IVGM5-8K LP2G1 hybrid inverters (fault code list, solid fault LED)
Felicity 77 error code
PV insulation impedance fault: the PV array's resistance to earth is below the safe threshold.
Likely causes
- Damaged PV cable insulation
- Water or moisture in a connector or junction box
- Inverter PE not connected to ground
- Dirty or degraded PV connectors
- Long, wet cable runs with damaged conduit
Checks to run, in order
- 1Check that the PV panels and inverter are firmly and correctly connected
- 2Check that the inverter's PE cable is connected to ground
- 3Measure insulation resistance from each string to earth
- 4Inspect connectors and cable runs for damage or water
Fixes
- Repair or replace damaged DC cabling and connectors
- Dry the array and reseal wet joints
- Restore the PE connection, then restart 2-3 times
When to escalate
If insulation resistance stays low after damaged cabling is repaired and the array is dry, escalate for a full string insulation test and inverter check.
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 77 mean?
PV insulation impedance fault: the PV array's resistance to earth is below the safe threshold.
How do I fix Felicity 77?
Repair or replace damaged DC cabling and connectors Dry the array and reseal wet joints Restore the PE connection, then restart 2-3 times
When should I escalate Felicity 77?
If insulation resistance stays low after damaged cabling is repaired and the array is dry, escalate for a full string insulation test and inverter check.
Can I reset Felicity 77 myself?
Only after isolating the AC and DC sides and running the checks above. If Felicity 77 returns immediately, stop resetting it and escalate; a repeating fault usually points to a real circuit, battery or hardware problem.
Which models show Felicity 77?
Felicity 77 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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