Battery Over Voltage

What does F75 mean?

This Manual Fault indicates that the DC bus voltage has exceeded the BMS charge reference voltage. This suggests that the battery pack voltage is too high, which could lead to overcharging and damage if not corrected.

• Charging source (e.g., solar array, grid charger) providing an unregulated or excessively high voltage output.
• Malfunction in the inverter's charging regulation circuit, failing to limit the charging voltage as battery voltage increases.
• Faulty Battery Management System (BMS) voltage sensor providing erroneous high readings, triggering a false overvoltage fault.
• Internal short circuit or overcharging of a single cell within the Li-ion battery pack, leading to overall pack overvoltage.
• Incorrectly configured maximum charge voltage limit in the inverter or BMS settings (e.g., Parameter B1-11 set too low).

Click steps to track your progress.

1. 1

   1. Measure the DC bus voltage directly at the inverter's battery terminals using a calibrated DC voltmeter and compare it to the BMS's reported voltage.

2. 2

   2. Access the Battery Management System (BMS) diagnostics interface to verify the reported battery voltage and individual cell voltages, looking for discrepancies.

3. 3

   3. Disconnect all charging sources (e.g., PV array, AC input) and observe if the battery voltage stabilizes within its normal operating range.

4. 4

   4. Review the inverter's configuration for the maximum battery charge voltage (e.g., Parameter B1-11) and ensure it matches the battery manufacturer's specifications.

5. 5

   5. Verify the voltage regulation settings of any external charging controllers (e.g., MPPT controllers) to ensure they are properly limiting output voltage.