Felicity Solar T-REX-50KHP3G01 50kW Three-Phase Hybrid Solar Inverter
Price incl. VATAED 17,944
This is the complete fault table for the Felicity T-REX-50KHP3G01 Inverter — all 105 codes from the official manual on one page. 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 10 July 2026.
Price incl. VATAED 17,944
The voltage of the PV1 is too high, check the voltage of the string.
CauseThe open-circuit voltage of the PV1 string is above the inverter's permitted DC input range — typically a string configured with too many modules in series.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
The voltage of the PV2 is too high, check the voltage of the string.
CauseThe open-circuit voltage of the PV2 string is above the inverter's permitted DC input range — typically a string configured with too many modules in series.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
The voltage of the PV3 is too high, check the voltage of the string.
CauseThe open-circuit voltage of the PV3 string is above the inverter's permitted DC input range — typically a string configured with too many modules in series.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
The voltage of the PV4 is too high, check the voltage of the string.
CauseThe open-circuit voltage of the PV4 string is above the inverter's permitted DC input range — typically a string configured with too many modules in series.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
The current of the PV1 is too large, check the string current.
CauseCurrent from the PV1 string exceeded the input stage's protection limit — more current than that MPPT channel is rated to carry.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
The current of the PV2 is too large, check the string current.
CauseCurrent from the PV2 string exceeded the input stage's protection limit — more current than that MPPT channel is rated to carry.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
The current of the PV3 is too large, check the string current.
CauseCurrent from the PV3 string exceeded the input stage's protection limit — more current than that MPPT channel is rated to carry.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
The current of the PV3 string is too large, check the string current.
CauseCurrent from the PV4 string exceeded the input stage's protection limit — more current than that MPPT channel is rated to carry.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
Pv1 string positive and negative connection, check the string wiring.
CauseThe PV1 string is connected with positive and negative reversed, so the input stage blocks it until the string wiring is corrected.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
Pv2 string positive and negative connection, check the string wiring.
CauseThe PV2 string is connected with positive and negative reversed, so the input stage blocks it until the string wiring is corrected.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
Pv3 string positive and negative connection, check the string wiring.
CauseThe PV3 string is connected with positive and negative reversed, so the input stage blocks it until the string wiring is corrected.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Pv4 string positive and negative connection, check the string wiring.
CauseThe PV4 string is connected with positive and negative reversed, so the input stage blocks it until the string wiring is corrected.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 1 voltage is too high, the battery should be discharged.
CauseThe control firmware measured battery 1 voltage above the protection limit — the pack is overcharged or its configuration exceeds the inverter's battery range, and it should be discharged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 2 voltage is too high, the battery should be discharged.
CauseThe control firmware measured battery 2 voltage above the protection limit — the pack is overcharged or its configuration exceeds the inverter's battery range, and it should be discharged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 1 voltage is too high, the battery should be discharged.
CauseBattery 1 voltage tripped the hardware overvoltage protection, which acts independently of the firmware — the pack is above the permitted range and should be discharged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 2 voltage is too high, the battery should be discharged.
CauseBattery 2 voltage tripped the hardware overvoltage protection, which acts independently of the firmware — the pack is above the permitted range and should be discharged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 1 voltage is too low, the battery should be charged.
CauseBattery 1 voltage has fallen below the permitted range — the pack is deeply discharged and must be charged before normal operation resumes.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 2 voltage is too low, the battery should be charged.
CauseBattery 2 voltage has fallen below the permitted range — the pack is deeply discharged and must be charged before normal operation resumes.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 1 current is too large, check the battery charge and discharge power.
CauseThe control firmware measured battery 1 current above the protection limit — charge or discharge power beyond what that battery channel is rated for.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 2 current is too large, check the battery charge and discharge power.
CauseThe control firmware measured battery 2 current above the protection limit — charge or discharge power beyond what that battery channel is rated for.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 1 current is too large, check the battery charge and discharge power.
CauseBattery 1 current tripped the hardware overcurrent protection, which acts independently of the firmware — a fast surge in charge or discharge current on that channel.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 2 current is too large, check the battery charge and discharge power.
CauseBattery 2 current tripped the hardware overcurrent protection, which acts independently of the firmware — a fast surge in charge or discharge current on that channel.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 1 positive and negative poles is reversed, check the battery wiring.
CauseBattery 1 is connected with positive and negative poles reversed, so the battery stage blocks it until the wiring is corrected.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 2 positive and negative poles is reversed, check the battery wiring.
CauseBattery 2 is connected with positive and negative poles reversed, so the battery stage blocks it until the wiring is corrected.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 1 relay not closing properly causing open circuit, shutdown and restart.
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 fixThis requires service — the relay assembly is not user-replaceable. Record the exact fault code and contact your installer or the manufacturer's service line. Do not bypass any safety interlock.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 2 relay not closing properly causing open circuit, shutdown and restart.
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 fixThis requires service — the relay assembly is not user-replaceable. Record the exact fault code and contact your installer or the manufacturer's service line. Do not bypass any safety interlock.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 1 relay not properly disconnected causing short circuit, shutdown and restart.
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 fixThis requires service — the relay assembly is not user-replaceable. Record the exact fault code and contact your installer or the manufacturer's service line. Do not bypass any safety interlock.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 2 relay not properly disconnected causing short circuit, shutdown and restart.
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 fixThis requires service — the relay assembly is not user-replaceable. Record the exact fault code and contact your installer or the manufacturer's service line. Do not bypass any safety interlock.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 1 fails to raise the input voltage normally, shutdown and restart.
CauseBattery 1's input stage failed to raise its voltage to the working point during the soft-start ramp — an internal converter fault on that channel.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 2 fails to raise the input voltage normally, shutdown and restart.
CauseBattery 2's input stage failed to raise its voltage to the working point during the soft-start ramp — an internal converter fault on that channel.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 1 SOC is too low, the battery should be charged.
CauseBattery 1's state of charge has dropped below the protection threshold — the pack has too little usable energy left and must be charged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Battery 2 SOC is too low, the battery should be charged.
CauseBattery 2's state of charge has dropped below the protection threshold — the pack has too little usable energy left and must be charged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Bus voltage is too high, shutdown and restart.
CauseThe control firmware measured the internal DC bus above its protection ceiling — a regulation fault in the conversion stages or a surge fed in from the PV or AC side.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 46
Bus voltage is too high, shutdown and restart.
CauseThe internal DC bus tripped the hardware overvoltage protection, which acts independently of the firmware — a fast bus-voltage spike beyond the protection ceiling.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Bus voltage is too low, shutdown and restart.
CauseThe internal DC bus voltage fell below its operating range. The bus is regulated entirely inside the unit, so a persistent low reading points to an internal conversion-stage fault.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Positive bus voltage does not match negative bus voltage, shutdown and restart.
CauseThe positive and negative halves of the internal DC bus no longer match in voltage — an internal balancing fault in the conversion stages.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Bus voltage fails to rise normally at startup, shutdown and restart.
CauseThe DC bus failed to rise to its working voltage during the startup soft-start ramp — an internal converter or pre-charge fault.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Bus short, shut down and restart.
CauseA short circuit was detected on the internal DC bus — bus voltage collapsed while current spiked, which is an internal power-stage fault.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Balanced bridge current is too high, shutdown and restart.
CauseThe control firmware measured current in the bus-balancing bridge above its protection limit — the circuit that keeps the two bus halves matched is overloaded or faulty.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Balanced bridge current is too high, shutdown and restart.
CauseCurrent in the bus-balancing bridge tripped the hardware overcurrent protection, which acts independently of the firmware — a fast current spike in the circuit that keeps the two bus halves matched.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Inverter voltage fails to rise normally at startup, shutdown and restart.
CauseThe inverter stage failed to raise its output voltage to the working point during the startup soft-start ramp — an internal fault rather than a wiring issue.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Inverter voltage is too high, shutdown and restart.
CauseThe inverter stage's output voltage ran above the permitted range — an internal regulation fault rather than a wiring issue.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Inverter current is too high, check the given power and load size.
CauseThe control firmware measured inverter output current above its protection limit — the commanded power or the connected load is beyond what the unit can deliver.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Inverter current is too high, check the given power and load size.
CauseInverter output current tripped the hardware overcurrent protection, which acts independently of the firmware — a fast surge from the load side or a fault in the output stage.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Short circuit at inverter, shutdown and restart.
CauseA short circuit was detected at the inverter output: current spiked while voltage collapsed, pointing to a wiring fault or a shorted load.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Inverter voltage DC component is too high, shutdown and restart.
CauseA DC offset beyond the permitted limit was detected riding on the inverter's output voltage — the output stage is no longer producing a symmetrical sine wave.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Inverter current DC component is too high, shutdown and restart.
CauseA DC component beyond the permitted limit was detected in the inverter's output current — the output waveform has developed an asymmetry the unit is not allowed to feed to loads or the grid.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
The grid voltage is too high, check whether 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 disconnects until the grid returns to range.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
The grid voltage is too low, check whether 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 disconnects until the grid recovers.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
The grid frequency is too high, check whether the grid frequency is within the normal range.
CauseThe grid frequency is above the inverter's permitted operating window, so it disconnects until the frequency settles back into range.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
The grid frequency is too low, check whether the grid frequency is within the normal range.
CauseThe grid frequency is below the inverter's permitted operating window, so it disconnects until the frequency recovers.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
The grid phase sequence is reversed, check the grid phase sequence wiring.
CauseThe grid phase sequence at the AC terminals is reversed relative to what the inverter expects, so it cannot synchronise until the phase wiring order is corrected.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
The load of the grid access is too large, and the load should be reduced.
CauseThe load drawn through the grid connection exceeds the permitted level, so the inverter trips until the load is reduced.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
The inverter enters active islanding.
CauseGrid power was lost and the inverter's active islanding protection tripped — it detected it was about to energise a dead grid section on its own and disconnected.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
Grid three-phase voltage unbalance, check the grid three-phase voltage.
CauseThe three grid phase voltages are unequal beyond the permitted tolerance, so the inverter cannot run balanced grid-tied operation until the phase voltages are corrected.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
The load exceeds 110%, the load should be reduced.
CauseThe connected load has exceeded 110% of the inverter's rated output — the first overload tier; the load must be reduced.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 47
The load exceeds 125%, the load should be reduced.
CauseThe connected load has exceeded 125% of the inverter's rated output — a deeper overload tier that trips faster than the 110% level; the load must be reduced.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
The load exceeds 150%, the load should be reduced.
CauseThe connected load has exceeded 150% of the inverter's rated output — a severe overload tier; protection cuts the output until the load is reduced.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
The load exceeds 200%, the load should be reduced.
CauseThe connected load has exceeded 200% of the inverter's rated output — the deepest overload tier, treated as a near-short; protection cuts the output immediately.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Inverter emergency shutdown.
CauseThe emergency power off (EPO) input was triggered, commanding an immediate inverter shutdown.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Inverter device temperature is too high.
CauseThe power-stage IGBT temperature exceeded its protection limit — sustained high load, high ambient temperature, or restricted cooling.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
The ambient temperature of the inverter is too high.
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 fixPower down the inverter and let it cool. Inspect cooling vents and fan inlets for dust, leaves, or insect nests — clean with compressed air. Confirm the inverter is installed in a shaded, ventilated location with the manufacturer's required clearances on all sides. If the fan does not spin on restart, fan replacement is required.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Fan 1 is faulty, check whether the fan is normal.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixPower down the inverter and remove the cover (only if the unit is field-serviceable per the manual). Inspect the fan for debris and clean. If the fan does not spin freely or is noisy, replace it with the manufacturer's OEM part.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Fan 2 is faulty, check whether the fan is normal.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixPower down the inverter and remove the cover (only if the unit is field-serviceable per the manual). Inspect the fan for debris and clean. If the fan does not spin freely or is noisy, replace it with the manufacturer's OEM part.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Fan 3 is faulty, check whether the fan is normal.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixPower down the inverter and remove the cover (only if the unit is field-serviceable per the manual). Inspect the fan for debris and clean. If the fan does not spin freely or is noisy, replace it with the manufacturer's OEM part.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Fan 4 is faulty, check whether the fan is normal.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixPower down the inverter and remove the cover (only if the unit is field-serviceable per the manual). Inspect the fan for debris and clean. If the fan does not spin freely or is noisy, replace it with the manufacturer's OEM part.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Internal fan is faulty, check internal fan for is normal.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixPower down the inverter and remove the cover (only if the unit is field-serviceable per the manual). Inspect the fan for debris and clean. If the fan does not spin freely or is noisy, replace it with the manufacturer's OEM part.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
There was an error with the EEPROM write.
CauseA 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 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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Failure of 12V auxiliary power supply.
CauseThe internal 12 V auxiliary supply that powers the control and driver circuits has failed, so the inverter cannot keep its own electronics running reliably.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Current sensing device is faulty, check CT or Hall element connections.
CauseA current-sensing device (CT or Hall-effect sensor) reads open circuit — one of the inverter's current measurement paths is broken, so protection can no longer rely on it.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
There is an error in the DSP communication, try to upgrade the software.
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fixVerify the communication cable (CAN/RS485/Modbus) is correctly seated and the right pinout is used. Check baud rate and protocol settings in both devices match. Reseat the dongle/comms module. For BMS comms, confirm the battery is powered on and not in deep-discharge protection.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
There is an error in the MCU communication, try to upgrade the software.
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fixVerify the communication cable (CAN/RS485/Modbus) is correctly seated and the right pinout is used. Check baud rate and protocol settings in both devices match. Reseat the dongle/comms module. For BMS comms, confirm the battery is powered on and not in deep-discharge protection.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
The leakage current of the inverter is too large, check the wiring of the inverter.
CauseLeakage current to ground exceeded the safety limit — insulation or wiring on the DC or AC side is letting current return outside the normal conductors.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
The insulation of the PV string is abnormal.
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 fixDisconnect the PV strings and measure insulation resistance between PV+ and ground, PV- and ground, and PV+ to PV-. Any resistance below 1 MΩ indicates moisture or damaged insulation. Inspect MC4 connectors for water ingress. Reconnect each string one at a time to isolate the faulty string.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Battery 1 insulation is abnormal.
CauseThe insulation between the battery 1 circuit and ground measured below the safe threshold — damaged cable insulation or moisture in that battery's wiring.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Battery 2 insulation is abnormal.
CauseThe insulation between the battery 2 circuit and ground measured below the safe threshold — damaged cable insulation or moisture in that battery's wiring.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Inverter relay not closing properly causing open circuit, shutdown and restart.
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 fixThis requires service — the relay assembly is not user-replaceable. Record the exact fault code and contact your installer or the manufacturer's service line. Do not bypass any safety interlock.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Inverter relay not properly disconnected causing short circuit, shutdown and restart.
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 fixThis requires service — the relay assembly is not user-replaceable. Record the exact fault code and contact your installer or the manufacturer's service line. Do not bypass any safety interlock.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
The inverter is connected to abnormal parallel communication.
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fixVerify the communication cable (CAN/RS485/Modbus) is correctly seated and the right pinout is used. Check baud rate and protocol settings in both devices match. Reseat the dongle/comms module. For BMS comms, confirm the battery is powered on and not in deep-discharge protection.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 48
Parallel host disconnects from the system, check whether the hosts is normal.
CauseThe parallel host (master) inverter has disconnected from the system, so the group has lost its coordinating unit until the host is restored.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 49
PV current is too high, check string current.
CauseThe PV input's hardware overcurrent protection tripped — string current spiked above the trip threshold faster than the software limit reacts.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 49
BMS1 fails to communicate normally, check the BMS1 communication cable.
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fixVerify the communication cable (CAN/RS485/Modbus) is correctly seated and the right pinout is used. Check baud rate and protocol settings in both devices match. Reseat the dongle/comms module. For BMS comms, confirm the battery is powered on and not in deep-discharge protection.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 49
BMS2 fails to communicate normally, check the BMS2 communication cable.
CauseCommunication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Recommended fixVerify the communication cable (CAN/RS485/Modbus) is correctly seated and the right pinout is used. Check baud rate and protocol settings in both devices match. Reseat the dongle/comms module. For BMS comms, confirm the battery is powered on and not in deep-discharge protection.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 49
Bus voltage too high, shutdown and restart.
CauseThe PV-side DC bus voltage rose above its protection ceiling too quickly for normal regulation to respond — a fast transient overvoltage rather than a slow drift.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 49
Battery 1 voltage is too high and the battery should be discharged.
CauseBattery 1 voltage has climbed to the overvoltage alarm threshold — the warning stage before the overvoltage fault; the pack should be discharged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 44
Battery 2 voltage is too high and the battery should be discharged.
CauseBattery 2 voltage has climbed to the overvoltage alarm threshold — the warning stage before the overvoltage fault; the pack should be discharged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 44
Battery 1 voltage is too low, the battery should be charged.
CauseBattery 1 voltage has fallen to the undervoltage alarm threshold — the warning stage before the undervoltage fault; the pack should be charged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 44
Battery 2 voltage is too low, the battery should be charged.
CauseBattery 2 voltage has fallen to the undervoltage alarm threshold — the warning stage before the undervoltage fault; the pack should be charged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 44
Battery 1 SOC is too low, the battery should be charged.
CauseBattery 1's state of charge has dropped to the low-SOC alarm threshold — little usable energy remains and the pack should be charged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 44
Battery 2 SOC is too low, the battery should be charged.
CauseBattery 2's state of charge has dropped to the low-SOC alarm threshold — little usable energy remains and the pack should be charged.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 44
Entering high voltage ride-through at grid connection, the inverter sends reactive power to the grid.
CauseA grid voltage swell pushed the inverter into high-voltage ride-through: it stays connected and sends reactive power to the grid to support it instead of tripping offline.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 44
Entering low voltage ride-through at grid connection, the inverter absorbs reactive power from the grid.
CauseA grid voltage dip pushed the inverter into low-voltage ride-through: it stays connected and absorbs reactive power from the grid instead of tripping offline.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 44
The frequency is too low, the inverter reduce the power.
CauseGrid frequency has fallen below the derating threshold, so the inverter automatically reduces its output power while the condition lasts.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 44
The frequency is too high, the inverter reduce the power.
CauseGrid frequency has risen above the derating threshold, so the inverter automatically reduces its output power while the condition lasts.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 44
The frequency is too low, the inverter increases the power.
CauseGrid frequency has fallen below the response threshold and the inverter raises its output power to help support the grid while the condition lasts.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
The load is overloaded, and the load should be reduced.
CauseThe connected load has climbed above the inverter's rated output — the warning stage before the overload fault tiers cut the output; the load should be reduced.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
If the DC lightning protector is abnormal, check whether the lightning protector is abnormal.
CauseThe DC-side surge (lightning) protector is reporting an abnormal state — these modules commonly degrade after absorbing a surge and need to be checked.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
If the AC lightning protector is abnormal, check whether the lightning protector is abnormal.
CauseThe AC-side surge (lightning) protector is reporting an abnormal state — these modules commonly degrade after absorbing a surge and need to be checked.
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:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
The radiator temperature is too high, and the inverter reduces the power.
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 fixPower down the inverter and let it cool. Inspect cooling vents and fan inlets for dust, leaves, or insect nests — clean with compressed air. Confirm the inverter is installed in a shaded, ventilated location with the manufacturer's required clearances on all sides. If the fan does not spin on restart, fan replacement is required.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
The ambient temperature is too high, and the inverter reduces the power.
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 fixPower down the inverter and let it cool. Inspect cooling vents and fan inlets for dust, leaves, or insect nests — clean with compressed air. Confirm the inverter is installed in a shaded, ventilated location with the manufacturer's required clearances on all sides. If the fan does not spin on restart, fan replacement is required.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
Fan 1 stops abnormally, check fan wiring.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixPower down the inverter and remove the cover (only if the unit is field-serviceable per the manual). Inspect the fan for debris and clean. If the fan does not spin freely or is noisy, replace it with the manufacturer's OEM part.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
Fan 2 stops abnormally, check fan wiring.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixPower down the inverter and remove the cover (only if the unit is field-serviceable per the manual). Inspect the fan for debris and clean. If the fan does not spin freely or is noisy, replace it with the manufacturer's OEM part.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
Fan 3 stops abnormally, check fan wiring.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixPower down the inverter and remove the cover (only if the unit is field-serviceable per the manual). Inspect the fan for debris and clean. If the fan does not spin freely or is noisy, replace it with the manufacturer's OEM part.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
Fan 4 stops abnormally, check fan wiring.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixPower down the inverter and remove the cover (only if the unit is field-serviceable per the manual). Inspect the fan for debris and clean. If the fan does not spin freely or is noisy, replace it with the manufacturer's OEM part.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
Internal fan stops working abnormally, check internal fan wiring.
CauseInternal cooling fan failure detected. Often caused by dust buildup, bearing wear, or debris fouling the fan blades.
Recommended fixPower down the inverter and remove the cover (only if the unit is field-serviceable per the manual). Inspect the fan for debris and clean. If the fan does not spin freely or is noisy, replace it with the manufacturer's OEM part.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 45
Send us the code on your screen and a Felicity technician will reply with the exact steps for your unit. If the unit needs replacing, order it online.
Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.