Winter solar battery charging when you can't add water?

"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 -92F. At a 40% state of charge, electrolyte will freeze if the temperature reaches approximately 16F." I'd take them with me.

Source of information "Trojan Battery Company"
Trojan Battery Company Website

smkettner wrote:
I would leave them on solar. No water should be needed for at least six months.

I conditionally agree. If the OP is referring to lower winter snow area (he lists Meza, AZ in his profile) then leave the batteries connected to solar.

Second condition is that ALL RV loads/wiring are fully disconnected from the batteries.

In theory you can arrange it right to leave them on solar and all will be well. OR for no nail- biting for seven months, you can take them home and know they are all right.

Leave on solar, set float voltage on controller, save your back for other tasks.

Hi,

I would fill them with water and leave them on the solar charger. What charge controller do you have?

I would leave them on solar. No water should be needed for at least six months.

If your charger is a smart mode charger it probably will never heat the batteries up enough to boil fluids out. I lost one battery due to the fluids being boiled out and then changed over to smart mode charging. I still check my batteries every couple of weeks but never see them low on fluids any more.

I probably would just just remove the batteries in your case since you are not around to check on them for that long of a time frame...

A fully charged battery will not freeze but being disconnected for that long of time the charge would probably start dropping off on you unless you had some sort of solar trickle charge feeding them.

Batteries are too expensive to just abandon for that long of time without hands on maintenance of some sort.

Roy Ken

Take them with you.

I would take the batteries home and care for them. Mainly because your solar will probley be covered in snow often. Let's see what others say?