Hi,
I have got a 3 fase Multiplus 2 system, Cerbo gx, 4 DYNESS DL5.0C batteries and running DESS.
Everything is on AC out1, including my SMA solar inverter.
I installed a VM-3P75CT as a grid meter and set ESS grid metering to external meter.
Now my calculation of consumption is wrong.
I think it adds up the solar energy that goes into the battery with my actual consumption.
Can someone please point me in the right direction how to solve this?
Thx!
Can you check the Role of your meter? Is it set to âGridâ? What kind of Multiphase-Mode are you using? Individual or âTotal of all phasesâ? Make sure you select the matching measurement method in the VM-3P75CT as well.
Itâs on Grid, ESS is on âtotal of all fasesâ.
I think it is set up correct.
My Multiplus 2 inverters are still running firmware v498. Could this be the problem?
I had this once after moving the CT clamps to a different position, and accidentally putting them in the reverse order (due to the wires being hidden). After that mistake, all solar production was added to the grid consumption.
By the way. You are only sharing the Overview graph and not the Consumption, Solar and Grid data so it is a little gamble as to what exactly is going on.
Where have you installed the VM3?
CT1 at phase1 and in the VM3 port for phase1,
CT2 at p2 âŚ,
CT3 at p3 âŚ,
all CTs in correct direction,
all CTs fully clicked?
If its possible, post here a photo of the CTs/VM3.
The current VM3 firmware shows the âPhase Sequenceâ. Is it right? L1-L2-L3
VM3 is installed between the city meter and my first breaker. Before my ESS. On the blue X.
CTâs are fully closed and in the correct direction. L1 L2 L3 is correct.
See pics
One CT is in a wrong direction, at the gray cable. Or the other twoâs are wrongâŚ
If I see the details at the scond photo correctly (left L, right K), the brown and black CTs are in the wrong direction.
Yeah 
just what I expected.
By the way. That Hager switch is banned in Germany. Reason being that it can drop the neutral wire before the phasesâŚand then youâll and up with 400+Volts instead of 240V. Basically destroying everything that is connected 
Yes, i was thinking the same thing..
It looks wrong because the incoming gray wire is twisted in the other direction.
Not easy to get a good picture..
I tried to make a close up with every writing visible. All arrows are pointing towards the breaker.
Or am i mistaking?
I have put them in an other position now, after the breaker. Can you please confirm this is right?
see picture below
About the Hager switch.. I did not know this is not a good switch. Do you have any recommendations for a better one?
I donât want to 400v in my house 
Yes, thatâs why I thought one CT clamped wrong.
The CTs arrow shows INTO the house.
Open the gx GUI and go to the VM3 page. Take a large electrical load, hair dryer, water cooker or soâŚ, and connect this one into a plug at phase 1. Look in the gui, that L1 shows the load. Then the same procedure with L2 and L3. If all values are right, the CTs are correctly clamped.
The CT clamps have ânamesâ at a separate label CT1-HQ2⌠and so on.
CT1 at L1 and this into the L1 connection in the VM3? (If this is wrong, the measuring could be a little inaccurate.)
Look for âSontheimerâ or âKraus & Naimerâ on Amazon.nl (since youâre Dutch I guess).
And with the grid meter profile you should install the CT clamps before the switch on the wires coming in from the grid meter.
The âblue Xâ is the best/correct position, if TELLER at photo 1 is your LandisGyr energy grid meter.
A question to the VRM System Overview: Have you checked the other VRM graphs, Consumption and Grid?
How is your SMA inverter integrated to the gx?
to your 1. post
If the solar energy would be added to actual consumption, the consumption bar should be greater as the pure solar ennergy bar?
The SMA inverter is integrated via modbus into the gx. (sunspec)
After some more investigation, I think I found out what the problem is. I think the electrical installer (a friend) has made a mistake with the AC wiring.
Iâm looking into that with him right now, I will get back to you.
Holy â â â â .. You are totally right! I didnât see the CT1/CT2/CT3 written on the sideâŚ.
Apparently I have got some work this weekend⌠Iâll be back
I have readed that the CTs are fine calibrated in the factory process, matching the VM3 input ports for L1âŚL3. Only some 1..10 Watts will be incorrect.A little hint, cause you are now working in your system. 
Your CT wires are not very twisted. Your Photo 2.
âTo minimise induced noise, it is recommended to twist the wires like the wires supplied with the device.â
Page 4 in
So you will get better measure values.
And DOUBLE check the phase cables (numbers), also to the 3 MPs. The right order is important. Label the cables L1, L2, L3. 
About Hager bypass switch (omschakelaar): read the Victron pdf âwiring unlimitedâ page 56 section 6.6⌠here you need for each inverter/ charger two 2 pole switches⌠and.. no change for 400 volt on your 230v socket here, if the neutral isnât switched the inverter simply doesnât work.
Hager confirmed this issue per mail. Issue being. Iâm not joking! Neutral may switch off before the phases. In that case youâll end up with a floating neutral.
The idea is that the neutral wire must hold, until the phases are disconnected. After which the neutral should get disconnected. The other way around is to first connect the neutral wire, and then the phases.
Edit: Helmut over at @SchattenPV made a YouTube video about this. He also shows the letter from Häger. Hope this helps 
Hi - and many thanks for the lines above. I have very similar issues. The consumption adds loads in the house and what goes into the battery. Possibly I will just add another meter on ACout for the real consumption of the house. Thanks to the discussion above I also noticed the CTx writing on the stickers and I reordered them. Yet, the L1 coil still gives unreasonable data with a few watts, even if L1 ACin in the MP2 (in the device list in remote console) shows 2000W. Without the MP2-numbers is looks like a spontaneous generation of electrical energy ⌠The other two phases work well (actually even before I ordered them correctly). I may have thrown down the CT1 sensor initially and now need a tape to close it properly. It looks ok, but maybe it is somehow broken. Can one buy these sensors as spare parts?
The CTs snap lock sometimes is closed, the CT hold at the cable, but the snap lock is not closed 100%, sometimes the surfaces are not flat. This causes wrong power values. My experiences.
In the linked PDF above is written, the CTs can ordered as spare parts. (But if think about it, what is with the fine calibration?)
Keep an eye that the surfaces lying 100% flat and strong and no edges stands out. It could be difficult cause there is mostly not enough room to handle this.
If the power value differs so much, CT1 at L1 only some W vs. 2000W ACin MP2 at phase L1, the CT core or cables or something other is damaged; the CT1 port in the VM3?
(If I had this problem I would measure the internal resistance of CT1 and CT2 and CT3. They should have similar values. I hope the measurement do not destroys the CTs fine coil⌠)
Yes thatâs true for 3 phase+ N switches, but not irrelevant for the 1 phase+N bypass switches in the Victron pdf example.
But I donât know if you can savely bypass each Multi Plus one at the time with 3 separate bypass switches or not..
Thanks for the link. Shipping costs seem to be higher than the sensor itself, but ok. I actually already ordered another VM-3P75CT for the said ACout1 metering, then I can try with more sensors. Will the calibration be specific to each individual VM-3P75?
I just measured the resistance. It seems to be around 117Ohms for all sensors, no matter if the coil is clicked/seemingly-closed or open. If I understand the sensor correctly, this resistance should be that of the pickup wire wound around the closeable magnetic ring, which carries a magnetic flux induced by L1. Possibly, if the ring is not closed properly or the ring is even broken internally, the induced magnetic signal will be wrong although the pickup wire resistance is unchanged. I donât think I can measure the magnetic field well enough, but maybe this ring magnetism is delicate - and actually the reason for any calibration?
