Originally Posted by Jgntch
When we bought it last fall the original owner did mention the batteries could stand to be replaced. Would them going bad cause the “over” charge?
I'll go out on a limb here...
If the batteries are at the end of their useful life, then for a number of reasons it could take more power to bring them up to "full" - where full is defined as the batteries not taking any more power. But the electronics that measure % of charge only sees what is going in, and doesn't take into account "why" more power than normal is going in.
A theoretical example. A good 100 Ah battery will need 110 Ah to go from empty to 100% full. A defective one might need 150Ah but the charge counter sees the extra 40 Ah and claims 140% charged.
With out knowing any of your specifics this is all speculation, but perhaps a formal "load test" of your batteries is in order.