I purchased a nice battery charger a while back and noticed that it had a “battery recondition”(desulfate) option. Since I had about 4 power sprayer batteries that were weak, I decided to run them through the cycle. It is too early to tell if it is a total recondition or to what percentage of “new condition” it has brought them to, but it seems to have worked really well so far. After I use all batteries on a full day, I will return with an up-date.