Most charging systems today replenish healthy starting batteries within a few minutes then tapper off depending on the load.
If your replenishing your batteries with that much water I would suspect your system is over charging (doesnt take much)
Well it’s been the same with my first engine a Yamaha F225 that I ran for almost 2000 hours and now with Suzuki DF300APXX for almost 400 hours so far. I got 9 years out of my first set of Interstates and they were still operational when I replaced them. If that’s a product of “over charging” I don’t have a problem with it.
I run my engines 200+ hours a season and fish a lot at night, frequently with the RADAR spinning on battery power. The batteries get used, not over charged.....