This has been good info and I didn’t expect so many posts on it lol. I always made it a habit to charge my batteries any time I wasn’t using the boat on the water. My dealer suggested I try and make it a habit to alternate using the batteries each time I go out. After reading the post above by Goose and I can understand the reasoning. For me I will just keep charging like I’m doing and will also alternate batteries each use (if I can remember lol) just so that the alternator gets a chance to charge both from time to time. I did not know it wasn’t recommended to not use the batteries while also charging. I’ve done this on my last boat when “garage boating” listening to the stereo while cleaning or whatever and never had issue but also didn’t have a trolling motor or sensitive electronics. From now on I’ll just leave the charger unplugged next time I want to listen to the tunes while in the driveway. Again this has been some good info to read and thanks everyone for sharing!