Hi,
i am implementing an ESS Mode 3 system with a MultiplusII 48/3000 and Cerbo GX.
Battery is a LiFePO4, 100Ah, CAN-BMS to Cerbo.
Gridcode is Germany, AR4105/LOM-B.
The Pwr setpoint is written via ModbusTCP, Addr 37 to the Cerbo, about 2-3 times per second.
Problem is, my ESS loop is swinging wildly, is unstable.
So for a test, i wrote a constant 10W or 100W setpoint (without the ESS loop). The result was the Cerbo/MultiplusII somewhat doing something. For 10W setting the result was a random fluctuation <100W, for the 100W setting it fluctuated somewhere at 100W+-50%.
The docs vaguely stays, some additional restrictions apply for ESS mode 3.
What are these restricitons/features?
- How often should i update the setpoint?
- What rate of change per second is recommended/resricted?
- How long does it take for the ModbusTCP setting to reach the MultiplusII and be active to the grid?
- How can i get feedback from the MultiplusII what actual value it is using?
- What additional rules/restrictions apply?
- What is the granularity of the setpoint, or how precise is it activated to the grid?
- Are there special restrictions if changing between charge and discharge? Should i implement a hysteresis?
- What other features are active, e.g. battery life optimizations? Minimum SoC?
TiA
Matthias
