IVGM5-8K LP2G1 hybrid inverters (fault code list, solid fault LED)
Felicity 55 error code
INV under-voltage fault: the inverter's AC output voltage fell below its permitted range.
Likely causes
- Connected load exceeds what the inverter can hold voltage into
- Large motor or compressor starting on the backup output
- Undersized output cabling causing voltage drop
- Internal regulation fault
Checks to run, in order
- 1Measure output voltage at the inverter and at the load end
- 2Clamp the output current and compare with the inverter rating
- 3Isolate large motor loads and retest
- 4Check output cable size and terminations
Fixes
- Reduce the load or stagger motor starts
- Correct undersized or loose output cabling
- Restart and retest with a known load
When to escalate
If the output stays low with a small resistive load and correct cabling, escalate for inverter repair.
Fix it with the right tools
Check the system around the fault before replacing parts: load, battery bank, PV string and commissioning settings. If you need a second opinion, send the code and your inverter model to our team.
Before you open the inverter
- Isolate both the AC and DC sides, then confirm the display is dead before touching terminals.
- Use insulated tools and one hand where possible. DC arcs do not self-extinguish like AC.
- If you see burnt terminals, swollen cells, leaking electrolyte or a burning smell, stop and escalate instead of resetting the fault.
Questions installers ask
What does Felicity 55 mean?
INV under-voltage fault: the inverter's AC output voltage fell below its permitted range.
How do I fix Felicity 55?
Reduce the load or stagger motor starts Correct undersized or loose output cabling Restart and retest with a known load
When should I escalate Felicity 55?
If the output stays low with a small resistive load and correct cabling, escalate for inverter repair.
Can I reset Felicity 55 myself?
Only after isolating the AC and DC sides and running the checks above. If Felicity 55 returns immediately, stop resetting it and escalate; a repeating fault usually points to a real circuit, battery or hardware problem.
Which models show Felicity 55?
Felicity 55 is documented for IVGM5-8K LP2G1 hybrid inverters (fault code list, solid fault LED). Confirm the code on your own unit's display or manual before ordering parts.
More Felicity error codes
- Felicity 04Low cell voltage / over-discharge protection.
- Felicity 05PV over-current fault: the PV input current exceeded the inverter's PV input limit.
- Felicity 18PV short-circuit fault on the PV input; in the warning list the same number means battery under-voltage alarm.
- Felicity 19Battery open-circuit alarm: the inverter no longer detects a battery on its terminals.
- Felicity 20Battery SOC low alarm: the battery's state of charge has fallen to the low-SOC warning threshold.
- Felicity 21BMS communication alarm: abnormal communication between battery and inverter in non-SOC mode.
Guidance reviewed 17 October 2026 by the Mishka Energy installer team. Error codes vary by brand, model family and firmware; confirm against the manufacturer manual.
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