Battery Storage In Winter

[Jolly Green]

New to boat ownership and am in the process of winterizing this weekend.  Everything has been pretty straightforward so far but I have read conflicting views on what to do with the batteries.  I know to make sure that the electrolyte is topped off and that the batteries are fully charged, but is it better to store them in the basement or in my unheated garage?  I'm in WI, and all the Norwegian farmers around me swear that this winter is going to be every bit as cold as last winter, sub-zero temps and all.  If it's OK to store them in the cold garage, is it OK to charge them there as needed or should I bring them indoors and let them warm up before I top off the charge?  Any help is appreciated.

[Wayne P.]

New to boat ownership and am in the process of winterizing this weekend.  Everything has been pretty straightforward so far but I have read conflicting views on what to do with the batteries.  I know to make sure that the electrolyte is topped off and that the batteries are fully charged, but is it better to store them in the basement or in my unheated garage?  I'm in WI, and all the Norwegian farmers around me swear that this winter is going to be every bit as cold as last winter, sub-zero temps and all.  If it's OK to store them in the cold garage, is it OK to charge them there as needed or should I bring them indoors and let them warm up before I top off the charge?  Any help is appreciated.

What do you do with your tow vehicle battery?

[Jolly Green]

Errrr... it stays in my tow vehicle that I drive around all winter.

[slonezp]

Battery electrolyte/water freezes around -50* on a fully charged battery. You can leave the batteries in the boat as long as there is no drain on them. If you want to bring them inside and sit them on the rug in front of the fireplace and offer them eggnog, that's ok as well.

[slonezp]

All kidding aside, a fully charged battery in a cold ambient temperature will lose very little of it's charge. Todays computer controlled motors WILL have a parasitic drain on the battery so it's best you disconnect the positive lead at the bare minimum. I've stored my batteries inside during the winter, in the hall closet for the last 10 years and top off the charge once a month  

[Jolly Green]

Point taken, lol.  

[Jolly Green]

Well, we're talking a '93 Evinrude 25 tiller, so not too worried about computer controlled anything. Thanks for the advice.

[gulfcaptain]

Keep them off concrete, store them on a board. The boat I work on we have to keep extra batteries for emergency reasons(bad to loose 24v offshore 100+miles ).  Have them stored in a wooden create/pallet and put them on a trickle charge once a week for 2hrs.  Keeps the extra battery charged and ready if needed.  If you store them on the concrete without a piece of wood or the battery box, you may be buying a new battery next spring.

[Jolly Green]

  If you store them on the concrete without a piece of wood or the battery box, you may be buying a new battery next spring.

 

Interesting. I was planning to leave them in the battery boxes, but why is that?

[gulfcaptain]

Well I know if I store the batteries on the vessel I work on on the Aluminum deckplates they seem to loose their charge.  Same go's for the concrete. If you store them on the concrete they seem to loose their charge and the cells go dead.  Don't know why, been told by mechanic's that if you store them on concrete you will kill the battery.  I have no reason to argue or ruin a perfectly good battery to find out if they were lying to me or not.  Much easier to play it safe and stick a piece of plywood or some 2x4's under it.

[slonezp]

I've heard the concrete thing as well. Don't know if there's any truth to it.

[gulfcaptain]

So who's up to buying a new deep cycle battery and leaving it on the concrete during the winter and see if it's good next spring?  Then we can get to this mystery and see if it's true.

[Lewi]

Mine stay in the garage all winter on a shelf with a trickle charger/maintainer on them.

[paleus]

Putting batteries on a concrete floor used to be bad when battery cases were made from wood and early rubbers. Modern batteries in plastic cases can be stored on concrete with no ill effects.

http://www.homepower.com/articles/solar-electricity/equipment-products/ask-experts-batteries-concrete

I just keep mine in my garage with a maintainer hooked up.

[wnybassman]

The past couple winters I have left them right in the boat, making sure the charge is topped off and everything is disconnected from them.   I have not noticed any ill effects from doing so.   The 16 years before that I would haul them out and put them in a heated area, definitely a p.i.t.a.     I'll keep leaving them in until something tells me not to.

[Jolly Green]

OK, guess I'll be leaving them disconnected on the boat. Thanks for the help, guys!

[Wayne P.]

So who's up to buying a new deep cycle battery and leaving it on the concrete during the winter and see if it's good next spring?  Then we can get to this mystery and see if it's true.

I do it all the time. I typically have two in my garage siting on concrete and then those in my aluminum boat that all stay in my unheated garage during the Winter.

The concrete thing is a myth now that was started when batteries were not made like they are now. The plastic battery case is a better insulator than rubber.

Cold is cold no matter what surface the battery is on or in. Actually hot weather is more determental than cold weather.

 

http://www.homepower.com/articles/solar-electricity/equipment-products/ask-experts-batteries-concrete

[WIGuide]

I always bring mine in and store them in the basement. Maybe it's unnecessary precaution but I'd rather have my batteries last. Also, being that we are in the far north, out boats our in storage longer than those who live farther south and we also deal with more extreme cold temps. Last year we had an entire month that the temp did not get above 0 degrees with many mornings being in the -25 to -35 degree range. Best thing you could do is to bring it in and store it in the basement. Put it on the charger periodically and you'll for sure be good to go in the spring. 

 

There have been a few references to an article here and the last line is this  "At the end of the day, a good rule is that batteries like the same temperatures that humans do, between 60 degF and 80 degF."  I'm willing to follow that rule

[BaitMonkey1984]

Just make sure to hit the batteries with a trickle charge every few weeks and they should be fine, it has worked for me for years. I had someone move one of my batteries onto a concrete floor, and when I discovered it weeks later, the discharge rate was not affected at all. I think it held true in the past, however if you have a way to avoid the batteries sitting on a bare concrete floor, do it. I'd rather spend my money on crank baits than three new batteries for the boat. 

[desmobob]

I use "battery maintainers" for my stored batteries.  They're cheap.  They put just the tiniest bit of current in to keep the chemistry active and prevent sulfating, from what I understand.  You have to charge them on a normal charger first before storing them on the maintainer.

 

I know a guy who keeps a lot of batteries for various toys, etc, in storage for the winter.  He has a bunch of cheap wall-wart trickle chargers hooked to a power strip that's plugged into an appliance timer.  It comes on for half an hour every day to keep the batteries active and charged.

 

 

 

Tight lines,

Bob