Never slow it to go below 12v and recharch at a higher charge most altinators won't get over 14v but you can get recondition recovery
On sums chargers this removes the sulfate from the plats and turns it back in to sulfurick asid
Even a battery that has Ben run down to a very lo volteg can be recuverd it sulfation is not to huge
The most important thing is to recharge as soon as possible to prevent the sulfate from becoming basically to hard to remove lead sulfate is sof in the early stages but becomes more difficult to remove with time
Exercising the battery will help to remove the sulfate
Bill