[jclark003]

hard to say without knowing your battery and charging configuration. I would turn the switch off, and check voltage on both banks while engine running to be sure both alternators are charging. if you have low voltage with engines and charger off a battery load test will tell you if any of the batteries are below spec

I accidentally left my interconnect switch on all season and had no issues with either alternator or batteries. Both banks had the same batter type and rating.