Should I take batteries out winter & put in basement on a board. Or leave in boat & plug in shore power for battery trickle charger every so often?

I have never pulled out batteries for winter. No shore power me. I check the voltage once a month or so and charge if needed. I have had a boat in storage for 5-6 months before and the batteries still had a good enough charge to start the boat.

I leave them in but they are connected to a BatCat charger all the time.

I leave them in. Unheated storage, hooked to a battery-tender. Never have a problem.

Leave in with battery tender and no problems. I've done it for about 8 yrs now.

I have found that my batteries are good for 3 - 4 years if I leave them in the boat all winter unattended. And, the boat is stored outside so it does get cold.

I take mine out and put them in my warehouse so I can keep an eye on them and charge as needed. - Jeff

I put mine in the basement on a battery tender. Came in handy last year when the battery died in the tractor and I couldn't snow-blow!

I have my three in the basement on a shelf, charged them when I pulled them out, I'll look at them again in early February, then again when they get re-installed in March.

They have a 3 year full replacement, and I keep good records and receipts........

Sounds like I could go either way & be fine. Generaly in the past I've pulled them & set inside. Thought this year I might want to peek at this engines a few times, so easier to leave in.
Thought I read one time that its the minus 10 degree days that are hard on batteries. Have not had too many of those in recent yrs.