ESS suddenly started oscillating after 2 years of stable operation
My ESS installation has worked fine for about two years. The problem appeared suddenly, without any changes to the configuration.
When I switch ESS on, it starts oscillating almost immediately. With ESS off, everything is stable.
I attached some VRM plots showing the MultiPlus output, ET340 power per phase, battery power and VE.Bus voltage/current.
I also tried reconnecting the USB connection between the ET340 and MultiPlus and reverted the MultiPlus to firmware 3.73. The behaviour did not change.
Any ideas what could cause this?
I am wondering whether the ET340 could be the problem. Would replacing it with an EM24 Ethernet be a sensible test?
thank you for your suggestion
I checked the jumper and it was solid
no external current sensor was connected. An ET340 is used to measure power to and from the grid.
To be honost I don’t see self-oscillation on your charts, only normal activity. An ESS waits for deviation from the grid setpoint to adds or subtracts power. It can only react if a deviation is present and the response will overshoot linear to the change of load to balance the totalizers. I believe you worry too much.
Thanks, but just to clarify: we weren’t at home, so the normal load was around 400 W. The battery discharge limit is 800 W and the charge limit is 1800 W. The oscillations occurred mainly at night, when there was hardly any change in the household load. That is why I’m puzzled by the oscillations.
Here a picture of the console. The ESS is on, the battery is almost full. Normally the battery would discharge to get the grid to zero.
So no oscillations here now, but ESS not doing what it is supposed to do.
(I will make a video of the console as soon as the ESS shows oscillations. Thank you for the suggestion).
