If we look at the lithium battery's voltage chart, we should keep it between 12. LiFePO4 cells have a nominal voltage of 3. Factor in 10-15% efficiency losses and plan for 20% capacity degradation over 10 years when sizing your system. 8V (4-cell) pack powers an RV's LED. . Therefore, it is recommended to store LiFePO4 batteries at a state of charge between 40% and 60% and at a cool temperature, ideally between 32°F and 77°F or 0°C and 25°C. Should you keep LiFePO4 batteries fully. . A 36 volt or 72 volt system might be the simplest to use the battery packs as they are, but finding complimentary equipment seems to be harder.