I have a battery issue too, that I’d like opinions about.
I just bought 8 new series 31 120 AHr deep cycle marine batteries in August (while in Maryland). They were kept fully charged with solar before we headed S in late Dec. After only a month, they are not acting like 120 AHr batteries. They stay charged fully during the day with solar (900watts) but at night they discharge to ~24.7V and the monitor says I’ve only used ~45AHrs. I reset the monitor at dusk when the solar is no longer charging. 24.7V should be about 70% of capacity. That is where I’d like to set my minimum voltage before recharging, in the interest of battery life. But my 480 AHr battery bank shouldn’t get there until I’ve used 30% of capacity, which would be about 160 AHrs.
Am I thinking correctly about that?
I checked the batteries which consistently showed low specific gravity of 1.225 to 1.250 (in the”Fair” range). This didn’t change appreciably after running two equalization cycles with my Victron Skylla charger. It does seem that the batteries are a bit better in that they are now at about 24.8 V just before sunrise.
What do you think is going on here? Should I just keep running equalization cycles until the SG gets back to normal?
Thanks for any advice, thoughts, etc in advance.
Kent & Iris
Still in Ft Lauderdale (We’re calling it Hotel California...you can check out but you can never leave.)