3303 on a SMA Solar Technology AG Sunny Boy: There is not enough power at the DC input of the inverter for stable operation. The inverter cannot connect to the utility grid
Short answer
On a SMA Solar Technology AG inverter, 3303 means: There is not enough power at the DC input of the inverter for stable operation. The inverter cannot connect to the utility grid. The inverter keeps running with some functions stopped.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: There is not enough power at the DC input of the inverter for stable operation. The inverter cannot connect to the utility grid.
Part involved: DC input / irradiance.
When it shows: There is not enough power at the DC input of the inverter for stable operation. The inverter cannot connect to the utility grid.
Likely causes:
- SMA corrective measures: Ensure that the PV module is dimensioned correctly. Ensure that the PV module is not covered by snow or otherwise shaded. Ensure that the PV module is free of defects.
Is it safe?
| Does the inverter stop? | Partly |
|---|---|
| Severity | Information only |
| Engineer needed? | No |
The inverter keeps running with some functions stopped.
Resetting itself: yes.
Manual reset: Automatic when condition clears.
What you can check
- Read the event number and message in the SMA Energy app / Sunny Portal (ennexOS) or the inverter's web interface and note the date/time for your installer. A red LED on the inverter means an event has occurred.
- From the ground, check whether panels are covered by snow, leaves or heavy shading; wait for brighter conditions (do not go on the roof).
- This message is normal at dawn, dusk and in very dull weather.
What the engineer will check
- If shown in good light, check array sizing/string voltage against inverter start voltage, module defects, and 'Critical voltage to start feed-in' parameter.
Who to ask for: PV installer.
Certification: Qualified electrician (BS 7671; MCS-certified PV installer for work on the PV array/DC side).
What you might notice
Sources
- Operating manual SUNNY BOY 3.0/3.6/4.0/5.0/6.0 ↗ · SBxx-1AV-41-BE-en-21 Version 2.1 · page 92 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026