Both of my boats have new smart battery chargers. The Sea Ray has they kind that will even equalize the charge going to each bank. If I can keep the battery chargers plugged i for the winter and connected to the batteries, Is there any point in removing them from the boat and putting them in the basement? What do others do and if you leave them on the boat, what kind of battery charger do you have?

I have not removed a bat for the winter in wither in a long time, since smart chargers were invented. Turn bat switches off and I'm good

Back when I had a boat that the batteries were easy to pull, and the boat was statically stored outside; I would pull them and put them inside stored on wood, (not on concrete) with trickle chargers attached. The last few years, I have just left them in the boat, and plugged the boat in for about a week a month to keep them topped off.

I've seen what a bilge looks like when a battery blows up what a mess, I leave them in the boat but not on a charger with the onboard heater on.

Mine sit in the boat all winter long with the battery switched turned off. In the spring they get a few hours trickle to top them off and they are good to go.

Same here. Plenty of voltage when spring hit this year with (2)4 and (2)6 year old batteries. I can't unhook my batteries AND open/close my hatch without great effort. Thing is too friggin heavy. If they are dead in spring, plug in onboard charger until hatch will open.

Battery switches to OFF
Remove cables from batteries
Clean the batteries with baking soda/water solution
Top them off if they are fillable
Charge them then put the charger away
Leave them in boat and forget about them until spring.
Doing this for 30 plus years in a northern climate and the boat stored cold. Batteries replaced appx. every seven years.

as long as they are on a smart charger you should be fine, make sure water is full, if you remove them the old saying(my dad swore by it) do let sit on concrete is been proven not true.

It's too cold here in Michigan and my batteries come into the basement. I pull the batteries out of 3 Mustangs, the lawn tractor and the boat. 6 batteries come indoors every winter to extend the life of them.