glazed eyeball alert ... from recent research
translated: as temperature goes down your LiFePO4 battery's internal resistance goes up, reducing amount of amps available to start your engine.
LiFePO4battery performances testing and analyzing for BMS
Dr. Languang Lu, Department of Automotive Engineering,
Tsinghua University, ECG (Engine Control Group) Aug.2011
The maximum ability discharge current (SOF)
① The ability discharge current (the lowest voltage is 2.5V per cell) is strongly connected with temperature. The lower temperature, the lower ability to discharge current because of high resistance under low temperature. The ability current at -20℃ is about 20% of that at room temperature.
② the SOF also concern with SOC, the lower SOC, the lower SOF because of the high resistance. The ability discharge current at 10%SOC is about 40% of that at 90%SOC