Is it ok to winter-store 2-6 volt batteries in an unheated garage?

[jwalt313]

Is it ok to keep 2-6 volt batteries on a Battery Tender in an unheated garage over the winter in Pennsylvania? My husband always put them in our basement but after 2 knee replacements, he struggles to carry them downstairs. Our 21FBRS is stored on a storage lot without electricity. Will it harm the batteries to store them with the Battery Tender in a cold garage over the winter?

[BehindBars]

Originally Posted by jwalt313

Is it ok to keep 2-6 volt batteries on a Battery Tender in an unheated garage over the winter in Pennsylvania? My husband always put them in our basement but after 2 knee replacements, he struggles to carry them downstairs. Our 21FBRS is stored on a storage lot without electricity. Will it harm the batteries to store them with the Battery Tender in a cold garage over the winter?

It is preferable to store the batteries in a cool unheated area, as long as they are charged. Batteries stored cold will have less self discharge and will have a longer life. So, yes, it will be better for both your husband knees and for the batteries to store the batteries in the cold garage.

[Herk7769]

How are you planning on using the Battery Tender if there is no electricity?

Don't for get to REMOVE all wires from the negative terminal of the batteries.

[BehindBars]

Originally Posted by Herk7769

How are you planning on using the Battery Tender if there is no electricity?

Don't for get to REMOVE all wires from the negative terminal of the batteries.

From the first post, I read that the RV is stored on a storage lot without electricity. The batteries will be in a garage that has electricity, so there is power for the battery charger.

[Herk7769]

thanks I obviously missed that.

[SailorSam20500]

I've posted this before:
Here's a link that has some specifics on cold weather battery status based on tests by the US Army Corp of Engineers.
The document states "Batteries should be stored in a cold place, say, about -15C (+5F), although when charged to a specific gravity of 1.280 or greater, they can be stored at -1C (+30.2F) indefinitely without deteriorating."

https://apps.dtic.mil/dtic/tr/fulltext/u2/a239115.pdf

If they are fully charged and stored in a cold area, there is no need for a tender.
There is no need to store them sitting on a board rather than concrete. Using a board was needed years ago when battery bodies were made from other products. Modern plastic bodied batteries are not affected by sitting on concrete or any other surface.
Finally, if they are fully charged at this point, there is no reason to remove them from your RV, unless you are worried about someone stealing them. Just disconnect them from ALL loads.

[PenJoe]

I, too, have two knee replacements going past 15 years now. I had simultaneous (bilateral) total knee replacements, followed by extensive therapies. Then I started to put them to the test of doing strenuous activities including hand mixing and laying concrete. Sometimes on my knees. DW ratted on me at my next check up. Rather than side with DW, the doctor said, "Use them." I have. Though it is difficult to get up off the ground, I can. It is difficult to climb stairs. I do, always hanging onto a rail. I am not supposed to cross my legs. I do. I have even carried the batteries up and down the stairs, leaning against the rail to maintain balance. But the one thing I have noticed is that it is sometimes difficult to keep balance, especially on a quick twist. Hubby should do just fine.

Yes, I store batteries in our garage. An insulated garage attached to the house will rarely go below freezing even in sub zero temps. An attached garage without insulation will get a few degrees colder than insulated. Similar if it is an unattached garage.

We store our truck in the winter and have a battery tender on it. We remove the negative cable from the terminal post. In the spring, the battery is fully charged. Other batteries stored in the garage are first brought up to a full charge for storage, then again before first use the following season. The only battery we lost over the winter was a riding mower battery and they normally have a shorter life span.

[Sarahcat]

Another plus is that batteries on float charge, i.e., fully charged, have a freeze point around -50°F.

[Campah]

Originally Posted by jwalt313

Is it ok to keep 2-6 volt batteries on a Battery Tender in an unheated garage over the winter in Pennsylvania? My husband always put them in our basement but after 2 knee replacements, he struggles to carry them downstairs. Our 21FBRS is stored on a storage lot without electricity. Will it harm the batteries to store them with the Battery Tender in a cold garage over the winter?

No issue. I do store my two 6 volt GC in an unheated basement on a battery tender but as long as you keep them charged they won’t freeze. Just like your car.

But note, these need to be topped off with distilled water from time to time. (BTW, we have the Rockwood 2109s which is the sister to your 21FBRs).

[5picker]

Originally Posted by Sarahcat

Another plus is that batteries on float charge, i.e., fully charged, have a freeze point around 50°F.9

Did you forget the - sign? (-50°F)
If fully charged, properly disconnected and NOT on a tender, they won't freeze above -50°F.

[kluza2786]

Also make sure that they aren't sitting on the bare concrete - i.e. put some wood underneath them.

[camaraderie]

For the record... a fully charged wet cell battery will not freeze if left outside anywhere in the USA or Canada. A 40% discharged battery is still good to -20 degrees.

[5picker]

Originally Posted by kluza2786

Also make sure that they aren't sitting on the bare concrete - i.e. put some wood underneath them.

Not true. That's become an old wives tale.
Modern battery case material (last 50 years) is not affected by sitting directly on concrete.

[Sarahcat]

e

Originally Posted by 5picker

Did you forget the - sign? (-50°F)
If fully charged, properly disconnected and NOT on a tender, they won't freeze above -50°F.

Yes, I typoed the temperature and I've corrected the original post: -50ºF. I know that a fully charged battery, on float charge or not, will maintain the lower freeze point as long as it is not discharged significantly. The OP asked specifically about unheated garages AND a battery tender (float charge maintainer). Our garage is insulated and semi-heated and we still use cheap battery tenders on our batteries once we have shut down for the season. I'm pretty well schooled on battery chemistries and given the cost, we prefer to maintain the house batteries at their peak for our Spring startup. It's unlikely that leaving a battery in the TT all winter would do much to discharge them, but it's easy to remove them and we have a small roller dolly (so we can easily move them around) and two dirt cheap battery tenders and we'd rather not have our batteries 'borrowed' by another camper who uses our otherwise secure storage facility, particularly since we're eyeing relatively inexpensive LiPO batteries from Costco.

[PenJoe]

Originally Posted by kluza2786

Also make sure that they aren't sitting on the bare concrete - i.e. put some wood underneath them.

For years I believed this as being the gospel truth and I always stored batteries on wood. That was true with Edison batteries, but not with newer styles.Guess what, I still store batteries on wood! What can I say?

Why Does Storing a Car Battery on a Concrete Floor Drain It?

[BehindBars]

Originally Posted by kluza2786

Also make sure that they aren't sitting on the bare concrete - i.e. put some wood underneath them.

Can you please explain the reason for not storing batteries on concrete? Can you cite a modern source for that recommendation?

Seriously, for modern batteries this advice is nonsense and very, very out of date, unless you are still using batteries made with wood cases.

Or, maybe you posted this as a joke and I missed the humor.

https://www.mcgill.ca/oss/article/ge...tored-concrete

[cariboo camper]

Wow! KLUZA 2786 guess you just got schooled! lol. Too be honest I thought keeping batteries off cement was still relevant. Good to know. I will still keep my batteries on boards, some one may see I do that and get a laugh out of my silliness.

[awellis3]

Originally Posted by 5picker

Not true. That's become an old wives tale.
Modern battery case material (last 50 years) is not affected by sitting directly on concrete.

But it's still a good idea to kick tires, right?

[boondocking]

Originally Posted by awellis3

But it's still a good idea to kick tires, right?

As long as they are no "China Bombs"

[jwalt313]

Thanks everyone. Your knowledge has been so informative and will save my husband from carrying those heavy batteries down the basement stairs.