This is the complete fault table for the Felicity FLA12100 Battery — all 14 codes from the official manual on one page. On this Felicity device, a fault code means the unit has entered protection and stopped normal operation; a warning leaves it running. The exact indication (LED pattern or display code) is listed per code below.
Last checked against the official manuals on July 10, 2026.
Battery overvoltage fault. LED pattern: LED1 FLASH, LED2 OFF, LED3 OFF, LED4 OFF (with FAULT mode: GREEN OFF, RED ON).
CauseThe total battery pack voltage rose above its rated protection value during charging, so the BMS stopped charging. The protection releases once the pack voltage returns to the rated range.
Recommended fixRestart the unit. if the error persists, contact the repair center.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Battery undervoltage fault. LED pattern: LED1 OFF, LED2 ON, LED3 OFF, LED4 OFF.
CauseThe total pack voltage fell below its rated protection value during discharging (over-discharge), so the BMS stopped supplying power. The protection releases once the voltage returns to the rated range.
Recommended fixRestart the unit. if the error persists, contact the repair center.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Cell overvoltage fault. LED pattern: LED1 ON, LED2 ON, LED3 OFF, LED4 OFF.
CauseAn individual cell reached its over-voltage protection value during charging, typically from cell imbalance letting one cell run ahead of the pack, so the BMS stopped charging.
Recommended fixRestart the unit. if the error persists, contact the repair center.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Cell undervoltage fault. LED pattern: LED1 OFF, LED2 OFF, LED3 ON, LED4 OFF.
CauseAn individual cell fell below its under-voltage protection value during discharging, usually deep discharge or a weak, imbalanced cell, so the BMS stopped supplying power.
Recommended fixRestart the unit. if the error persists, contact the repair center.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Charge overcurrent fault. LED pattern: LED1 ON, LED2 OFF, LED3 ON, LED4 OFF.
CauseThe charging current reached the BMS trigger value and stayed there for 15 seconds, activating charge overcurrent protection: the charger or inverter is pushing more current than the pack accepts. The battery disables both charging input and discharging output while in fault mode.
Recommended fixRestart the unit. if the error persists, contact the repair center.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Discharge overcurrent fault. LED pattern: LED1 OFF, LED2 ON, LED3 ON, LED4 OFF.
CauseThe discharging current reached the BMS trigger value and stayed there for 15 seconds, activating discharge overcurrent protection: the load or inverter is drawing more current than the pack's discharge limit. The battery disables both charging input and discharging output while in fault mode.
Recommended fixRestart the unit. if the error persists, contact the repair center.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
MOSFET over-temperature fault. LED pattern: LED1 ON, LED2 ON, LED3 ON, LED4 OFF.
Cause1. The inner temperature is over the limitation. 2. The ambient temperature may be too high.
Recommended fixCheck whether the ambient temperature is too high.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
MOSFET under-temperature fault. LED pattern: LED1 OFF, LED2 OFF, LED3 OFF, LED4 ON.
Cause1. The internal temperature is lower than the limit range. 2. The ambient temperature may be too low.
Recommended fixCheck whether the ambient temperature is too low.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Cell over-temperature fault. LED pattern: LED1 ON, LED2 OFF, LED3 OFF, LED4 ON.
CauseInverter internal temperature has exceeded the safe operating threshold. Causes include high ambient temperature, blocked cooling vents, failed cooling fan, or installation in direct sunlight.
Recommended fixRestart the unit. if the error persists, contact the repair center.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Cell under-temperature fault. LED pattern: LED1 OFF, LED2 ON, LED3 OFF, LED4 ON.
CauseInverter ambient temperature is below the minimum operating range. Most common in unheated outdoor installs in winter.
Recommended fixRestart the unit. if the error persists, contact the repair center.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Abnormal current sampling fault. LED pattern: LED1 ON, LED2 ON, LED3 OFF, LED4 ON.
CauseThe BMS current sensor or its sampling circuit returned an abnormal reading. This is an internal hardware fault in the current-measurement path, not an installation issue.
Recommended fixRestart the unit. if the error persists, contact the repair center.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Abnormal output impedance fault. LED pattern: LED1 OFF, LED2 OFF, LED3 ON, LED4 ON.
CauseThe BMS measured abnormal impedance on the battery's output path, commonly a loose or corroded output terminal connection, or a contactor or wiring issue.
Recommended fixRestart the unit. if the error persists, contact the repair center.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Parallel connection failure between battery units. LED pattern: LED1 ON, LED2 OFF, LED3 ON, LED4 ON.
CauseSingle unit may be installed to a parallel system, or wiring connection between parallel units is incorrect/incomplete.
Recommended fix1. Check if a single unit is installed to a parallel system. 2. if this error happens during parallel installation, check wire connections; if connected correctly, finish parallel installation first and then restart the unit. 3. if the problem remains, contact your installer.
Source:Felicitysolar FLA12100 12.5Kwh Battery Energy Storage System User Manual.pdf· page 1
Output loss fault. LED pattern: LED1 OFF, LED2 ON, LED3 ON, LED4 ON.
CauseThe battery's output path is interrupted: the circuit breaker is open or the fuse has blown.
Recommended fix1. Check whether the circuit breaker is closed. 2. Check whether the fuse is normal. 3. 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
Send us the code on your screen and a Felicity technician will reply with the exact steps for your unit. Support is free for life — a first diagnosis never needs a callout.
Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.