[wdfifteen]

"A fully charged battery at 12.7 volts will freeze at -70°F. A half-charged battery (12.0 volts) can start freezing at 5°F and a fully discharged car battery (11.5-volts) will freeze at 32°F."

I have 6 dead 8 volt golf cart batteries and a dead 6 volt battery for my Speedster. None of them will charge up to their full voltage. The 6 volt tops out at 5 volts after a week on a 1.5 amp charger.
They are all old and all need to be replaced.
I don't need the cart and won't be operating the Speedster for at least 6 months, so I don't want to go out and buy $1000 worth of new batteries just to let them sit.
But it gets cold here. Five degrees isn't out of the question, and I don't have a good place to keep them warm. I'm afraid they'll freeze and break and spill acid all over the place even if I keep them on maintainers.
I'm sure folks who handle batteries have encountered this.
I've thought of totally discharging the batteries and dumping the liquid out. What would be the acid content of a battery at 0 volts?
Any suggestions?