So, this is happening once in awhile in an ESS system. It happens when there is no PV on the quattro's output, and loads are low. There is nothing shown on the CCGX display that "syncs up" with the weird sound. All voltages, power numbers in and out are stable.
https://photos.app.goo.gl/FkrUdX7YyRXFzkNz7
Clues:
- increase loads, the cycling speeds up.
- When PV returns in the morning on the AC output, it stops doing this.
- If I turn both Quattros off and on again using the switch while there is load, this quattro's output stays on
- If I first remove the load from the output, then it turns off and on normally
- When reset the problem goes away until a few days later
- nobody is in the building when it happens, no special loads, just a dozen computers.
It kind of sounds a bit like relay chatter, but might just be the transformer coils. Should I discontinue use and warranty this one?
The LEDs are also behaving oddly. Why would both inverter's LEDs be in different states in a multi-phase system? They switch as group.
Help is greatly appreciated!