I do the same thing and run my pumps with engine off. I only have 3 pumps tho since I have Ramfill. 1 for bow and 2 for rear lockers. I also have 2 banks....and added a 3rd battery on my accessory side but ran the pumps the same way before I added the 3rd battery last summer. Definitely no issue running all the pumps with engine on tho I would think, especially if you are keeping batteries on a smart charger when off the water to keep them topped off so the last (and check the water level in batteries at least once a year, add distilled water if low). Keeping water at right level and the charge topped off, will maximize the life