28Fault

Felicity inverter error 28 (F28)

Current sensor is abnormal

Also displayed as F28 on some models.

Fault — the inverter cuts its output and the red LED stays solid until the fault is cleared.

The exact meaning depends on your model:

IVPS/IVPM Series

InverterFault

Also applies to:IVPS2512IVPS2524IVPS3524IVPS5024IVPS5048IVPS7548IVPS-7548IVPS10048+9

What it means

Current sensor is abnormal — The internal current sensor reports an abnormal value.

Cause: The inverter's internal current sensor returned an out-of-range or implausible reading, so the control board can no longer trust its output-current measurement.

How to fix it

Contact the repair center.

Source: IVPS-IVPM User Guide.pdf, p.17 · IVPS3524P1G1-LV IVPS5048P1G1-LV IVPS7548P2G1 IVPS10048P2G1 User Guide - EN.pdf, p.25

IVGM5KL-P1G1

InverterFault

Also applies to:IVGM6KL-P1G1IVGM7K6L-P1G1IVGM8KL-P1G1

What it means

Bat hardware overcurrent — Battery hardware over current detected.

Cause: The battery port's hardware overcurrent protection tripped — an instantaneous trip that acts independently of the firmware and reacts to fast surges or a near-short on the battery circuit.

How to fix it

  1. Restart the system 2~3 times
  2. If the fault still exists, please contact us for help.

Source: Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf, p.53

T-REX-3KLP1G01

InverterFault

Also applies to:T-REX-3K6LP1G01T-REX-4KLP1G01T-REX-4K6LP1G01T-REX-5KLP1G01T-REX-6KLP1G01T-REX-10KHP3G01T-REX-10KLP3G01

What it means

The DC component of the inverter current is abnormal

Cause: The DC component riding on the inverter's output current exceeded the permitted limit — the output waveform has developed an asymmetry, typically from an output-stage or current-feedback fault.

How to fix it

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

Source: T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf, p.38 · T-REX-10KHP3G01-Inverter-User-Guide.pdf, p.28 · T-REX-10KLP3G01-Inverter-User-Guide.pdf, p.28

IVEM 6048

InverterFault

Also applies to:IVEM6048

What it means

Single unit is installed to parallel system

Cause: A single unit configuration was installed where parallel was expected.

How to fix it

  1. Please check if single unit is installed to parallel system
  2. If this error happens during parallel installation, please check wires connectiotn. if they are connected correctly, please funish parallel installation first, and then restart inverters
  3. If the problem remains, please contact your installer.

Source: felicitysolar IVEM 6048 Solar Inverter User Guide.pdf, p.38

IVEM8048-II

InverterFault

Also applies to:IVEM12048-IIIVEM 8K-12K Series II

What it means

Single unit is installed to parallel system

Cause: A single unit is detected as installed in a parallel system.

How to fix it

  1. Please check if single unit is installed to parallel system
  2. If this error happens during parallel installation, please check wires connectiotn. if they are connected correctly, please funish parallel installation first, and then restart inverters
  3. If the problem remains, please contact your installer.

Source: IVEM8K-12K-II_compressed.pdf, p.44

IVEM8048-LV

InverterFault

Also applies to:IVEM8048

What it means

Single unit is installed to parallel system

Cause: Single unit configured into a parallel system, or wiring problem during parallel installation.

How to fix it

  1. Please check if single unit is installed to parallel system
  2. If this error happens during parallel installation, please check wires connection. if they are connected correctly, please funish parallel installation first, and then restart inverters
  3. If the problem remains, please contact your installer.

Source: FelicitySolar IVEM8048-LV Single Phase Hybrid Inverter User Guide.pdf, p.39

T-REX-50KHP3G01

InverterFault

What it means

Battery 1 relay short circuit fault — Battery 1 relay not properly disconnected causing short circuit, shutdown and restart.

Cause: A safety relay inside the inverter has failed self-test or is stuck. The inverter is designed to refuse grid connection in this state, so this is not an issue you can clear with restart cycles.

How to fix it

  1. This requires service — the relay assembly is not user-replaceable.
  2. Record the exact fault code and contact your installer or the manufacturer's service line.
  3. Do not bypass any safety interlock.

Source: T-REX-50KHP3G01-user-manual-.pdf, p.46

Apollo-5KLP1G01-MX

Energy storage systemCritical

Also applies to:Apollo-5KLP1G01-M1Apollo-5KLP1G01-M2Apollo-4K6LP1G01-MXApollo-4K6LP1G01-M1Apollo-4K6LP1G01-M2

What it means

The DC component of the inverter current is abnormal

Cause: The DC component of the inverter current is abnormal.

How to fix it

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

Source: Apollo-5KLP1G01-All-in-one-ESS-User-Guide.pdf, p.43

Frequently asked questions

What does error 28 mean on a Felicity inverter?
It depends on the model — 11 devices use code 28. On the IVPS/IVPM Series it means: Current sensor is abnormal. The card for each model on this page gives its exact meaning and fix.
Is error 28 a fault or a warning?
28 is a fault code: the inverter cuts its output and the red LED stays solid until it is cleared.
How do I clear or fix error 28?
Contact the repair center. The exact steps for each affected model are listed on this page.

Related error codes

Other codes on the IVPS/IVPM Series

All IVPS/IVPM Series codes All IVPS3524P1G1-LV codes

Other codes on the IVGM5KL-P1G1

All IVGM5KL-P1G1 codes

Other codes on the T-REX-3KLP1G01

All T-REX-3KLP1G01 codes All T-REX-10KHP3G01 codes All T-REX-10KLP3G01 codes

Other codes on the IVEM 6048

All IVEM 6048 codes

Other codes on the IVEM8048-II

All IVEM8048-II codes

Other codes on the IVEM8048-LV

All IVEM8048-LV codes

Prefer the full written guide? Read the complete Felicity inverter error-code guide

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