Safe battery procedure for MN Winter storage?

[fishbisquit]

Hey Everyone,
I know there are a lot of threads about this already. I've been reading most of them the last 2 days. But I'm still a bit confused as there seems to be conflicting info. I'm wondering about the best battery procedure for cold weather storage? We live in MN, so Winters get cold. Our 2018 AS sport has been in the driveway, plugged into shore power for the last 2 months. I was planning on keeping it this way at least another 3 months. I was told and have read that people have been doing this for years with no problems and their batteries are fine. I've just recently been reading that that long term connection to shore power can hurt the batteries. There was one post here where someone mentions his battery exploded. Now I'm really freaked out and am confused about the best procedure. I just checked the batteries and they seem fine. Reading was 12.8 after disconnecting shore power. Any helpful comments would be greatly appreciated! Below are few of my questions.

Can I leave connect to shore power all Winter?

Could I leave batteries connected to trailer and plug into shore power once a week for a day? Will batteries discharge and freeze in less then a week?

If I decide to disconnect batteries and bring inside, is it safe after being connected for 2 months? (explosion post really scared me!)

Can I leave detached batteries in unheated garage connected to a battery tender?

[rmkrum]

Seriously, ANY of these methods will work. I'm also relatively sure the 'exploding battery' one was a fluke...with reasonable care, flooded wet-cell batteries don't spontaneously explode in the sense of a violent, destructive explosion. They are more likely to bulge and crack, and spill their contents--which is a mess, true.

My personal choice, however, would be to put the batteries in a warm space, like a semi-heated basement, on a battery tender so you can easily check water levels and replenish them over the winter if needed. Put the batteries on a solid surface, in a convenient area for checking them, and not subject to falling or flooding...or curious children.

[fishbisquit]

I should have also stated that I know the long time "right" way to do this is to disconnect batteries and bring inside. However I am hoping to avoid this for a few reasons. Since I have easy access to shore power I was hoping for a convenient solution.

The 2 batteries I have are Interstate Deep Cycle Marine group 24. I just called up Interstate to find out what they recommend for cold weather storage. They said that if there is no draw on the batteries they should be fine for 1.5-2 months outside. They suggested checking the voltage once a month and if it gets to 12.5 to plug them in for a few hours to charge up and then unplug shore power again. This sounds like my perfect solution unless someone sees an issue I do not? Also should I pull the fuse to the CO2 monitor?

[markdoane]

Your best bet is to move it to your unheated garage and leave it on a battery tender.

The only reason is if you wake up some morning and your car battery is dead, you have a charged up spare sitting in the garage ready to use to jump start your car.

Or leave it in the trailer and just Uber to work.

[rmkrum]

OK, now I understand your situation better. Since you have shore power available, you are in a better situation than I am. I depend on solar power, and store the Airstream outside, winterized, here in the Southern California high desert. We don't get quite as cold as your area...but I know what it's like--I lived many years in Chicago...

I'd leave the batteries installed, totally disconnected from the trailer loads, and use a battery tender to keep them charged. That way, if you forget to check, the battery tender won't be trying to power the parasitic loads in the trailer, and will keep the batteries charged.

I'd consider installing a real manual battery disconnect switch at the batteries to totally cut off the loads in the trailer in the winter. This avoids fiddling with the cables, and trying to remember how to hook them back up. There are several threads about how to install and properly wire a manual disconnect switch. I use one from Blue Sea Systems, but there are other mechanical positive disconnect switches available.

Hook the battery tender directly to the battery posts using ring terminals, and use with the fuse assembly that comes with it to protect the wires against accidental shorts.

[ROBERT CROSS]

What I did...started out removing and storing inside, evolved to checking the batteries regularly and plug in when needed...

Others have noted some of the upgrades that will present themselves down the road, one of our first was installing better batteries and converter. (IOTA IQ4 55a & 2 AGM Lifeline)

Sweet Streams

Bob
🇺🇸

BTW...gets cold in Bflo too..😂

[Bill M.]

One way is to put the trailer on a timer so that it has power for one to two hours per day.

[gordyfj49]

Originally Posted by rmkrum

Seriously, ANY of these methods will work. I'm also relatively sure the 'exploding battery' one was a fluke...with reasonable care, flooded wet-cell batteries don't spontaneously explode in the sense of a violent, destructive explosion. They are more likely to bulge and crack, and spill their contents--which is a mess, true.

My personal choice, however, would be to put the batteries in a warm space, like a semi-heated basement, on a battery tender so you can easily check water levels and replenish them over the winter if needed. Put the batteries on a solid surface, in a convenient area for checking them, and not subject to falling or flooding...or curious children.

What he said!

[75Bob]

I have a dedicated battery charge area in the garage. 2 Airstream batteries 1 corvette battery 2 motorcycle and 2 four wheeler batteries all on a wooden flat surface, each connected to their own trickle charger.When I'm ready to go so are they.

[fishbisquit]

Originally Posted by Bill M.

One way is to put the trailer on a timer so that it has power for one to two hours per day.

This is a brilliant idea! So simple, I love it. Curious how you came up wiht 1-2 hours per day? Thanks again, love these boards!

[Wetfeet]

My 2015 FC20 sits outside all winter in Wyoming hooked up to shore power, and the batteries do just fine. I doubt it gets any colder in MN. Apparently some older Airstreams came with chargers that don’t automatically throttle back to trickle, and you will read lots of threads claiming what I do will “boil the batteries”.

[waninae39]

i bring my LiOn battery inside as it does not like 0C or below

i put my old Lead Acid battery inside the As in the winter to run any system i monitor

[jcanavera]

Since my trailer always has a draw of power (even though the master disconnect is switched off), I cannot leave the batteries in the trailer without providing some sort of charge to them. Constantly leaving the trailer plugged in will not work without causing excessive evaporation of the battery fluids.

I now pull the batteries when I winterize. The batteries are in my garage on a trickle charger. Once spring comes I reinstall the batteries prior to bringing the trailer home to dewinterize. In the summer I don't charge the batteries since a once a month travel cycle keeps the batteries sufficiently charged. However I do always turn the master disconnect off when I park the trailer between trips. Leaving it on, even with all appliances turned off will kill the batteries within 4 weeks or so.

I did measure the draw on the batteries and found with master disconnect on, the draw was .1 of an amp. With the disconnect off, the draw is .01 amp. Dealer told me that all the electronics in the trailer while turned off still draw power with the master disconnect on. When it is switched off, the only draw is from the propane detector.

Jack

[ROBERT CROSS]

I shut the power down completely. 👍 Leave the batteries in the AS and monitor from inside the house with Victron dongle.

Bob
🇺🇸

[68 Overlander]

With a 4 stage converter that has a desufation cycle, I have stored outside in Boise, ID for 11 years and the batteries are finally starting to show signs of capacity loss. It's my hunting/fishing camper that doesn't get used much since I no longer live there. They are AGM and my next batteries will be Fullriver 220-6 for the 7 year warranty just in case I don't get lucky again.
There are millions of vehicles that spend the winter outside in the northern states and do fine but if you want to pull them for piece of mind, by all means go for it.

[ROBERT CROSS]

Originally Posted by waninae39

i bring my LiOn battery inside as it does not like 0C or below

i put my old Lead Acid battery inside the As in the winter to run any system i monitor

As I understand the BB specs...the BMS won't charge below 25*f, but being cold won't damage them.
Ours are in the AS @100%/13.45v, SFSG...If they get to 35% I'll plug in at 32*.

Bob
🇺🇸

[Vitaver]

Unfortunately I left my coach at the dealer for some cosmetic repairs (hail damage) for 3 months and they did not connect to shore power. My AGMs went flat and never recovered. I am waiting for Spring to buy new ones, Interstate has a special lower price for Airstream owners. Still, not ideal...

[ROBERT CROSS]

Originally Posted by Vitaver

Unfortunately I left my coach at the dealer for some cosmetic repairs (hail damage) for 3 months and they did not connect to shore power. My AGMs went flat and never recovered. I am waiting for Spring to buy new ones, Interstate has a special lower price for Airstream owners. Still, not ideal...

Must have been quite a parasitic draw on them.
Before getting lithium our Lifeline AGM's could go for an entire Winter, in the AS, with a full charge in November.

Bob
🇺🇸

[mefly2]

Originally Posted by Bill M.

One way is to put the trailer on a timer so that it has power for one to two hours per day.

That's what we do ... cheaper than the multi-stage charger at this point ...

[Farmer Dan]

I did the same as Bill M. and mefly2 when I stored my trailer in an unheated shed. One thing I didn't see mentioned in these posts was the water level in the batteries. If this is up to the specified level at the beginning of the storage season and with the timer running relatively short periods, I wouldn't think more water would be needed - but a check on it a couple times may be a good idea.


Dan