COLD's impact on LiFePO4 (Mottcell)

My Enginer Kit is older, but it is also quite a bit colder. Is there a significant difference in usable energy at 40 degrees vs. 80 degrees? I would expect so but would like confirmation.

(Similar profile as Pb? Very familiar with the various levels of cold's effects on Lead-Acid Batteries.)

Thanks!

 

Thanks. It is now 30 degrees My car is in the garage too, so perhaps a max of 35 degrees.

I have a voltmeter inside the car for the 50v pack. When it was much warmer, 65-70-80 degrees, it would take perhaps 15 minutes of use before the volt meter would dip below 50v. Now it immediately drops to 49.x MUCH sooner (with a top-off). Could the the cold and older batteries. And my overall range has dropped by nearly 10 miles.

I am considering using an electric blanket, as much as an experiment. I need to move my 2KW of batteries into the spare tire well, and I knew I needed to do something to pad the cells. Thinking of using household insulation on the bottom and sides and an electric blanket to wrap the cells. I have been monitoring the temp with a thermometer and a Kill-O-Watt meeter to see the current draw. On just about the lowest setting, it is easy to maintain 80 degrees inside. Since heat rises, the Enginer box will have to get some of the heat too.