FAQ:  Battery deeply discharged – what to do?

By mistake I have deeply discharged the 12V LP battery.  When I discover this situation, the voltage of the battery is < 1.5 Volts. How can I restore the battery?

Honestly, there is no way to restore the LP/LFP cells and batteries if there were deeply discharged. (Bellow 2.5V per cell or 10V per 12V battery.) If the battery is deeply discharged the internal structure of the cells is damaged. There is no way to get the battery back. The battery must be replaced with another battery.

Trying to charge this kind of empty battery will only result in even bigger damage and the battery will swell and release the gases!  Never try to “correct” the problem by swift charging!

The only option is to disconnect the battery and wait for some time (hours/days) to see if the voltage returns back to the minimal level.  If the voltage returns by itself, there is still hope that such battery may be charged. However this charging must be done with very small currents (0.1C or less) and the charging must be monitored.  If the voltage does not return and stays low, the battery is dead.