Sheesh Bob, I hope that 8 Gallons was a typo… 8 Quarts? Even that is a lot.
I believe that inordinate water consumption of a lead-acid battery is due to overcharging and/or high heat.
Do you own a digital VOM (Volt Ohm Meter)?
If not, get one!.. Even a cheap one ($20.00 or less) is good enough for everyday use. One caveat… Get one that can measure current up to 10 Amps or so. That spec. isn’t important for this problem, but likely will come in handy in the future for other stuff.
Voltage measurements here are directly on the battery posts, not the terminals.
Shorted Cell?
After your battery bank has sat for a day, give or take, not being charged, measure the Voltage output or across any one battery. You should measure 12.7 Volts or so. If you measure 10.5 Volts or so or lower, one (or more) battery has a shorted cell. If this is the case, the battery with the shorted cell is preventing the charging of the other batteries or discharging them when the charging Voltage/current is removed.
If this Voltage indicates a battery with a shorted cell, then there’s some work to do to isolate the bad one(s). Disconnect the + Voltage leads from all the batteries. Do this very carefully, keeping the wiring separated.
A SHORT CIRCUIT IS *NOT* AN OPTION HERE!
Put a small (10 Amps or less) charger on a battery for say 5 ~ 10 minutes.
Remove the charger and measure the Voltage of the battery. Write down the Voltage. If around 12.7 Volts +/- it’s likely OK. If around 10.x Volts or lower, it may have a shorted cell.
Repeat for the other batteries.
After a few hours, go back and read the Voltages of the batteries again. Write them down. Now you have a beginning of a log of the Voltages.
Isolate any battery that didn’t pop up to the 12.x Voltage range under the low current charging for further testing. Think probably toast here. Note the batteries that dropped back to 10.x Volts after a few hours. Possibly more toast.
For the batteries that were in the 12.x Volt range, recharge each of them with a 2 Amp charger for a day or two. They might be OK; damaged due to their lack of water, but still sorta usable.
Salvage at best:
This process is to hopefully burn off an internal battery short.
For any battery that was in the 10.x Volt range, charge them with your 40 Amp charger while monitoring the Voltage of the battery. If the Voltage soon pops to 12.x Volts or higher, Then charge it for an hour and let it sit for a day or so.
If it stays in the 10.x Volt range for a minute, or monitoring after charging, the Voltage drops back to this range, butter the toast.
There is another extreme method to try, but even the short term outcome is not potentionally good.
Id
AI
