Troubleshooting Guide - LiFePO4 Battery Issues

DIAGNOSTIC PROTOCOL

Troubleshooting
Guide.

Common issues, diagnostic procedures, and solutions for Sentorise LiFePO4 batteries. Follow these steps to identify and resolve system problems.

Quick Diagnostic Checklist

Before troubleshooting, verify these basics:

  • All connections are tight and corrosion-free
  • Battery voltage is within normal range (12.8-13.6V for 12V models)
  • Charger is set to LiFePO4 mode (14.2-14.6V)
  • No visible damage to battery case or terminals
  • Ambient temperature is within operating range (-20°C to 60°C)

⚡ Charging Issues

❌ Battery Won't Charge

Battery voltage not increasing when charger is connected.

Possible Causes & Solutions:

  1. Temperature too low (<0°C): BMS blocks charging below freezing. Move battery to warmer location or use battery heater.
  2. Charger voltage too high: BMS protection triggered. Verify charger is set to 14.2-14.6V (not 14.8V+).
  3. Loose connections: Check and tighten all cable connections. Verify continuity with multimeter.
  4. BMS protection mode: Disconnect battery for 30 seconds to reset BMS, then reconnect.
❌ Charging Stops Prematurely

Charger stops before battery reaches full capacity.

Possible Causes & Solutions:

  1. Charger in float mode: LiFePO4 batteries don't need float charging. Disable float or set to 13.6V maximum.
  2. Cell imbalance: BMS may stop charging to balance cells. Allow 2-4 hours for balancing, then resume.
  3. Charger current too low: Verify charger can deliver at least 0.2C (20A for 100Ah battery).
❌ Slow Charging Speed

Battery takes much longer than expected to charge.

Possible Causes & Solutions:

  1. Undersized charger: Verify charger amperage. Sentorise batteries support 1C charging (100A for 100Ah).
  2. Voltage drop in cables: Use appropriate cable gauge. 4 AWG minimum for 100A loads.
  3. Cold temperature: Charging slows below 10°C. This is normal BMS behavior for cell protection.

🔋 Discharge Issues

❌ Battery Voltage Drops Quickly Under Load

Voltage drops significantly when appliances are turned on.

Possible Causes & Solutions:

  1. Exceeding continuous current rating: Verify load doesn't exceed 100A continuous (for 100Ah models). Reduce load or add second battery in parallel.
  2. Poor cable connections: Voltage drop indicates resistance. Check all connections and cable gauge.
  3. Battery at low state of charge: LiFePO4 voltage drops sharply below 20% SOC. Recharge battery.
  4. Cold temperature: Discharge capacity reduces below 0°C. This is normal behavior.

⚠️ WARNING: If voltage drops below 10V under load, BMS will disconnect to protect cells. This is not a defect.

❌ Battery Shuts Off Unexpectedly

Power cuts out suddenly during use.

Possible Causes & Solutions:

  1. Over-current protection: Load exceeds 200A peak limit. BMS disconnects to protect cells. Reduce load.
  2. Low voltage cutoff: Battery discharged below 10V. BMS protection activated. Recharge immediately.
  3. Loose connection: Vibration causing intermittent contact. Tighten all terminals to 10-12 Nm.
  4. Temperature protection: Battery too hot (>60°C) or too cold (<-20°C). Allow to return to normal range.
❌ Reduced Runtime

Battery doesn't last as long as expected between charges.

Possible Causes & Solutions:

  1. Battery not fully charged: Verify charger reaches 14.4V and holds for 1-2 hours.
  2. Parasitic loads: Check for devices drawing power when system is "off". Use multimeter to measure standby current.
  3. Increased power consumption: Verify actual load matches expectations. Use energy monitor to measure usage.
  4. Cell imbalance: Perform full charge cycle (0-100%) to allow BMS to balance cells.

⚙️ System & BMS Issues

❌ Battery Monitor Shows Incorrect State of Charge

SOC reading doesn't match actual battery capacity.

Possible Causes & Solutions:

  1. Monitor not calibrated for LiFePO4: Set voltage parameters: 100% = 13.6V, 50% = 13.2V, 0% = 10.0V.
  2. Shunt not properly connected: Verify all loads and chargers pass through shunt.
  3. Monitor needs synchronization: Perform full charge cycle to 14.4V to sync monitor.

💡 TIP: LiFePO4 voltage-based SOC is less accurate than lead-acid. Use shunt-based monitors for best results.

❌ Battery Feels Warm During Charging

Battery case temperature increases noticeably.

Possible Causes & Solutions:

  1. Normal operation: Slight warmth (up to 40°C) during fast charging is normal. No action needed.
  2. High ambient temperature: Ensure adequate ventilation. Minimum 50mm clearance on all sides.
  3. Excessive charge current: Reduce charge rate to 0.5C (50A for 100Ah) if temperature exceeds 45°C.
  4. Poor ventilation: Remove obstructions around battery. Install ventilation fan if needed.

⚠️ CRITICAL: If battery exceeds 60°C, disconnect immediately and contact support. Do not continue use.

When to Contact Support

Contact Sentorise technical support immediately if:

  • Battery case is swollen, cracked, or leaking
  • Unusual odors or smoke from battery
  • Battery voltage below 8V or above 16V
  • BMS repeatedly disconnects without obvious cause
  • Capacity loss exceeds 20% within warranty period
  • Physical damage from impact or water ingress

Still Need Help?

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