18xAB on a SolarEdge HD-Wave single-phase inverter: Over voltage Vin: Over voltage in DC input of the inverter. Check the strings' voltage
Short answer
On a SolarEdge inverter, 18xAB means: Over voltage Vin: Over voltage in DC input of the inverter. Check the strings' voltage. The inverter stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Over voltage Vin: Over voltage in DC input of the inverter. Check the strings' voltage.
Part involved: PV input over-voltage.
Likely causes:
- String voltage too high.
Is it safe?
Switch the inverter off at its isolator and call an engineer.
| Does the inverter stop? | Yes |
|---|---|
| Severity | Safety lockout |
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: no.
Manual reset: yes, after string design is corrected.
What you can check
- Read and note the exact code and time from the inverter display or app (screenshot).
- Call the installer. Do not touch DC cabling.
- If the code persists, contact the installer. SolarEdge's list says 'OFF/ON to reconnect' for some codes - that means the inverter's own ON/OFF switch; only use it if your installer has shown you how. Never open the inverter or touch DC cables/connectors.
What the engineer will check
- Measure open-circuit string voltage (cold-weather Voc rise).
- Check string design against inverter max DC voltage.
- Check for mixed/incorrect module counts.
Who to ask for: PV installer / system designer.
Certification: Electrician competent in grid-connected PV (BS 7671 Section 712; IET Code of Practice for Grid-connected Solar PV), ideally the original MCS-certified PV installer; brand-approved/trained installer to keep manufacturer warranty.
What you might notice
Sources
- Troubleshooting SolarEdge Systems, Addendum (Europe & APAC) MAN-01-00333-1.2 ↗ · MAN-01-00333-1.2 · page PDF p.6 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026