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Brav · 11-27-2017, 07:02 PM

I have a PD4655 charger which is always plugged in, and a Victron solar MPPT.. batteries are always stored topped off. However I did notice a lot of corrosion on the negative terminal. I cleaned it and checked water before the trip. Water seemed fine, 1/4" above the plates.

Just got back from a 4 day boondocking trip in Sedona All went fairly well, except on the last day/night, we used a bit more power than normal, and left the stupid awning light on over night.. but it only draws 1.5 amps or so.. so maybe Temps were 80 during day, 32 at night. Furnace was on a lot. First two days, I got it near 99% charged or 100% each afternoon with solar. But Voltage alarm was going off on third night, voltage dropping to 11.5V when the furnace was going, at around 3AM, pulling 8.5 amps total. Was set to 58 deg. Showed consumed AH at 102 of the 230 something I should have. With near no load, battery was at 11.74V.

I have charged the batteries many times, and the highest resting voltage I can get is 12.65-12.69. Seems low..

Anyway, are these things toast? I should be at 60-65% state of charge, and voltage is well below 12v.

carl2591 · 03-28-2018, 07:37 PM

have you check the Specific gravity of each cell to see what is going on?? might be a bad cell in one battery. that can drag everything else down.

being only a year old is there warranty left?? if the other battery is good replacing one but be OK especially if SG is good on the other one.

rmkrum · 03-28-2018, 07:41 PM

If the batteries are sitting at 12.6 volts or more AFTER being charged and allowed to sit for 2-3 hours with NO loads on them, they are at 100% charge as far as a terminal voltage reading will tell you.

A specific gravity check with a good battery hydrometer is the best check for bad cells, etc.

Bad cells happen...

I darn near ruined a set of GC-2 batteries by overcharging with an airstream OEM single-stage charger, but was able to recover a fair amount of capacity by using a better charge system (Solar). ALL the cells had boiled way low, but refilling woith distilled water and getting them started charging with a jump box recovered good enough to keep the AS in storage for now. When I replace my convertor with a 4-stage one, and a new set of batteries we should be good to go again.