LFP Battery Service

1. Visual Inspection
• Cracks, dents, or discoloration on cells, modules, and enclosure.
• Corrosion at terminals and electrical connections.
• Loose connections in bolts, busbars, and fuses.
 • Insulation faults – check for cable wear and proper securing of wires.

2. Electrical Measurements

Resting and Operating Voltage

• A fully charged LFP cell after resting: approx. 3.33 V per cell = 26.6 V (for an 8-cell pack).
 • Minimum voltage: 2.7 V per cell = 21.6 V (for an 8-cell pack).

Capacity Test

• Discharge the battery under controlled conditions (0.5C recommended) and measure the ampere-hours (Ah).
 • Compare with nominal capacity (< 80% capacity → service or replacement).

3. BMS (Battery Management System)

• Verify communication.
• Read BMS data: cell balance, temperatures, State of Charge (SoC), State of Health (SoH), and error logs.
• Ensure cell balancing functions correctly and that no cell exceeds 3.65 V.

• Check log for OV, UV, COC, DOC, SC
 • Check protection limits for:

• Over/under voltage
• Overcurrent

4. Temperature and Environment

• LFP performs best between 10 – 45 °C.
• Charging below 0 °C is not recommended (may cause lithium plating).
• Ensure clean ventilation and unobstructed airflow, especially inside enclosures.
 • Check temperature sensors – faulty readings are a common BMS issue.

5. Safety and Insulation Test

• Measure insulation to chassis (typically > 1 MΩ at 500 V test voltage).
• Check fuses, contactors, and relays.
• Ensure proper grounding and EMC shielding.
 • Verify that the pre-charge circuit operates correctly (to prevent inrush current).

6. Maintenance Intervals

• Every 12 months: Visual inspection, voltage check, cell balance, and BMS functionality.
• Every 24 months: Capacity test and insulation measurement.
 • After 5 years (or 2000–3000 cycles): Full diagnostic and possible re-certification

7. What to Avoid

• No fast charging without approved BMS supervision.
• Do not store fully charged for extended periods – ideal storage level: 40–60% SoC.
• Avoid deep discharge below 2.7 V per cell.
 • Use only LFP-compatible chargers with the correct voltage profile.