Lead Acid Battery Winter Storage

[Selkirk]

My trailer is equipped with the factory-supplied Victron solar controller, two roof-mounted solar panels, and two 6V lead acid batteries.

It will spend the winter at an uncovered storage site.....from early Oct - late April/early May. Snow and sub-freezing temps are expected. However, the area is prone to reasonably frequent warm spells (chinooks) through-out the winter season, so I don't expect the trailer will be snow-covered 100% of the time.

I understand that LA batteries don't carry the same risk of cold weather damage in low temperatures as Lithium, provided that the acid levels are properly maintained and the battery is initially stored with a full charge.

I suspect the optimal procedure would be to disable the solar controller (which I think can be done via the Victron app), fully remove the batteries, and store them at home connected to a battery maintainer.

However, how risky would it be to just keep the batteries in place over winter with the trailer's main disconnect switch open (which still leaves the solar controller connected)...and rely on the solar panels to occasionally charge the batteries whenever they are not covered by snow? The storage facility is close enough to work that it would not be that big of an issue to occasionally stop by and clear off panels....if need be.

Thoughts?

[SageRpod]

Originally Posted by Selkirk

However, how risky would it be to just keep the batteries in place over winter with the trailer's main disconnect switch open (which still leaves the solar controller connected)...and rely on the solar panels to occasionally charge the batteries whenever they are not covered by snow? The storage facility is close enough to work that it would not be that big of an issue to occasionally stop by and clear off panels....if need be.

Thoughts?

Won't be risky at all with the plan you proposed. I did this very same thing with our Rpod except with a 130watt portable solar panel chained to the rear bumper and facing a few degrees off true south. The LA batteries were always fully charged and it sure beat lifting them in and out whenever we wanted to head south for winter camping.

Just make sure you are able to lock your batteries to the trailer.

[Selkirk]

Originally Posted by SageRpod

Won't be risky at all with the plan you proposed. I did this very same thing with our Rpod except with a 130watt portable solar panel chained to the rear bumper and facing a few degrees off true south. The LA batteries were always fully charged and it sure beat lifting them in and out whenever we wanted to head south for winter camping.

Just make sure you are able to lock your batteries to the trailer.

Thanks for the feedback. I really did not want to lug those batteries around if it is reasonable to rely on the solar set-up to maintain them over winter.

ETI now locates the batteries inside the 19, under the dinette bench....so there is little risk of theft.

[HABBERDABBER]

The above poster with the R-pod is in the Southwestern USA. Much, much different Winter conditions between your location and his.

A buddy had an off-grid cottage, solar powered. He had a composting toilet that had a small 12V fan to exhaust odors. An unusually snowy period, with a record long period of cloudy weather occurred. In the several weeks of snow covered solar panels, no sunshine and low but continuous draw from the fan, his batteries went empty. And then a sub-zero cold snap came. It froze his batteries and then they were ruined. Some thou$sand$ of batteries were KAPUT!

Lead acid batteries can freeze. If they are deeply discharged, they freeze at higher levels of temperature.Can a flooded battery freeze?

See here: https://modernsurvivalblog.com/alter...g-temperature/

The only way that a battery can freeze is if it is left in a state of partial or complete discharge. As the state of charge in a battery decreases, the electrolyte becomes more like water and the freezing temperature increases. The freezing temperature of the electrolyte in a fully charged battery is -92º F (-69º C). At a 40% state of charge, electrolyte will freeze if the temperature reaches approximately 16º F (-9º C).

More info here:
https://www.batteryskills.com/can-battery-acid-freeze/

I pull my batteries every winter, store them in an insulated but unheated attached garage. It rarely gets to freezing in there and I'll plop a trickle charger on them every couple of weeks. That has worked very well for me.

Mine are in the front storage box, they're heavy, but with help can be removed. I also remove them solo without a major problem.

Having fun is a lot of work. An ounce of prevention......you know the rest.