My batteries are dying.

Steve Bode

I just purchased new AGM batteries in January. They were working great for months. I kept checking the battery box of heat or smells. Everything looks great. I have a new Sterling ProChargeUltra 30a charger installed. When I replaced the batteries, I set the charger to use the AGM profile. The charger seems to be working fine. When I power it up, it'll read 30a for a while and then float down to about 3-4 amps and eventually I get the float light. For months, I have been checking the original Magnetronic DCC 4000 battery meter to monitor charge. It was telling me the batteries are at 100% and the Ah were close to 400. 

Then, about a month ago, the percentage of charge and the Ah began to read lower. I would check the charger and it would say that it's in float, but the percentage on the meter was dropping every day. 70%, 60%, 50%. My charger has been plugged into the dock for 5 days and the meter reads 40% and the charger is in float. The voltage reads 25.95v. 

Should I panic? Am I doing something wrong? Is it possible that the engine alternator has been overcharging my AGMs? Any advice?

Steve Bode
Sailing Vessel Intention
Amel Super Maramu 1994 #117
+1 415-710-6659

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