43Fault

Felicity inverter error 43 (F43)

The battery voltage of each inverter is not the same

Also displayed as F43 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:

IVPS3524P1G1-LV

InverterFault

Also applies to:IVPS5048P1G1-LVIVPS7548P2G1IVPS10048P2G1IVPS3.5~10kVA-USIVPS3-5-10KVA

What it means

The battery voltage of each inverter is not the same — In the parallel system, the inverters measure different battery voltages.

Cause: The inverters do not share the same battery group, or the battery cables differ in length or material type.

How to fix it

  1. Make sure all inverters share the same groups of batteries.
  2. Remove all loads and disconnect the AC input and PV input, then check the battery voltage of all inverters.
  3. If the values from all inverters are close, check that all battery cables are the same length and material type; otherwise, contact your installer to provide the SOP to calibrate the battery voltage of each inverter.
  4. If the problem still remains, contact your installer.

Source: 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

BUS under voltage fault — When the power grid experiences an AC power outage, the device detects islanding proactively.

Cause: When raised as a fault, the internal DC bus failed to hold its working voltage. The same code number is used in the alarm list for active islanding detection after a grid outage.

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.52 · 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-6KLP1G01

What it means

Parallel CAN COMM abnormality

Cause: Communication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.

How to fix it

Test the parallel communication line, restart still have problems please contact the after-sales service.

Source: T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf, p.39

IVEM 6048

InverterFault

Also applies to:IVEM6048

What it means

Current feedback into the inverter is detected

Cause: Reverse-connected L/N cables or improper sharing-cable wiring in parallel/three-phase systems.

How to fix it

  1. Restart the inverter
  2. Check if L/N cables are not connected reversely in all inverters
  3. For parallel system in single phase, make sure the sharing cables are connected in all inverters. For supporting three-phase system, make sure the sharing cables are connected in the inverters in the same phase, and disconnected in the inverters in different phases
  4. 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

Current feedback into the inverter is detected

Cause: Reverse current feedback detected at the inverter.

How to fix it

  1. Restart the inverter
  2. Check if L/N cables are not connected reversely in all inverters
  3. For parallel system in single phase, make sure the sharing cables are connected in all inverters. For supporting three-phase system, make sure the sharing cables are connected in the inverters in the same phase, and disconnected in the inverters in different phases
  4. If the problem remains, please contact your installer.

Source: IVEM8K-12K-II_compressed.pdf, p.45

IVEM8048-LV

InverterFault

Also applies to:IVEM8048

What it means

Current feedback into the inverter is detected

Cause: Reverse-connected L/N cables, or sharing cables not connected/connected across phases in three-phase setup.

How to fix it

  1. Restart the inverter
  2. Check if L/N cables are not connected reversely in all inverters
  3. For parallel system in single phase, make sure the sharing cables are connected in all inverters. For supporting three-phase system, make sure the sharing cables are connected in the inverters in the same phase, and disconnected in the inverters in different phases
  4. If the problem remains, please contact your installer.

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

T-REX-10KHP3G01

InverterFault

What it means

CAN data loss — Loss of CAN bus communication data.

Cause: Communication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.

How to fix it

  1. Check if communication cables are connected well and restart the inverter.
  2. If the problem remains, please contact your installer.

Source: T-REX-10KHP3G01-Inverter-User-Guide.pdf, p.29

T-REX-10KLP3G01

InverterFault

What it means

CAN data loss

Cause: Communication cables not connected well.

How to fix it

  1. Check if communication cables are connected well and restart the inverter
  2. If the problem remains, please contact your installer.

Source: T-REX-10KLP3G01-Inverter-User-Guide.pdf, p.29

Apollo-5KLP1G01-MX

Energy storage systemFault

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

What it means

Parallel CAN COMM abnormality — Parallel CAN communication abnormality.

Cause: Parallel CAN COMM abnormality.

How to fix it

Test the parallel communication line, restart still have problems please contact the after-sales service.

Source: Apollo-5KLP1G01-All-in-one-ESS-User-Guide.pdf, p.44

Frequently asked questions

What does error 43 mean on a Felicity inverter?
It depends on the model — 9 devices use code 43. On the IVPS3524P1G1-LV it means: The battery voltage of each inverter is not the same. The card for each model on this page gives its exact meaning and fix.
Is error 43 a fault or a warning?
43 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 43?
Make sure all inverters share the same groups of batteries. Remove all loads and disconnect the AC input and PV input, then check the battery voltage of all inverters. The exact steps for each affected model are listed on this page.

Related error codes

Other codes on the IVPS3524P1G1-LV

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

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.