For my ESS with grid meter everything behaves like expected. To feed in power to the grid, it is possible to set the grid setpoint to negative values. System feeds into grid, as long as there is power from the battery. Positive values for the grid setpoint will charge battery from grid. If battery is full, available excess power is feed into the grid although the grid setpoint is lower.
To avoid triggering the fuse of a week grid connection, I like to limit the maximum inverter power what is available to feed into the grid. The values of „maximum inverter power“ have always positive sign. Therefore they only limit the charging values for grid setpoint. They cannot limit the negative values for grid feed in.
Using Grid feed-in → Limit system feed-in instead, also cannot solve this problem. The positive value of Maximum feed-in can be always overwritten by entering a greater Grid setpoint value.
It limits the power that can be used for grid feeding in ESS. I do this—I have a 12V, 24V, and 48V ESS. If I don’t want to empty the 12V or 24V system, I will reduce the inverter power to something like 400W, and that is all it gives. Is there something specific you want to do or some sort of automation?
Why don’t you use inverter parameter “Grid Current Limit”?
With 3 phase system I have no other options because if you have solar and load and can also feed from battery, these phases can be uneven.
I just tested it and it is for both directions. Set that to 6A and then gridsetpoint to -9000W and this is the result
“Grid current limit” in Ampere seems something else than “Maximum feed-in” in Watt.
@owenb79 Yes, I like do some sort of automation regarding the German EEG §9 law where the feed into public grid needs to be limited by 4 external controlled relay contacts to 60% and 30%.
I am aware of the problem with asymmetric loads and “Grid(phase) current limit” is probably the best choice. For unknown reasons, I do not have access to this parameter using the predefined setups from Victron for Node Red.
Nevertheless, EEG §9 limits the power to the Grid, while VDE gives a maximum threshold for the current. All German grid counters are only aware for the total of all 3 phases why power limit should be a feasable method.
As we can see, the „maximum inverter power is set to 5000 Watt while grid setpoint shows the double of 10000 Watt. I checked again, and truthfully, the feed in power is limited to about 5000W. Possibly my monitoring with current clamp was wrong yesterday (or requires something like a Venus reboot to become true?).
This behaviour is ok for the moment. If „maximum inverter power“ goes back to a higher value, the grid feed in also goes back if grid setpoint is that high. Nevertheless, I expect same behaviour for the “Limit system feed in”. This would allow high inverter power, high self consumption but only low grid feed in. As we see, there is a limit of 1000 Watt only. ESS does not respected the limit and goes on feeding 5000 Watt to the grid.
No. This is the one I tried without success. Value appears in the menue, but is not limiting the Grid Feed in power. Therefore I assumed its not a Node Red problem but any unregarded dependance with the ESS.
Normally there is a array of Multis. Therefore the phase current needs to be an aggregated current for the array. Your blue node is the phase output current at the input 1 of all Multiplus. This is not necessarily same than the grid feed in current as there can be heavy AC loads between. Therefore your orange node is the (aggregated) phase current at the grid counter. This has the benefit to allow higher power production for self consumption by AC loads behind the grid counter ?
Try this flow and see if it works for you. This will check the total power and if its below -1000 set the max inverter power to 5000. If its above -1000 set the inverter power to 22000. Its pretty easy to see how the function works and make changes to the values.
