Fault

C04

Cell undervoltage.

17 Devices that report this code
C04Cell undervoltage.Fault
Description

Cell undervoltage fault. LED pattern: LED1 OFF, LED2 OFF, LED3 ON, LED4 OFF.

Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf · page 1
C04Cell undervoltage.Faulthigh
Description

Individual cell voltage dropped below the lower limit.

Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:Felicitysolar FLA48200 48V 200Ah 10kWh Lithium Phosphate Battery User Manual.pdf · page 12
C04Cell undervoltage.Critical
Description

Individual cell voltage has fallen below its lower protection threshold.

Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:6peluqppy_66a93554057c8.pdf · page 12
C04C04Fault
Description

Cell undervoltage.

Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:FLA48250-EU_Manual.pdf · page 8
C04Cell undervoltage.Fault
Description

Individual cell undervoltage protection triggered.

Cause

One or more cells dropped below the per-cell lower voltage limit.

Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:felicitysolar FLA48500 LiFePO4 Battery System for Households User Guide.pdf
C04Zell-Unterspannung.Fault
Description

Cell undervoltage. Voltage of a single cell fell below the rated lower protection threshold.

Cause

Cell voltage below protection value during discharge (Zellenspannung unter dem Schutzwert).

Recommended fix

Restart the unit. if the error persists, return to repair centre.

Source:Benutzerhandbuch - Felicity FLS48100SG2.pdf
C04Cell undervoltage.Fault
Description

Individual cell undervoltage protection triggered.

Cause

One or more cells dropped below the per-cell lower voltage limit.

Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:HE-GF-FLA-48500 Manual_20250327_EN.pdf
C04Single cell undervoltage.Fault
Description

Individual-cell under-voltage fault displayed on the LCD BMS fault code / flag screen (section 4.4); one or more cells fell below the lower cell-voltage limit.

Cause

Deep discharge or a weak / aged cell pulling below the under-voltage threshold.

Recommended fix

Restart the unit, if the error persists, contact the repair center.

Source:358-010291-07.pdf · page 8
C04Single cell undervoltage.Fault
Description

An individual cell voltage has dropped below the protection limit.

Cause

One cell voltage below safe lower threshold (cell imbalance or over-discharge).

Recommended fix

Restart the unit; if the error persists, contact the repair center.

Source:Manual-LPBF48200-H.pdf · page 10
C04C04Fault
Recommended fix

Restart the unit, if the error persists, contact the repair center.

Source:Felicitysolar LPBF48350 17.5kWh 48V Solar Battery Pack with BMS User Guide.pdf
C04Cell undervoltage.Fault
Cause

An individual cell voltage fell below the lower protection threshold.

Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:LUX-E-48100LG03-Lithium-Battery-User-Guide.pdf · page 12
C04C04Fault
Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:LUX-E-48200LG03-Lithium-Battery-User-Guide.pdf · page 12
C04C04Fault
Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:LUX-E-48230.250LG03-Lithium-Battery-User-Guide.pdf
C04C04Fault
Description

Cell undervoltage.

Recommended fix

Restart the unit, if the error persists, contact the repair center.

Source:LUX-X-48050LG01-low-voltage-battery-user-guide.pdf · page 17
C04Cell undervoltage.Critical
Description

An individual cell voltage has dropped below its lower protection threshold.

Recommended fix

Restart the unit; if the error persists, contact the repair center.

Source:LUX-X-48100LG01-Litium-Battery-User-Guide.pdf · page 17
C04Cell undervoltage.Critical
Description

An individual cell voltage has dropped below its lower protection threshold.

Recommended fix

Restart the unit, if the error persists, contact the repair center.

Source:358-S010024-03LUX-X-48100LG01-User-manual_compressed.pdf · page 23
C04Cell undervoltage.Fault
Cause

An individual cell voltage fell below the lower protection threshold.

Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:LUX-Y-4828048300LG01-Lithium-Battery-User-Guide.pdf · page 8

Compiled from official FelicityESS user manuals. Always consult your device manual and a qualified technician before performing repairs.