U do NOT need to isolate the batteries to charge them with a 12 volt on each one, in fact If u have a few batt chargers that are say 4 amp and u want to charge a battery faster u can put more than one charger on each battery as long as they do not total an output of more than 12 volts for each batt, have done all this plenty of times, any batt tech will tell u this is true too, go to batterystuff.com , U should have a desulphater also, U can put a 24 volt on board ,i have on each truck but i am going to put a 12 volt on board on each batt , that is the ultimite, if u use just a 24 volt it is more than fine, but if U want to get into it and get the most out of batts , u need to take em out at least once a year clean em and dring em each up to charge by a 12 volt and rotate them the last batt that was getting juice to the first and so on, u will find there is always a lazy bettery in mil trucks because the last batt getting the juice is always a little low because they do not fully charge them in service and it causes desulphation and the result is not holding a full charge, sulphated batterys take a charge very fast but it is a surface charge and does not last. It is just inexperience not knowing U can charge all your batts in the truck hooked up, Nothing wrong with that , I learned from calling all the manufacturers and doing what they say, not listening to the guy down the street at the garage , they do NOT know, U need to call the source for the correct info, And recently i needed to move the 925 and it was way cold and i did not have the chargers on , So I needed juice , so i slaved it, plugged in the on board 24 volt and pulled out the 4 battery at a time charger/maintainer and hooked one lead to each batt, and that is not only fine it is recomended in times of a needed fast charge. nothing got warm no fuses blew, becuase it is impossible.Now like i said do not excede 12 volts in each batt, that is over charging, and will cause damage.
