question

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rkrantz asked

AcPowerSetPoint not used, phase load always max

We have a Cerbo GX connected to three MultiPlus-II 48/3000/35-32 (one on each phase) in ESS mode 3 (external control) and a Pylontech battery.

We have been using this system to push and pull power to/from the grid using the following dbus paths on service com.victronenergy.vebus.ttyS4:

  • Hub4/L1/AcPowerSetpoint
  • Hub4/L2/AcPowerSetpoint
  • Hub4/L3/AcPowerSetpoint

By setting them to positive we charge the battery and setting them to negative we discharge the battery back to the grid. This has been working pretty well for a while until recently when we noticed that the AcPowerSetpoint value was not being used.

Regardless of what we set AcPowerSetpoint to, positive or negative, large or small, the actual AC grid value for each phase is always max input (in our case ~ 2 kW, or total ~ 6 kW), meaning we always charge the battery even though we tell it to discharge.

We have been setting these values using our own python service on the Cerbo but setting it manually in dbus-spy or directly with dbus -y produces the same result.

The only thing we think we can point to that could have changed is the firmware version on the Cerbo GX. But we tried to roll back to the previous version and also update to the latest but we still have the same problem. Below is the versions we have tried without any luck.

Cerbo GX:

  • when we discovered the issue: 2.90~10
  • rollback version: 2.80~29
  • current: 2.86

Multiplus:

  • 494

If anyone has any idea of what the issue could be, firmware or configuration, it would be much appreciated because we have run out of ideas and are stuck on this issue.

Multiplus-IIcerbo gxESS
2 |3000

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1 Answer
rkrantz avatar image
rkrantz answered ·

After some head scratching we figured out the issue.

We had one schedule set in ESS that was somehow interfering with our manual control of AcPowerSetpoint. We had to switch to Optimized so we could disable the schedule and switch back to external control. After that the system behaves as expected again, at least how we expect it to work. :)

Hope this helps if anyone runs into the same problem.

2 |3000

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