Hello,
I have 48 x 12v AGM 135aH batteries and have them configured in 2s 24p. (3 x banks of 8 2s 8p).
The batteries are about 3 years old (used in a ups system)(All wired in series).
The 3 banks are connected together with 25mm x 6m Bars bars with positive feed on one end and negative on the other.
When I set them up they we fully charge and with 0.05 of volt of each other. I have 4 85/250 mppt charging these with a Mutiplus 5000Va /24 running ESS.
i have 3 x victron battey balancers 1 on each bank. They where in alarm state
I have disconnected and metered the batteries today and the batteries are at least 1.2v out.I am planning to get them all back up to fully charged using external charger
Am i expecting to much to have this amount of batteries in series parallel. They have been working great over the summer but maybe the have been getting slowly out of balance.
The only thing that has changed is I have started using a scheduled charge overnite from the multiplus.in the last 3 weeks.
Any thoughts would be greatly received.
Many Thanks