SolarEdge Error Codes Explained in Plain English

If you've opened your SolarEdge monitoring app and seen an error code, you're probably wondering what it means and whether you should be worried. Most SolarEdge error codes look like cryptic technical jargon — but they're actually telling you something important about your system's health.

This guide translates every common SolarEdge error code into plain English, explains what's happening with your system, and tells you exactly what to do about it.

Understanding SolarEdge Error Code Format

SolarEdge uses a numbering system for its error codes. In newer firmware versions (v3.19xx and later), you'll see codes in an "18x" format. Older firmware uses simpler 2-3 digit numbers. The prefix often tells you what category of issue you're dealing with:

• 1x codes — Normal status (night mode, startup)
• 2x codes — AC voltage and hardware issues
• 3x codes — DC voltage issues from your panels
• 18x codes — Hardware, safety, and critical faults
• 41x codes — Communication errors with optimizers

Normal Status Codes (No Action Needed)

Night Mode (1x, 01x) — Your inverter goes to sleep when there's no sunlight. This is completely normal at night and during heavy cloud cover. If you see this during a sunny day, that's when you should be concerned.

DC Mode (04x) — Your system is operating in DC mode. Normal operation, no action needed.

AC Voltage Errors

AC Overvoltage (2x, 18x37) — The voltage coming from your utility grid is too high. Your inverter shuts down to protect itself. This is usually a utility issue, not a problem with your solar system. If it happens frequently, contact your power company.

AC Undervoltage (18x38) — The grid voltage is too low. Same idea as above — typically a utility issue. Your inverter will reconnect automatically when voltage stabilizes.

DC Voltage Errors

DC Overvoltage (3x, 18xD8) — The voltage from your solar panels is too high. This can happen on very cold, sunny mornings when panel efficiency peaks. It usually resolves itself as panels warm up. If persistent, your system may need a configuration check.

Critical Safety Faults — Take These Seriously

Isolation Fault (18x, 18x86, 03x9a) — This means there's an electrical leak to ground in your system. Do not try to power cycle your inverter. This is a safety issue that requires a professional technician. Common causes include water damage, cracked cable insulation, or a failing power optimizer.

Arc Fault (18xC) — Your system detected dangerous electrical arcing, which is a fire hazard. Stop operation immediately and call a professional. This is one of the most serious error codes you can see.

Ground Fault / RCD (18x3D, 33x) — Ground current detected. This is a safety hazard. Contact SolarEdge support immediately and do not reset the inverter.

Temperature Errors

Over-Temperature (145, 18x75) — Your inverter is too hot. Make sure nothing is blocking the ventilation around it. Clean any dust off the heatsink fins. The inverter will resume operation once it cools down. If this happens frequently, the installation location may need to be evaluated.

Communication Errors

Optimizer Communication Lost (41x) — Your inverter can't talk to one or more power optimizers on your roof. This could be a wiring issue, a damaged optimizer, or just a temporary glitch. If multiple optimizers drop at once, it's more likely a communication cable issue than individual optimizer failures.

What Should You Do?

Error codes are your system asking for help. The longer they go unaddressed, the more energy production — and money — you lose. SolarDoctor monitors your system continuously and alerts you the moment something isn't right, so you can address issues before they cost you.