I have six group 31 AGM batteries, but in my case they are for propulsion
purposes (connected in series, as my system is 72V). I charge them with a QuickCharge MB1210X6 (manufacturer's website: HOME
), which allows for each battery to be charged independently. It has settings for two AGM charging profiles (plus several other profiles for other type of batteries). After consulting with the manufacturer which setting to use, the bank has been working flawlessly for over a year.
There is plenty of information available online about charging multi-battery banks and the effect of the different loads they are subject to due to the resistance imposed by the wiring
(I assume you have the six batteries in parallel and the charger would charge them all concurrently).
In my system (again, series), when the batteries were new, they all reached absorption and float mode at the same time. One year later the charger shows that the “more positive” batteries reach each stage faster than the “more negative” ones (it happens in order, 1 to 6, and with the same timing difference between contiguous batteries, which I read as all batteries being OK).
As expected, the “more negative” batteries are working harder, as they are “fighting” the resistance of the ones closer to the positive end. This charging time difference is of a couple of minutes at the most, so for the moment I will not make any changes, but I think that in the near future I will switch batteries 1 and 6 (the most positive with the most negative), and later 2 and 5.
With this, my suggestion is to check if there are significant differences in wiring
lengths between your six batteries and keep an eye on the charge condition of the less and most “burdened” batteries, it may be worth switch their position in a couple of years.
BTW, I keep the charger always connected with the batteries receiving float charge all the time (same with the house bank).