Monty, are you talking about the AGM type batteries? If so, I don't think there is much that can be done to recondition them, or at least I haven't heard of anyway. But I might be misspoken.
Another don't with the AGM battery is not to leave it out in the cold winter weather, this will definitely hurt the battery and it won't hold a charge for more then a day.
If it’s an old acid type, you may want to drain the battery and refill with fresh acid, this I know will usually bring them back around.
The other point I would like to make about batteries in a racecar environment is. Most battery manufactures will tell you to replace a battery after about a year of use. This is due to the car launching, shaking etc. This will usually knock lead pieces off the plates and build up in the bottom of the battery, once this build up starts touching the plates (and it will). It internally shorts the battery, hence, not holding a charge.
Ok enough battery 101 LOL
Sparky