LiFePO4 Sub-Zero Temperature Charging Protection
Core Question: What happens if a Lithium Iron Phosphate (LiFePO4) solar battery is charged below 0°C (32°F)?
Executive Technical Summary
Charging a LiFePO4 battery below freezing causes irreversible metallic lithium plating on the graphite anode, permanently destroying capacity and creating internal micro-short circuit fire risks.
Detailed First-Principles Explanation
At sub-zero temperatures, the diffusion rate of lithium ions through the electrolyte slows dramatically. When charging current is applied, ions cannot intercalate into the anode structure fast enough and instead deposit as solid metallic lithium needles (dendrites) that can pierce the separator.
Discharging below 0°C is safe down to -20°C, but charging is strictly prohibited. Always choose home batteries with integrated internal heating pads for unheated garage or outdoor installs.