In one of my systems, I have a CerboGX, RS Solar, Fronius 3P inverter, VM-3P75CT and batteries.
The system is currently running without the Fronius, as the Multi RS already doesn’t regulate the system to 0.
Grid meter support: On
Grid parameters: Germany
Feed-in allowed
Maximum limit currently set to 180 W
ESS grid setpoint: 0 W
System: Stand-Alone L1
Grid meter set to Vector measurement 3P
The problem is that the limit is only regulated on L1.
So L1 is at -180 W, while L2 and L3 are importing power as normal. However, the system should be limiting the total power to -180 W.
The ESS correctly regulates the total power to 0 W when the 180 W limit is sufficient, or when I allow full feed-in and there is no PV surplus.
I’ve already set the meter to both Arithmetic and Absolute, but that made no difference.
I’ve also tried setting the RS Solar to single-phase system mode.
There’s still a Ferraris meter installed, so I can still try things out. That’s also why I’ve set it to -180 W, as this is the average value that keeps the meter more or less stationary.
What can I do to limit actual feed-in to 0 W across the sum of the three phases?
I don’t know the right solution, but perhaps as a workaround:
Use Node-RED to get the power from the electricity meter and pass it to the Cerbo via a virtual meter.
Only pass the total wattage there, not the individual currents / power readings.
I’d try removing the 180 W setting; in my opinion, it isn’t enough for proper regulation. What are the yellow-highlighted parameters set to on your system?
The ESS is working correctly. What isn’t working is the feed-in limit: it only applies to L1, not to the combined power across the three phases.
Grid feed-in is limited to 180 W, as described.
I don’t think I have the peak shaving setting, as the Multi RS handles this automatically based on the main fuse rating.
the feed-in limit is, in my understanding, device-specific. In other words, with a Multi it applies to just one phase, and with 3 devices it applies to all 3 phases.
I’d try removing all the changes you’ve made and setting this up via DC-coupled surplus feed-in.
I don’t think that’s possible, because it’s a Multi RS Solar. There is no ESS Assistant; it is built directly into the device and configured using VictronConnect.
There is only a feed-in limit here, but no DC-coupled surplus energy feed-in.
I’ve also built a system with 3x Multi RS Solar, so it’s three-phase, with the Victron VM-3P75CT as the grid meter.
The grid operator has set an export limit of 4 kW. Unfortunately, you have to set the export limit to 1333 W on each device. This means the phase with the most PV power is curtailed first, while at the same time the device with the least PV power might only be exporting 500 W, for example.
So far, all attempts to get around this somehow using Node-RED have failed.
I hope there’ll be an update at some point so that you don’t have to set the export limit on each device individually, but can set it as a total across all three phases instead. Does anyone know if there’s anything in the works?
If I’d known this beforehand, I’d have built the system with an MP-II 5k and Fronius AC-PV inverters.
Are you sure export limit is a total of 4kw equal distributed over the 3 phases or 4kw combined across the 3 phases? Then you coud have one phase 4 kw and two phases zero.
Quote from [1], he has the same problem. Possible solution:
“In the Cerbo-GX I found the setting “ESS max feed-in power” which is currently set to “-1”, no limits. This can be set to a positive number representing 100W units. Zero is not accepted.”
A 100 W feed-in isn’t zero feed-in, but perhaps it’s better than nothing.
I was just wondering whether you even have that option in the Cerbo, especially since the Fronius isn’t running yet.
There is an “ESS max feed-in power” setting (in NodeRed), and it is set to -1 by default.
I’ve just tried a few different values, but they don’t change the amount of power fed into the grid. So, with it set to “5”, it’s still currently feeding over 700 W into the grid on one phase (over 1,500 W in total). I’ve now changed it back to -1.
