A pattern we see every summer: the inverter runs fine in the morning, stops around midday, and sometimes comes back in the evening. Generation is lost exactly when it should be highest — and the cause is almost always one of three things.
1. Grid voltage too high (the most common cause)
When your inverter exports power, it pushes local voltage up. At midday, with maximum generation, voltage can cross the inverter's upper limit (often 250V+), so the inverter disconnects to protect itself. It shows a grid over-voltage code. Undersized or long AC cables make it worse.
- Fix: measure voltage at the inverter terminals at midday
- Check AC cable sizing and terminations
- Adjust voltage settings within permitted limits where allowed
- In persistent cases, discuss feeder voltage with your DISCOM
2. Overheating / derating
Direct sun, blocked vents or a failing cooling fan push internal temperature up. The inverter limits output (derates) or shuts down to protect itself — classically in the afternoon heat. A shaded, ventilated position and clean fans usually solve it.
3. Export limit / zero-export settings
Plants with export control throttle at midday by design when household consumption is low. If shutdown matches your load profile rather than heat, check the zero-export configuration first.
What to do
- Note the exact time and the error code shown
- Check whether it happens only on hot, sunny days
- Record midday grid voltage if you can
- Do not keep restarting — repeated thermal or voltage trips stress the relay stage
Frequently asked questions
Is it okay to let the inverter restart itself every day?
Occasional restarts are survivable, but daily over-voltage or thermal shutdowns shorten the life of relays and power components. The underlying cause should be fixed.
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