supply
I used to swap out any battery reading under 9 volts on a ThinkPad T480, until a guy at the shop in Reno bet me lunch I was wrong. I set my bench supply to 0.1 amps at 11 volts and watched one climb back to 10.8 in about 40 minutes, and it held for a full workday. Now I try a slow revive before ordering a new cell, but I still won't do it on anything puffed or hissing. How do you all decide when a battery is too far gone to bother?
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max_schmidt7712h ago
The bench supply trick works but 0.1 amps is pretty low for a T480 pack, those are usually 3 cell or 6 cell and the BMS wants to see a certain voltage before it will even let the charge circuit wake up. Once you get a cell that reads below about 2 volts per cell, the copper shunts inside start to dissolve and you get internal shorts that no slow charge will fix. That 10.8 recovery probably means your pack was just asleep from the low voltage cutoff, not actually dead. A real goner will either refuse to climb at all or sag back down within minutes of coming off the supply.
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