This is the complete fault table for the Felicity IVGM5KL-P1G1 Inverter family — 61 codes shared by 4 model numbers, transcribed from the official manual. On Felicity units, a fault code means the unit has cut its output and the red LED stays solid; a warning flashes the red LED while the unit keeps running.
Last checked against the official manuals on July 10, 2026.
PV input over current fault.
CauseA fault has been detected in the PV input stage — usually a short, ground fault, or isolation failure between the PV array and the inverter chassis. Wet connectors, damaged cable insulation, or moisture in a junction box are common causes.
Recommended fix1. 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· page 53
Battery voltage is too low, the battery should be charged.
CauseBattery voltage has fallen to the low-voltage alarm threshold — the pack is nearly depleted and needs charging before the inverter cuts off discharge.
Recommended fix1. 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· page 51Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 53
Battery open, check battery wiring.
CauseThe inverter no longer detects a battery on its terminals — the circuit reads open, typically a loose, broken or disconnected battery cable or a tripped battery breaker.
Recommended fixCheck battery wiring.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 51
Battery SOC is too low, battery should be recharged.
CauseThe battery's reported state of charge has dropped to the low-SOC alarm threshold, so there is little usable energy left in the pack.
Recommended fixRecharge the battery.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 51
Abnormal communication between battery and inverter in non-SOC mode, check battery and inverter wiring.
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fixCheck battery and inverter wiring.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 51
Battery voltage is too low or Battery SOC is too low, the battery should be charged.
CauseEither the measured battery voltage or the reported state of charge has fallen to the low-battery threshold — the pack is close to empty and must be recharged.
Recommended fixPower down the inverter, wait 5 minutes for capacitors to discharge, then restart. If the fault recurs immediately or repeatedly, record the exact code and contact your installer or the manufacturer's service line.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 51
Battery voltage exceeds specification.
CauseThe voltage at the battery terminals exceeds the inverter's specified battery range — usually a pack whose configuration or specification does not match the inverter, or a charge source pushing the pack too high.
Recommended fix1. Check the Battery voltage is in the range of standard voltage in specification; 2. Check whether Battery cables are firmly and correctly connected; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 53
Battery over current fault.
CauseCurrent into or out of the battery exceeded the software protection limit, so the inverter tripped to protect the pack and its own power stage.
Recommended fix1. 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· page 53
Battery hardware over current detected.
CauseThe 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.
Recommended fix1. 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· page 53
LLC converter hardware over current fault.
CauseThe hardware protection on the LLC converter stage (the isolated DC link inside the inverter) tripped on overcurrent.
Recommended fix1. 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· page 53
BMS communication failure between battery and inverter.
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fix1. Check whether BMS communication cable is firmly and correctly connected; 2. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 53
Grid voltage is too high, check if the grid voltage is within the normal range.
CauseThe grid voltage measured at the AC terminals is above the inverter's permitted operating window, so it alarms and holds off grid-tied operation until the voltage returns to range.
Recommended fixCheck if the grid voltage is within the normal range.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 51
Grid voltage is too low, check if the grid voltage is within the normal range.
CauseThe grid voltage measured at the AC terminals is below the inverter's permitted operating window, so it alarms and holds off grid-tied operation until the voltage recovers.
Recommended fixCheck if the grid voltage is within the normal range.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 51
Grid frequency is too high, check if the grid frequency is within the normal range.
CauseWhen raised as a fault, the buck-boost converter's current sensor has returned a reading the control board cannot trust. The same code number is used in the alarm list for grid frequency running above the permitted range.
Recommended fix1. 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· page 51Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 53
Grid frequency is too low, check if the grid frequency is within the normal range.
CauseThe grid frequency measured at the AC terminals is below the permitted operating window, so the inverter alarms and holds off grid-tied operation until the frequency recovers.
Recommended fixCheck if the grid frequency is within the normal range.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 51
LLC converter soft start failure.
CauseThe LLC converter stage failed to ramp up to its working point during soft start — an internal converter fault rather than a wiring issue.
Recommended fix1. 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· page 53
Grid phase sequence reversed, check grid phase sequence wiring.
CauseThe phase sequence the inverter detects at its grid terminals is reversed relative to what it expects, so it cannot synchronise until the grid wiring order is corrected.
Recommended fixCheck grid phase sequence wiring.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52
Battery port short circuit detected.
CauseThe inverter detected a short circuit — a near-zero-resistance path — across the battery port and shut down to protect the pack and its own power stage.
Recommended fix1. Check whether the battery port is in short circuit; 2. if the fault still exists, please contact us for help.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 53
DC bus over voltage fault.
CauseThe internal DC bus voltage exceeded its protection ceiling — typically a regulation fault in the conversion stages or a surge fed in from the PV or AC side.
Recommended fix1. 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· page 53
When the power grid experiences an AC power outage, the device detects islanding proactively.
CauseWhen 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.
Recommended fix1. 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· page 52Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 54
Entering LVRT at grid connection, the inverter absorbs reactive power from the grid.
CauseWhen raised as a fault, the positive and negative halves of the internal DC bus have drifted apart in voltage. The same code number is used in the alarm list for low-voltage ride-through, where the inverter absorbs reactive power during a grid dip.
Recommended fix1. 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· page 52Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 54
The load is overloaded and should be reduced.
CauseThe load on the backup output exceeds the inverter's continuous rating, so it raises the overload alarm before protection cuts the output.
Recommended fixPower down the inverter, wait 5 minutes for capacitors to discharge, then restart. If the fault recurs immediately or repeatedly, record the exact code and contact your installer or the manufacturer's service line.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52
Inverter software over current fault.
CauseThe control software measured inverter output current above its protection limit — usually loads beyond the rated range, or a surge the inverter could not ride through.
Recommended fix1. Please check whether the load power is within the range; 2. Restart and check whether it is in normal; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 54
Inverter hardware over current fault.
CauseThe inverter stage's hardware overcurrent protection tripped — an instantaneous trip, independent of the firmware, that reacts to fast surges or a short on the output side.
Recommended fix1. Please check whether the load power is within the range; 2. Restart and check whether it is in normal; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 54
Inverter soft start failure.
CauseThe inverter stage failed to ramp its output up to the working point during soft start — an internal fault rather than a wiring issue.
Recommended fix1. 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· page 54
DC component detected in AC voltage output.
CauseA DC offset beyond the permitted limit was detected riding on the AC output voltage — the output stage is no longer producing a symmetrical sine wave.
Recommended fix1. 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· page 54
DC component detected in AC current output.
CauseA DC component beyond the permitted limit was detected in the AC output current — the output waveform has developed an asymmetry the inverter is not allowed to feed to loads or the grid.
Recommended fix1. 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· page 54
Inverter over voltage fault.
CauseThe inverter measured its own AC output voltage above the permitted range — an internal regulation fault rather than a wiring issue.
Recommended fix1. 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· page 54
Inverter under voltage fault.
CauseThe inverter's AC output voltage sagged below the permitted range — most often the connected load exceeds what the unit can hold voltage into, otherwise an internal regulation fault.
Recommended fix1. Please check whether the load power is within the range; 2. Restart and check whether it is in normal; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 54
Inverter output short circuit fault.
CauseThe inverter detected a short circuit on its output: current spiked while voltage collapsed, pointing to a wiring fault or a shorted load on the backup circuit.
Recommended fix1. Please check the connection of buckup is firmly and correctly; 2. Restart and check whether it is in normal; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 54
Generator voltage is too high, check whether the generator voltage is within the normal range.
CauseThe voltage measured at the generator input is above the permitted operating window, so the inverter will not qualify generator power until it returns to range.
Recommended fix1. Please check whether the load power is within the range; 2. Restart and check whether it is in normal; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 54
Generator voltage is too low, check whether the generator voltage is within the normal range.
CauseThe voltage measured at the generator input is below the permitted operating window, so the inverter will not qualify generator power until it recovers.
Recommended fix1. Please check whether the load power is within the range; 2. Restart and check whether it is in normal; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 54
Generator frequency is too high, check whether the generator frequency is within the normal range.
CauseThe frequency measured at the generator input is above the permitted operating window, so the inverter alarms and will not qualify the generator until its frequency settles.
Recommended fixCheck generator output frequency.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52
Generator frequency is too low, check whether the generator frequency is within the normal range.
CauseThe frequency measured at the generator input is below the permitted operating window, so the inverter alarms and will not qualify the generator until its frequency recovers.
Recommended fixCheck generator output frequency.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52
Generator phase sequence reversed, check generator phase sequence wiring.
CauseThe phase sequence at the generator input is reversed relative to what the inverter expects, so generator power cannot be qualified until the wiring order is corrected.
Recommended fixCheck generator phase sequence wiring.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52
Heatsink over-temperature fault.
CauseInverter internal temperature has exceeded the safe operating threshold. Causes include high ambient temperature, blocked cooling vents, failed cooling fan, or installation in direct sunlight.
Recommended fix1. Check whether the work environment temperature is too high; 2. Turn off the inverter for 15mins and restart; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 54
Please check whether the load on backup port exceeds the generator specifications.
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fix1. 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· page 52Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 55
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fix1. 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· page 55
EEPROM fault.
CauseA read/write error occurred in the EEPROM that stores the inverter's settings and calibration, so the control board cannot reliably save or recall its configuration.
Recommended fix1. 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· page 55
CauseThe sensor that monitors AC leakage (residual) current returned an implausible reading, so the inverter can no longer verify that its leakage protection is working.
Recommended fix1. 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· page 55
AC leakage current detected.
CauseLeakage (residual) current to ground exceeded the safety limit — commonly degraded PV insulation or a grounding fault on the array cabling.
Recommended fix1. Check PV side cable ground connection; 2. Restart the system 2~3 times; 3. if the fault still exists, please contact us for help.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 55
Grid relay open circuit detected during self-check.
CauseA 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.
Recommended fix1. 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· page 55
Inverter relay self-check fault.
CauseA 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.
Recommended fix1. 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· page 55
Generator relay self-check fault.
CauseA 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.
Recommended fix1. 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· page 55
PV insulation impedance is too low.
CauseThe pre-start insulation test measured PV-array-to-ground resistance below the safe threshold — usually damaged cable insulation, moisture in connectors, or a missing PE connection.
Recommended fix1. Check the connection of PV panels and inverter is firmly and correctly; 2. Check whether the PE cable of inverter is connected to ground; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 55
Grid is incorrectly connected to backup port.
CauseGrid voltage was detected on the backup (load) port — utility wiring has been landed on the backup terminals instead of the grid port.
Recommended fix1. Check whether Backup cables are firmly and correctly connected; 2. Restart the system 2~3 times; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 55
Generator/Grid wrongly connected when smart load mode is set.
CauseThe GEN port is configured as a smart-load output, but the inverter detects a generator or grid source feeding into that port — the wiring contradicts the selected mode.
Recommended fix1. Check whether GEN cables are firmly and correctly connected; 2. Restart the system 2~3 times; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 55
NTC temperature sensor open circuit.
CauseAn internal NTC temperature sensor reads open circuit, so the inverter has lost a temperature measurement it needs for thermal protection.
Recommended fix1. 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· page 55
The inverter will reduce power if the heat sink temperature is too high.
CauseThe heat-sink temperature has climbed to the derating threshold, so the inverter reduces output power to hold it there — poor ventilation or high ambient temperature is the usual reason.
Recommended fixImprove ventilation; reduce ambient temperature.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52
External CT (current transformer) sensor fault.
CauseThe external current transformer (CT) used for export and consumption metering is not returning a valid signal — disconnected, mis-wired, or faulty.
Recommended fix1. Check the connection of CT is firmly and correctly; 2. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 55
Grid setting or Bat setting change, and the system will restart after 20ms.
CauseA grid or battery configuration setting has just been changed; the inverter reports this code while it restarts (about 20 ms) to apply the new parameters.
Recommended fixWait for system restart after parameter change.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
Fan 2 malfunction, check fan for proper functioning.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fix1. Please check whether External RSD signal triggers shutdown; 2. if not, restart the inverter; 3. if the fault still exists, please contact us for help.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
CauseAnother inverter in the parallel group is in a fault state, so the whole group reports a system-level error until that unit recovers.
Recommended fix1. Please check whether other inverter is in error state; 2. Restart the system; 3. if the fault still exists, please contact us for help.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
Parallel CAN communication failure.
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fix1. Check whether Parallel cables are firmly and correctly connected; 2. Restart the system 2~3 times; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
Parallel host inverter lost.
CauseThe paralleled units have lost contact with the host (master) inverter — usually a parallel communication cable fault or the host powering down.
Recommended fix1. Check whether Parallel cables are firmly and correctly connected; 2. Restart the system 2~3 times; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
Parallel synchronization signal lost.
CauseAs an alarm this reports the unit being shut down from its power button. The same code number is used in the fault table for loss of the parallel synchronization signal between units, which is why the recommended check is the parallel cabling.
Recommended fix1. Check whether Parallel cables are firmly and correctly connected; 2. Restart the system 2~3 times; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
Parallel inverters have inconsistent software versions.
CauseThe paralleled inverters are running different firmware versions; the parallel protocol requires every unit on the link to match before the group will run.
Recommended fix1. Check whether the software version of the inverter is same; 2. Restart the system 2~3 times; 3. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
Flash is not burned, contact the maintenance centre.
CauseThe inverters in the parallel group are not running identical parallel settings, so the group cannot form. The related fault-table entry covers a control board whose firmware flash was never programmed, which needs the maintenance centre.
Recommended fix1. Check whether Parallel cables are firmly and correctly connected; 2. Check whether the software version of the inverter is same; 3. Restart the system 2~3 times; 4. Seek help from us, if can not go back to normal state.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 52Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
CAN ID of different inverters is in conflict.
CauseTwo or more inverters on the parallel CAN bus are set to the same CAN ID — or two units are both configured as master in one phase — so their messages collide.
Recommended fix1. Please check whether CAN ID of different inverters is same; 2. Please check whether there are two masters in one phase.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
CauseThe hardware PWM synchronization signal shared between paralleled units has dropped out — almost always a parallel cable that is loose, damaged, or wrongly seated.
Recommended fix1. Please check whether the parallel cables are well-connected; 2. Restart the system; 3. if the fault still exists, please contact us for help.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
Grid phase sequence is abnormal.
CauseThe grid phase sequence measured at the terminals does not match the expected order, so the inverter cannot synchronise to the grid until the wiring order is corrected.
Recommended fix1. Please check whether the grid wires are well-connected; 2. Please check whether the grid phase sequence is correct; 3. Restart the system; 4. if the fault still exists, please contact us for help.
Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf· page 56
Send us the code on your screen and a Felicity technician will reply with the exact steps for your unit. Support is free for life — a first diagnosis never needs a callout.
Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.