Fault

W03

Power is zero.

7 Devices that report this code

What does the W03 error code mean?

W03 on a Felicity unit indicates: Power is zero.. It is a fault-severity event that can appear on 7 different devices in the Felicity catalog. The same code may have slightly different recommended fixes depending on the device — the per-device sections below show the exact wording from each device's official manual.

This is a fault-severity code

Fault codes stop normal operation but the unit may attempt to recover. Common causes are out-of-range conditions (voltage, current, temperature) that require checking inputs and outputs before restart.

What triggers this code

W03 is triggered when the unit's protection or monitoring logic detects the specific condition described above. The exact trigger depends on the device — see the per-device sections for the official manual entry for each.

E-CHO-SI3KS2Inverter↗ view on device
W03Power is zero.Fault
Description

Output power is zero.

Source:E-CHO-SI3KS2-Operation-Manual.pdf · page 17
E-CHO-SI5KS2Inverter↗ view on device
W03Power is zero.Fault
Source:E-CHO-SI5KS2-Operation-Manual.pdf
E-CHO-SI8KS2Inverter↗ view on device
W03Power is zero.Fault
Source:E-CHO-SI8KS2-Operation-Manual.pdf
IVEM 6048Inverter↗ view on device
W03Low battery.Warning
Description

Warning: Low battery. Beep once every second.

Cause

The battery voltage is too low.

Recommended fix

The battery voltage is too low, it should be charging.

Source:felicitysolar IVEM 6048 Solar Inverter User Guide.pdf · page 36
IVEM8048-IIInverter↗ view on device
W03Low battery.Warning
Description

Warning: Low battery. Beep once every second.

Cause

Battery voltage is too low.

Recommended fix

The battery voltage is too low, it should be charging.

Source:IVEM8K-12K-II_compressed.pdf · page 42
IVEM8048-LVInverter↗ view on device
W03Low battery.Warning
Description

Warning: Low battery. Beep once every second.

Cause

The battery voltage is too low.

Recommended fix

It should be charging.

Source:FelicitySolar IVEM8048-LV Single Phase Hybrid Inverter User Guide.pdf · page 37
T-REX-50KHP3G01Inverter↗ view on device
W03Battery 1 undervoltage alarm.Fault
Description

Battery 1 voltage is too low, the battery should be charged.

Source:T-REX-50KHP3G01-user-manual-.pdf · page 44

Frequently asked about W03

What is the W03 error on Felicity?
W03 on a Felicity unit means: Power is zero.. It can appear on 7 different devices in the Felicity catalog. The cause and recommended fix are listed for each device on this page.
Can I clear the W03 code myself?
It depends on the severity. Warning-level codes can usually be cleared by following the recommended fix. Fault and critical codes often require checking the source condition first; if the code returns immediately after restart, escalate to authorized service.
Is the W03 fix the same on every device?
The cause is consistent — it's the same protection logic. The exact fix wording can differ per device because each official manual addresses model-specific context (input ranges, parallel-config notes, firmware revisions). Use the per-device section that matches your unit.
Where does this information come from?
Every entry is sourced directly from the official Felicity user manual for the affected device. The "Source" line at the bottom of each device's section shows the manual filename and page number.

Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.