Does not exactly answer your question but full of FACT.
COLD WEATHER OPERATION
Temperature is a vital factor in the operation and life of a storage battery. Chemical
reactions take place more rapidly with heat than with cold. For this reason, a battery will
give much better performance in temperate or tropical climates than in cold climates.
On the other hand, the battery will deteriorate faster in warm climates. In some cases, a
lower specific gravity electrolyte is specified for warm climate operation in order to add
to the life of the battery because chemical reactions are more rapid in warmer climates.
In cold climates, the state of charge in a storage battery should be kept at a maximum.
A fully charged battery will not freeze even under the most severe weather conditions,
but a discharged battery will freeze very easily. When adding water to a battery in
extremely cold weather, the battery must be charged at once. If this is not done, the
water will not mix with the acid and will freeze.
The following table gives the freezing points of electrolyte for various states of charge.
These are the approximate points at which ice crystals start to form. The electrolyte
does not freeze solid until a lower temperature is reached. Solid freezing of electrolyte
in a discharged battery will damage the plates and may rupture the container.
Specific Gravity / Freezing Point
SG Deg C (minus)
1.300 - 70
1.275 - 62
1.250 - 52
1.225 - 37
1.200 - 26
1.175 - 20