My house bank seems to get a bit weak after two years. I'm using conventional flooded deep cycle batteries, and prior to this I used AGM. They do take a charge but I'm sure they don't have the AH performance they're rated. I have a battery monitor attached to the house bank. I'm making this judgment based on unusual battery monitor readings, not based on individual battery tests. For example, yesterday my monitor showed the house bank at 82% charge and 12.1v at-rest, before I started the engine (that's incongruous). Soon after starting underway I was only getting about 15-16 amps charge current, and after about 2 hours I checked again and it showed about 13.8v and acceptance at around 7amps charge current, and about 87% charged.

Must be something in my setup.

I'm using a stock Volvo-Penta (Valeo Rhone) 60a alternator with internal regulation. My solar charge controller is a Morningstar SunSaver MPPT 15 with default settings and remote temperature sensor. I have three banks: Engine start single, house (225ah), and windlass/thruster single. The solar charge is connected to the house bank, the engine battery receives the alternator charge. There is a battery combiner connecting the house bank to the engine start, and another connecting the house bank to the bow battery. Each battery combiner connects when one side is above 13.2, so they are only connected while receiving a charge and a low bank won't drain the others below 13.2.

I own a load tester that I've never used, but I think it's time to drag it out. Maybe I have a marginal connection somewhere. Thoughts?