On board charger in cold storage

[aquafang]

What are everyones thoughts on keeping a boat in a nice sealed up metal building but NOT HEATED and keeping your batteries plugged into the onboard charger? I live in SD So it is possible the inside of the building could see below zero temps!

[Whoaru99]

Ensure the batteries are fully charged before storage, disconnect all wires from the negative terminal of all batteries, they will be fine all winter long. Cold weather, like in winter, basically slows self-discharge to a halt.

It is actually preferable to cold store the batteries than to put them some place warm. And, you don't have to worry about freezing. A charged battery doesn't freeze until 80 below, give or take, depending on where you read.

[Esox_Magnum]

Mine sits outside covered all winter and chargers plugged in...

[Capt. H (Ret.)]

I started leaving mine in the boat in an unheated garage several years ago. I leave them unplugged from the charger but plug the on board charger in once month to put a charge into them. I do not leave them plugged into a trickle charger for fear of a fire.

[Wish-I-Were-Fishn]

Mine stay in my boat in the garage. I disconnect the charger and use a battery maintainer during the winter.

[96trigger]

I did that exact thing last year, never had a problem, batteries were fine in the spring.

[DRH1175]

Yes keep it plugged in for sure. I have done that with mine since buying my boat. On boards have a maintainer built in. As they detect a drop in voltage over time they top them off. Keeping the onboard plugged in year round is the best thing you can do for your batteries.

[Wish-I-Were-Fishn]

Be sure to top off the water before storage too.

[Whoaru99]

Yes keep it plugged in for sure. I have done that with mine since buying my boat. On boards have a maintainer built in. As they detect a drop in voltage over time they top them off. Keeping the onboard plugged in year round is the best thing you can do for your batteries.

It's really un-necessary in cold winter to keep the charger on all the time. As long as there is no parasitic load the self-discharge in winter cold storage amounts to essentially nothing.