I use a Schumacher charger with the old analog gauge on the float setting for a couple of days at winterization. Once I'm topped off, I disconnect the charger. Battery switch is always off when the boat is in the garage. Top it off again in the spring.
Previous: 1993 Prostar 205
Red 1998 Ski Nautique, PCM GT40, 310 hp, , Acme 4 blade, Perfect Pass SG/Zbox.
Be kind. Have fun.