battery maintenance, longer life

hi everyone, I use 4 1000cca automotive type batteries on my blade test stand, also to test battery life and any ideas that might be a problem to my main system. over the last couple days I drained the batteries down to a stable 10.5 volts and recharged using a home made battery desulfator { see poorman guides } on the net. I decided to do this because they wouldn't hold a 12.7 volt or higher charge anymore. the batteries were separated and drained to a stable 10.5 volts and recharged to 15 volts using the home made desulfator , when each battery stabilized at 12.7 or better I take it as good to go. one battery needed to be charged three time to get it to stabilize at the 12.7 volt or higher, the problem battery, the one that took three charge cycles was draining the other three batteries , this has now been fixed with the desulfator and should have a good charge up ability and hold the charge as intended. these batteries have been in this bank since august 10 2015, not even a year but were used when I got them. I did desulfate them before they went into service on the test stand, this shows how short the life of auto batteries can be in a wind system, close watch and maintenance will lengthen there life , the system was then fully charged to 13.8 volts with a battery charger and connected back into the system as used in service, until the dumps were being used. then the charger was removed and the batteries stabilized at 12.82 volts like they should, my bank is back up and operating properly again, this should be done when the batteries are not taking the full charge any more, this will lengthen there life and give a better service ability while in use. food for thought. thanks for reading