I have been working with two 12 V lead-acid batteries in series. Accidently, we kept them turned on for a day or two and one of them drained to ~3 V and the other to ~8 V.

I immediately charged them, but they get charged and drained super quickly. I read about recovery charge on this forum, but my charger doesn't seem to have a recovery charge function.

Also, sometimes it gets charged to 16 V on balance charge. Can those batteries be recovered or should I replace them?

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    \$\begingroup\$ Do you mean "lead acid"? They fail rapidly when heavily discharged, and most likely now need to be replaced. \$\endgroup\$ Apr 9 at 4:22
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    \$\begingroup\$ Lead acetate you say? Perhaps you could turn them into solar cells sciencedirect.com/science/article/abs/pii/S2211285519310948 \$\endgroup\$ Apr 9 at 4:48
  • \$\begingroup\$ Sorry for mistake I meant lead acid battery \$\endgroup\$
    – mrbeast
    Apr 9 at 17:05
  • \$\begingroup\$ Depends. If you charge them up, preferably to 16 V, let them bubble a little and refill any lost water (distilled), they may very well be serviceable. Do you have access to any ESR or load tester? \$\endgroup\$
    – winny
    Apr 9 at 17:11

1 Answer 1


There was no way to recover it. That battery went dead. Used it for other minor application and bought new battery for my original application.


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