18x3 on a SolarEdge HD-Wave single-phase inverter: Night mode: Night Mode is an inverter status indicating that the input voltage is below 6 V DC

What it means

The manual says: Night mode: Night Mode is an inverter status indicating that the input voltage is below 6 V DC.

Part involved: Low DC input (night mode).

Likely causes:

• Night / very low light (normal).
• In daylight: DC side not connected, DC isolator off, optimisers not producing, string fault.

Is it safe?

The inverter stops until the fault clears or is reset.

Resetting itself: yes - normal at night; at dawn the inverter wakes when DC voltage rises.

Manual reset: no.

What you can check

• Read and note the exact code and time from the inverter display or app (screenshot).
• Normal at night. If shown in full daylight, contact the installer.
• 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

• Test DC side / optimiser output (1 V per optimiser safety voltage).
• Check string connections.

Who to ask for: PV installer.

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

• Solar panels not generating at all

Sources

• User Guide: SolarEdge Inverters Error Codes and Troubleshooting, Version 1.1 (January 2026) ↗ · 1.1 · page PDF p.14 · Reviewed 24 September 2026

A code explains what the controller detected, not a confirmed root cause.

Reviewed: 24 September 2026