- I installed a Smartgauge battery monitor
a couple of weeks ago. After two weeks of letting in sync with the batteries, I charged them until the SGBM said 100% SOC. Then verified the Victron BMV-702 said zero Ah discharged, disconnected the shore power
and put a 10-15amp load on the system (variable due to refrigeration) let it discharge overnight to a 50% SOC charge reading on the SGBM. At that point read off the negative Ah on the BMV (-115Ah), multiplied that by 2 and divided that into the rated capacity of the 2x1800FT batteries.
I knew I was losing capacity, after being away from shore power
for so long and able to charging
them to 100% SOC as often as they need - it wasn't a big surprise. But if I can resurrect them with the charging
regime outlined above its worth a shot. I'm guessing I will need a bench power supply that lets me regulate the amps (18 amp max as 4% of the rated Ah) and voltage separately (16.6v max) - hoping I can borrow or rent one as I would hate to spend the money
on another 1 time use only piece of kit!