Growatt Error 409: DC Bus Overvoltage
Error 409 means the voltage on the Growatt's internal DC bus went too high. The DC bus is the internal rail between the panels and the AC output, and an overvoltage there can stress the inverter. It can be linked to a high solar input voltage, so it is worth treating like its input-side relative, Error 202.
What it usually means
- High PV input voltage feeding through to the bus, especially on cold, bright mornings.
- A transient spike a restart can clear.
- An internal fault if it keeps returning with normal input.
What to do, safely
- If you also see Error 202 (PV voltage high), turn off the DC isolator, because your array may be over-volting the inverter. Check that page for the string-design fix.
- Otherwise, power-cycle once. AC breaker off, then the DC isolator, wait 5 minutes, restart. A transient Error 409 may clear.
- If it returns with normal input voltage, contact your installer or Growatt. A persistent DC bus overvoltage is an internal fault.
When to bring in a professional
A recurring Error 409 needs investigation: either your PV string voltage is too high (installer checks string design) or there is an internal bus fault (Growatt service). Don't keep reconnecting it blindly.
Related Growatt codes
Sources
- Growatt inverter user manual and error-code reference (Error 409 = bus overvoltage; restart, contact Growatt if it persists).
- Growatt installer documentation.
⚠️ Safety disclaimer. Solar inverters carry lethal DC and AC voltage even when "off", and PV inputs are live in daylight. This guide covers turning off the DC isolator and a single safe power cycle only. Internal faults and string changes must be handled by a licensed installer or Growatt technician.