When sourcing LiFePO4 rack batteries, you must prioritize Cycle Life, typically looking for 6,000+ cycles at 80% Depth of Discharge (DoD). Ensure the Battery Management System (BMS) supports features like over-charge, over-discharge, and thermal protection. Additionally, verify the nominal voltage (usually 48V or 51.2V) and the energy density (kWh) to ensure it meets your load requirements. For rack-mounted systems, standard 19-inch compatibility is essential for seamless integration into server racks.