I just installed the 18V setup from Gruber Power. I have an automotive battery charger. It has 6V 6 amp, 12V 6 amp, and 12V 12 amp. Is 6 amps too much for the Gruber batteries? If it's ok, how long should I let the charger connected for?
I came across a 12V 2amp charger. How long should I let the battery on the 2am charger? I am just charging the 12V Gruber battery, not the 6 and not both at once.
12V 12AH could be charged at 2amps for 6-8 hours.
You can go to c/4 if you want, but I wouldnt (12AH at 3 amps for 4-6 hours)
I would set a timer. I used a christmas light timer. Turned it on checked the time and hooked an off switch (those little tabs you put in it) to 8 hours from now... That way in 8 hours it turns off and take manual intervention to turn back on.
Check the voltage under load as well. a fully charged 12V battery should put out 12.7V under load. So hook up a DMM to the wires from the batt, press the gas for 3 - 4 seconds and record the lowest setting. Is it below 12.3V? Charge some more.
a 12V battery is dead at 10.5V using the above test.
I like the following information (site noted below) State of Charge 12 Volt battery Volts per Cell 100% 12.7 2.12 90% 12.5 2.08 80% 12.42 2.07 70% 12.32 2.05 60% 12.20 2.03 50% 12.06 2.01 40% 11.9 1.98 30% 11.75 1.96 20% 11.58 1.93 10% 11.31 1.89 0 10.5 1.75