It seems like you are thinking it was overcharged, heated, and swelled.the hot battery shaped like a pillow that I took out of the last hat UPS I had. somewhere in the range of 50 to 100 percent thicker than when I put it in. it smelled like gym socks.the hat UPSs are the far side of useless. they overcharge the battery making a fire hazard you can't see.
Vague but serious allegation. Do you have any (non-anecdotal) evidence?
More likely, the battery failed, and became hot because it failed.
Yes, sometimes a battery can fail. A good charger should hopefully detect that, and account for it.
Statistics: Posted by mlepage — Sat Jul 26, 2025 2:09 pm