Hi everyone,
I have an installation with the following configuration:
- AC-coupled SolarEdge PV
- Multiplus II 5000
- Cerbo GX + VM-3P75CT
- 16kWh battery storage with Seplos BMS
- DESS running in Trade mode
- Dynamic tariff
Generally, it works fine - it charges from PV excess, creates a schedule, and discharges the battery during high tariff periods.
However, during discharge, the process “oscillates” (fluctuates) from about +100W to -3200W in roughly 15-second cycles.
When I disabled DESS and forced the grid setpoint to -3000, it ran smoothly at full capacity.
Is this normal behavior? If not, what could be the cause?
No, that’s not normal. There are some changes in the rate every now on then as the schedule is updated, or a soc-report is coming in - but it should never be that big and ofc not fall down to 0 during a discharge schedule.
Is your Solar-Edge PV “visible” to the system? I.e. does it know it’s momentary power production, or do you usually just relay on a grid-meter to absorb that additional solar power?
The later will not work for DESS, it needs to know the concrete production of attached ACPV to calculate proper setpoints throughout the system, as for DESS the grid will turn from a “measurement” to a “controlled value”.
What are your grid and battery settings in VRM?
Do you have setup either PeakShaving or AC-Current limits that may “mess” with these settings?
Do you have DVCC enabled on the GX? (That is required to be able to achieve a desired rate)