54Fault

Felicity inverter error 54 (F54)

INV over voltage fault

Also displayed as F54 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:

IVGM5KL-P1G1

InverterFault

Also applies to:IVGM6KL-P1G1IVGM7K6L-P1G1IVGM8KL-P1G1

What it means

INV over voltage fault — Inverter over voltage fault.

Cause: The inverter measured its own AC output voltage above the permitted range — an internal regulation fault rather than a wiring issue.

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.54

T-REX-3KLP1G01

InverterFault

Also applies to:T-REX-3K6LP1G01T-REX-4KLP1G01T-REX-4K6LP1G01T-REX-5KLP1G01T-REX-6KLP1G01T-REX-10KHP3G01

What it means

Temperature sensor disconnected

Cause: An internal temperature sensor is no longer detected, so the inverter has lost a measurement it needs for thermal protection.

How to fix it

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

Source: t-rex-3-3.6-4.6-5-6klp1g01-user-guide-english.pdf, p.39 · T-REX-10KHP3G01-Inverter-User-Guide.pdf, p.29

T-REX-50KHP3G01

InverterFault

What it means

Grid Underfrequency Fault — The grid frequency is too low, check whether the grid frequency is within the normal range.

Cause: The grid frequency is below the inverter's permitted operating window, so it disconnects until the frequency recovers.

How to fix it

  1. Power down the inverter, wait 5 minutes for capacitors to discharge, then restart.
  2. If the fault recurs immediately or repeatedly, record the exact code and contact your installer or the manufacturer's service line.

Source: t-rex-25-50khp3g01-user-guide-en.pdf, p.47

Apollo-5KLP1G01-MX

Energy storage systemCritical

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

What it means

Temperature sensor disconnected

Cause: Temperature sensor disconnected.

How to fix it

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

Source: t-rex-5klp1g01-t-rex-6klp1g01-datasheet-en.pdf, p.44

Models that show 54

Frequently asked questions

What does error 54 mean on a Felicity inverter?

It depends on the model — 5 devices use code 54. On the IVGM5KL-P1G1 it means: INV over voltage fault. The card for each model on this page gives its exact meaning and fix.

Is error 54 a fault or a warning?

54 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 54?

1. Restart the system 2~3 times; 2. The exact steps for each affected model are listed on this page.

Related error codes

Other codes on the IVGM5KL-P1G1

54 is in the "Fault" class on the IVGM5KL-P1G1: 61 of the 61 codes documented for it.

All IVGM5KL-P1G1 codes

Other codes on the T-REX-3KLP1G01

54 is in the "Fault" class on the T-REX-3KLP1G01: 47 of the 47 codes documented for it.

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

Other codes on the T-REX-50KHP3G01

54 is in the "Fault" class on the T-REX-50KHP3G01: 105 of the 105 codes documented for it.

All T-REX-50KHP3G01 codes

Other codes on the Apollo-5KLP1G01-MX

54 is in the "Critical" class on the Apollo-5KLP1G01-MX: 27 of the 49 codes documented for it.

All Apollo-5KLP1G01-MX 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.