Hi,
I’m using a three phase system with am EM540.
I changed my Grid Set Point Up to actually -100W but If I look in the dashboard, there are time sequences with grid consumption up to 100W.
What can I do?
I’m using a Cerbo with Venus 3.54
If you will see that is the total of all phases, so not all the phases are the same. All switching between negative and positive.
It is trying to phase regulate.
The fluctuations are causes by some X capacitors. As well as other fators in your system.
Is everything in the system up to date?
Depending from your system size and changing grid voltages for the reason of switching loads in your neighbourhood, there is always any inaccuracy for the feed in power. You need to go significantly below Null to securely avoid purchasing any power.
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Yes th whole system is up to date. Sorry I didn´t metion before.
I have three MP2 5000 in my system.
What do you mean? L1 and L3 are negative all the time and L2 is positive on the grid.
Sum of all phases is also the mode of my official electricity meter. This mode is recommended and I did not understand how this could contribute to my problem.
I see the same values on my official meter as on the Cerbo. I am actually drawing electricity from the grid.
It is clear to me that the grid set point is never exactly reached but that you always oscillate more or less around this point.
During the day, when I have PV power, this works perfectly. But at night, when the system is supposed to balance the power demand, it seems to oscillate more around 0W than around the set value.
Maybe go a little lower. I run a -100 and it runs fine. I don’t export anything.
Right now with PV-Power, my grid feed-in is also round about -100W with a Grid setpoint of -100W.
But at night without PV I have this strange behavior as shown in my video, which is also recorded with a Grid Setpoint of -100W
The system will not rigidly hold a setpoint. It is a point around which the system will move, depending on load, grid conditions etc and will average out over time.
The inverters are low frequency so there is always a push/pull of power for ESS, for many reasons.
With multiphase regulation the system is also always shuffling power to maintain a net zero balance, so it will always fluctuate.
The only way to avoid any use of power from the grid is to disconnect it.
It does not behave like yours if you watch mine with a -100w setpoint. Mine is -150w to -50w. What happens at night if you set it lower, say -300w? Can you test it and show the result? Keep lowering it till you get a negative that will offset the usage.
As said… “Right now…” wich means during daytime , grid feed-in is moving somewhere between -20W and -150W.
And of course with normal, short jumps in positive, when the coffeemaker etc. starts working.
@nickdb
Because of the step limit of 400W/Second on the Victron System, I don’t talk about grid consumption when there are big load changes.
I talk about a more or less (±50W) constant load while the grid consumption is moving around 0W instead of -100W as setted.
Behavior during daytime.
I dont have a codec to view that video. Yeah at night what happens when you set it even lower than -100w like -300w for example. Can you test that and post it?
Shure. I will test it and post the result.
And here the result with -400W.
No affect
But now! I turned off DESS.
After that, everthing was fine and working as expected.
I don’t unterstand why you ask.
The behavior is changing obviusly between day and night.
But to be clear, there is no limitation setted.
DESS overrides other behaviour, that would have been helpful to know in the original post.
If it works disabled, then leave it off. Too many other variables at play with that config.
@nickdb
I’m very sorry I figured it out today and not yesterday.
I have a dynamic price, so in winter time I have to use the DESS.
So turning off is 1. just a workaround for summertime and 2. wouldn’t help Victron.
Same problem here with 3x MP2 5000, 28kWh LiFePo4, dynamic pricing, 38kWp PV and daily consumption of ~40kWh.
Not beeing able to change the grid Setpoint to a negative value with DESS on costs me ~400€/a. Seems pointless to use it in the first place if it can’t make sure to avoid unneccessary grid consumption 
.
I found also some other threads.
DESS does everthing automatic. So the ESS setpoint has no affect to the DESS
I need to set grid feed in to around -80W to avoid unneccessary grid consumption. The Em24 Ethernet is a little bit off, i get billed around 1€/day while VRM shows nearly 2 kWh grid consumption. That adds up quickly and sould be easy to avoid.
Uhhh thats a lot.
I´m using a EM540 with a grid setpoit of -100W.
Per Day I have a consumption of 0,1kWh from Grid (without DESS)