Solar · Error codes · SMA Solar Technology AG
8503SMA Solar Technology AG · Sunny Boy Smart Energy
8503 on a SMA Solar Technology AG Sunny Boy Smart Energy: Polarity error on the inverter
Short answer
On a SMA Solar Technology AG inverter, 8503 means: Polarity error on the inverter. The inverter keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Polarity error on the inverter.
Part involved: DC input polarity / string.
When it shows: Polarity error on the inverter.
Likely causes:
- SMA corrective measures: Check whether a string is connected to input C. If a string that once was connected is not used anymore, the string-failure detection must be reset. Contact Service.
Is it safe?
| Does the inverter stop? | Partly |
|---|---|
| Engineer needed? | Yes |
The inverter keeps running with some functions stopped.
Resetting itself: unknown.
Manual reset: See engineer checks.
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.
- Contact your installer - this concerns the DC string wiring.
What the engineer will check
- Check string connection/polarity on the named input, reverse currents, string design and module defects; reset string-failure detection if an input is no longer used; contact SMA Service.
Who to ask for: MCS 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 SMART ENERGY 3.6/4.0/5.0/6.0/8.0/9.9 ↗ · SBSExx-50-BE-en-12 Version 1.2 · page 97 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026