Recovering bad sealed lead acid batteries

~8hrs later charging at 900mA. Battery cooled in water bath. The top seemed to be heating so I removed some of the excess electrolyte as it was clearly overfilled, down to the plates with a syringe and a cut of piece of spray can squirty tube. Got several ml out of each cell, so there's some acid gone. I've kept it to put it back in if it works or for disposal. Check of off charge voltage after settling down period several times today was not good, 10.4, 10.5, 10.8. The only glimmer of hope was that after all this excess charging the off charge voltage was 11V, so that is slowly increasing and that the battery is able to deliver plenty of current on discharge. If it was not I would abandon this experiment. Its possible the conversion of damaged plate into active material is taking more energy than expected, if that is occuring.

Yeah this battery is dead. Came back this morning to 9V across it with 200mA charge rate, so it has discharged itself. I have probably killed it even more with the high charge rate.

Experiment ended: FAIL

Haha yes. Well in light of this next time I will add drips of water very slowly and avoid filling the cell. I also bought a desulphator cheap from china and will try the slow way. I have an old but unused car battery that probably needs some ... uh.. 'love'.