Your boat wiring site is great. It’s the only one I can find that really gets in-depth on these topics. Good job!
Is this possible or could there be a problem with the charger, wiring, etc? The system seems to be about five years old or so as the stickers on the batteries are from 2007.
Any help would be great….
The easiest way to troubleshoot your boat wiring is by swapping your batteries.
If the problem moves with the battery, then the battery is the problem. If it doesn’t, you may have a bad leg on the charger or a hidden bad connection.
Since the system is five years old, my guess is the battery is the problem.