LEAD
/ ACID battery NFO:
This table will show you , when the battery freezes. ( -95
degree's F is very cold ) Keep it charged and it will not freeze.
1: The state of charge [SOC] on the battery at room
temperature
(20°C); [ meaning you can measure the voltage and know
the charge]
2.: The point the battery will freeze. ( good to know if you live up
north )
Discharged
lead-acid batteries exposed to cold temperatures are subject to plate
damage
due to freezing of the electrolyte.
To prevent freezing damage, maintain
each cell’s specific gravity at 1.275, or for sealed lead-acid
batteries
check “open” circuit voltage.
. Lead-acid battery electrolyte freezing points.
Some Makers of batteries, have different voltages for fully
charged, see their web site for your battery performance.
Specific
Freeze Point
State of
Charge at 70 deg F. ( a very crude chart see this for more accuracy on SOC)
Gravity
|
C.
|
F.
|
SOC
|
12-volt
|
|
1.300
|
-70
|
-95
|
100%
|
12.9
|
|
1.275
|
-62
|
-80
|
75%
|
12.7
|
|
1.250
|
-52
|
-62
|
50%
|
12.4
|
|
1.225
|
-37
|
-35
|
25%
|
12.0
|
|
1.200
|
-26
|
-17
|
|
|
|
1.175
|
-20
|
-4
|
|
|
|
1.150
|
-15
|
+5
|
|
|
|
1.125
|
-10
|
+13
|
|
|
|
1.100
|
-8
|
+18
|
|
|
|
As one can see , one would have to be in an extremely cold climate to
freeze a fully charged battery.
-95 degrees Fahrenheit , that is darn cold.
This number comes from the FAA tables , see PDF
document here.
So , if you don't live in , lets say:
Prospect Creek Camp in the Endicott Mountains of Northern Alaska (
lowest in US -80f)
AND you keep your battery above 75% charged, your battery won't split
open. ( wind chill effect , not withstanding).