LiFePo4 has a very very low self discharge rate
If you charged them and two or three months later pull the tractor out to
remove snow. No charging would be needed to start your work.
After your work is done it is highly likely your cells would
have warmed up enough to charge. You would not want to wait as they would
cool down and then you would have to warm them up.
Here is some interesting information on cold weather performance. Note
the cells are in a bucket of ice cooled to 0 degrees. Even trying to keep the
temperature as low as possible the cell warmed up to 25 degrees under load.
I have a Fluke and it is a very useful tool. Great for bench testing
batteries temps and an endless other things.
Don Blazer
"1. Temperature. Implied in the CALB graph is a steady -20C or -4F. We
cold soaked our cells to 0F, but during the test, held the cell in ice in a
cooler. The temperature rose over the test for both cells from 0 to about 25.5
degrees F."
In a message dated 8/18/2013 9:47:46 A.M. Pacific Daylight Time,
kim coveside net writes:
I
think cold weather charging should be talked about in this
discussion. It is my understanding that LiFePO4 can be damaged if
they
are charged below 32 F. An electrak in an unheated garage
should
probably have a battery heater of some sort if it is going
to be used
for snow removal. If it is recharged right after use
the cells may be
warm enough to not do damage. It is something to
consider.
Kimball