Leaving batteries in the cold

[Willowflowage]

Thoughts on leaving 2-6v golf batteries out for a cold northern winter?
I've got them hooked to a 100w solar panel and controller while the trailers parked till spring. Last night minus 21. It had a 12.4v reading in the morning. I keep snow off it and monitor it daily and can easily plug it into shore power if I need to, it climbs up to 14,+v during the day charging. And falls to 12.6 at sunset.
Any big issues here?

 

[John From Detroit]

You should be good to around -40 F/C with the batteries fully charged. and they are.

 

[Ex-Calif]

I think you are fine but I always put my unattended batteries in the garage on a battery tender.

 

[Mark_K5LXP]

A fully charged lead acid battery won't freeze until some thing like -70F so from that perspective there's no issue. Your reported numbers though indicate that your batteries are either not fully charging or something is drawing them down. The open circuit voltage for a battery this cold will be 13V, not 12.4. Likely still not a freeze risk but if there is a draw there and either your solar goes away (clouds, snow) or the load increases that state of charge may get below the freezing point. For -20F that would be about 60% charged and at that temperature 60% open circuit voltage is very close to 12.4V. If outdoor storage is the plan I'd figure out a way to ensure my batteries stayed at 100%. Disconnecting them from the house loads would be the way that works for sure as is ExCalif's method.

Mark B.
Albuquerque, NM

 

[Kirk]

The open circuit voltage for a battery this cold will be 13V, not 12.4.

Not true. The nominal voltage of lead acid batteries is 2 volts per cell, however when measuring the open circuit voltage, the OCV of a charged and rested battery should be 2.1V/cell. My source is the Trojan Battery Company site.

 

[decaturbob]

Thoughts on leaving 2-6v golf batteries out for a cold northern winter?
I've got them hooked to a 100w solar panel and controller while the trailers parked till spring. Last night minus 21. It had a 12.4v reading in the morning. I keep snow off it and monitor it daily and can easily plug it into shore power if I need to, it climbs up to 14,+v during the day charging. And falls to 12.6 at sunset.
Any big issues here?

- the key thing? You are keeping the batteries charged. BUT YOU NEED to keep on eye on the fluid level unless you got cell caps that capture the vapor and retains it in the cell.