I can see a discussion about a similar problem now, with a solution involving downgrading Venus OS to 3.33: there seems to be something wrong with the Victron software: Hub4Mode spontaneously reverts to a fallback value during normal ESS Optimized operation, causing severe AC power oscillation
see: https://github.com/victro…57?utm_source=chatgpt.com
Thanks for this information.
Over the last few days there was a storm, and the EDF circuit breaker (500 mA) tripped, while the system continued to operate properly in autonomous mode.
When I restored the mains supply to ACIN, my system started oscillating (with Venus 3.33).
This is probably not a problem with the Venus version, but something else.
When you reconnected ACIN, was ESS enabled at that moment?
Hello,
Thanks to the post in German, “Poor control behaviour or overshoot on the ESS”, I found a solution that works.
https://community.victronenergy.com/uploads/short-url/1yGMSZUMRc0yyHJiYgkQ5rkwZPm.pdf
The issue was a poor connection at the Multiplus current-measurement jack socket.
After plugging and unplugging the jack (and applying a little contact cleaner), the ESS system works normally with the mains connected to ACIN.
For now, I have stayed on Venus 3.14, but I will update it to 3.75 and keep you posted.
Thanks Jeanvert for the suggestion. I powered down the Multiplus first. After inserting and removing a headphone jack plug five times, the ESS now seems to be working normally. Of course, the question is for how long, so I’ll leave it running for a day or two before concluding that this has actually solved the problem.
If this turns out to be the solution, it must be one of the most bizarre ones I’ve come across: an unused contact causing oscillations with power swings of up to 4000 W, despite the system being limited to 800 W. I’m very glad this didn’t result in a fire.
Closing the case – problem appears to be solved
The system has now been running stable for several days without any recurrence of the oscillations.
The apparent solution was the Current Sense jack. Although no external current sensor is used, I switched off the MultiPlus and inserted/removed a 3.5 mm jack plug several times, following the information Jeanvert pointed me to.
After restarting the system, the ESS immediately behaved normally again and has remained stable since.
Many thanks to Jeanvert and everyone else who contributed. I will consider the issue solved.