Warning What does this mean?
Your system is down or running degraded, but this is not an immediate safety danger. Work through the safe steps below.
Deye Inverter Error F15 — Is It Serious? How to Respond
Error F15 on a Deye inverter is an “AC firmware over current” fault — the inverter's software detected current on the AC side above its safe limit and shut down to protect itself. It often points to an internal sensing issue or a loose connection on the control board rather than a real overload in your home. Try the documented restart once; if F15 comes back, your installer needs to inspect the unit.
What should I do first?
Two quick questions — we'll point you to the right starting point.
Is this code still showing on your inverter's display?
Is your system producing power right now?
What this code means
In Deye's SUN series manuals, F15 is listed as “AC firmware over current.” That wording matters: it is the firmware — the inverter's own software — reporting that the measured AC current exceeded its programmed limit. The inverter responds the safe way, by stopping power feed-in and holding the fault until the condition is resolved. Nothing in your home caused this directly; the inverter is reacting to what its own sensors are telling it.
Deye's manual points at the likely culprit: the internal AC sensor, the detection circuit on the control board, or a loose connection wire. In plain terms, the inverter measures AC current with an internal sensor, and if that sensor, its circuit, or its wiring gives a wrong reading, the firmware sees a phantom overcurrent and trips F15 — even when the actual current is perfectly normal. A genuine AC-side overload or a sharp grid surge can also trip it, but the manual's own guidance steers toward the sensing hardware, and that hardware lives inside the unit.
Because the cause is usually internal, there is no homeowner fix beyond a single restart. A one-off F15 that clears after a restart and never returns was most likely a momentary glitch or a brief grid disturbance. An F15 that repeats — especially one that reappears within minutes of every restart — means the sensor, its wiring, or the control board needs professional attention. Do not keep restarting an inverter that trips F15 every time; leave it off and call your installer.
What is this downtime costing you?
Rough estimate while your system isn't producing. Adjust the numbers to match your setup.
≈ – kWh of lost production per day.
Estimate only — assumes ~80% real-world output vs. nameplate. Actual losses depend on weather, shading, panel direction, and your tariff.
Common causes
- Loose internal AC sensor or detection-circuit wiring on the control board — Deye's own listed cause; vibration and heat cycling can loosen connections over time.
- Faulty internal AC current sensor — a failing sensor reports current higher than reality, tripping the firmware limit even under normal load.
- Momentary AC surge or grid disturbance — a brief spike from grid switching or a nearby lightning strike can trip F15 once with no hardware fault behind it.
- Genuine AC-side overload or short — less common on a properly installed residential system, but a real overcurrent event on the AC wiring will also trip the protection.
- Control board fault — if the detection circuit itself is damaged, F15 repeats immediately after every restart.
Safe steps to try
Work top to bottom, ticking off each step as you complete it. 0 of 5 done.
Is your inverter still under warranty?
Before paying for a repair, check — your installer may fix this free.
Based on typical standard warranty terms — always confirm with your warranty card or installer paperwork, as terms vary by model, region, and purchase date.
When to call an electrician
Call your installer if F15 appears more than once, returns immediately after a restart, or shows up together with a tripped AC breaker. Deye's own troubleshooting ends at “restart the inverter; if the error still exists, contact your installer or Deye service” — there is no deeper homeowner step. Never open the inverter casing: internal components can carry dangerous voltage even with the unit switched off, and opening it voids the warranty. A technician will check the AC sensor, the control-board connections, and the AC wiring with the unit safely isolated.
Frequently asked questions
Can I keep using my inverter if F15 clears after a restart?
If it clears and stays clear, yes — a one-off trip after a grid disturbance is not unusual. But keep watching it: if F15 comes back within days, treat it as a developing hardware fault and call your installer instead of restarting repeatedly.
Is Deye F15 dangerous?
The fault itself is the inverter protecting itself, so it is not an emergency. But do not ignore a repeating F15 — it can signal a failing sensor or a real AC-side problem, and both deserve professional attention before they get worse.
My AC breaker tripped too — what should I do?
Leave the breaker off and call your installer or an electrician. A tripped breaker alongside F15 can mean a genuine overcurrent event on the AC wiring, and the wiring needs checking before anything is switched back on.
Will F15 damage my appliances?
No. The inverter shut itself down before any abnormal current could reach your home's circuits, so your appliances were never exposed to the fault. The protection did its job.
Need a professional?
This fault may need professional diagnosis. Contact a qualified solar electrician in your area.
Sources: meaning and troubleshooting verified against the manufacturer's documentation — Deye SUN-(3-10)K-G03 String Three-Phase Grid-Connected PV Inverter User Manual (English), official Deye manual hosted on deyeinverter.com — Section 10.1 Error code table: F15 = “AC firmware over current” (possible cause: internal AC sensor or detection circuit on control board, or connection wire may be loose; remedy: restart the inverter, contact installer if the error persists).