Bus voltage too low
Also displayed as F30 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:
Also applies to:IVCM2024 PROIVCM3024 PRO
Bus voltage too low — Bus voltage is too low.
Cause: The internal DC bus voltage fell below its minimum operating threshold: weak input power from the battery or PV side, or an internal bus-converter fault.
Restart the unit, if the error persists, contact the repair center.
Source: ICM.pdf, p.14
Also applies to:T-REX-3K6LP1G01T-REX-4KLP1G01T-REX-4K6LP1G01T-REX-5KLP1G01T-REX-6KLP1G01T-REX-10KHP3G01T-REX-10KLP3G01
Bus voltage is too low
Cause: The 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 rather than external wiring.
Restart the unit, if the error persists, contact the repair center.
Source: T-REX-3_3.6_4_4.6_5_6KLP1G01-hybrid-inverter-user-guide-English.pdf, p.38 · T-REX-10KHP3G01-Inverter-User-Guide.pdf, p.28 · T-REX-10KLP3G01-Inverter-User-Guide.pdf, p.28
Battery 1 soft start fault — Battery 1 fails to raise the input voltage normally, shutdown and restart.
Cause: Battery 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.
Source: T-REX-50KHP3G01-user-manual-.pdf, p.46
Also applies to:Apollo-5KLP1G01-M1Apollo-5KLP1G01-M2Apollo-4K6LP1G01-MXApollo-4K6LP1G01-M1Apollo-4K6LP1G01-M2
Bus voltage is too low
Cause: Bus voltage is too low.
Restart the unit, if the error persists, contact the repair center.
Source: Apollo-5KLP1G01-All-in-one-ESS-User-Guide.pdf, p.43
All T-REX-3KLP1G01 codes All T-REX-10KHP3G01 codes All T-REX-10KLP3G01 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.