This site is now in read-only archive mode. Please move all discussion, and create a new account at the new Victron Community site.
On the multiplus II there is a current sense port. I can't find how to use it.
In the online training I see the current sensor is connected to the temperature sensor or the aux ports an that is also what the ac assistant is giving as options.
How to I use the current sense port ? I have a sct013 100A 50mA current sensor from my own energy monitoring project also from yhdc as the one victron uses. Would like to reuse that sensor.
Who can help me read that value ?
You have looked at the Datasheet?
Current Transformer 100A:50mA for MultiPlus-II / MultiGrid-II to implement PowerControl and PowerAssist and to optimize self-consumption with external current sensing. See MultiPlus-II datasheet for more details.
Current transformer. <<Link
Hi there,
This thread has helped a little bit but I still need a clarification to ejrossouw 's comment.
If I have a PV inverter + grid on the AC-in port, and I wish to see logical data for the Grid values (and Loads). The plan is to use ESS to set up self consumption and see correct data.
1) Should I connect the CT to the Grid main feed of the house
2) Connect the CT before the loads paralleling everything on Grid side?
Number 1 option makes sense to me. However then I cannot see a way to read the paralleling loads. (Unless its calculated?)
Many thanks in advance!
Also in my case I am able to read the PV production via PV inverter (SMA) sending the data using the Modbus TCP server (which the cerbo is able to read). See third picture below.
Please see the image:
VRM:
The CT is connected as per 1 and shown in the ESS manual, just using an ET112 as opposed to CT. You will require a GX device in order to use ESS.
Thank you for the reply @ejrossouw
I have a Cerbo GX in the installation.
There is still not perfect / clear documentation on this ESS implementation and wiring released by Victron (IMHO).
The words used by people in this thread are somewhat vague, others have mentioned words "current sensor" - which logically could be a CT (but following links say it is not).
Industry definitions for "Smartmeter/energy meter (normally measuring Volt,Amp, Watt)" is different to a "current sensor/current transformer (only measuring amps)".
The Victron "current sensor" product is only made to measure PV Inverter power connected to the AC input or output of a Multi or Quattro. They should have named the product Victron PV sensor or Victron PV smartmeter (because the output is digital output).
Then the actual "current transformer" product is only made to measure grid input to premises to avoid grid-feed in - According to multiplus 2 datasheet. They should have named this product Victron Grid Sensor or Victron Grid CT (because the output is analog output). This product or feature SHOULD ideally be able to do what a smartmeter/energy meter does on the grid input side, yet it does not. Why?
So, using a CT (current transformer such as the blue YHDC) plugged into the current sense INT and COM ports will not be sufficient for ESS? The links I posted have contradicting info. Multiplus 2 datasheet says the CT is to optimise self-consumption and, if required, to prevent grid feed.
A smartmeter will output digital output via rs485/VECan and must be connected to the GX. The installation of a smartmeter/energymeter like the ET112 (shunt) is very intrusive and not easy for all customers. Installing a CT is much easier.
I do not want to install the ET112 unless I need it for ESS. I read then this in the ESS documentation :
Grid Meter (optional)
An Energy Meter can be installed in the main distribution panel between the grid and the installation for a full or partial grid-parallel installation.
A grid meter is not required where there is no AC renewable-energy source(s) and also no AC load(s) present on the input side of the Multi/Quattro system (i.e. where all such sources and loads are on the output side of the Multi/Quattro system).
If there is any AC renewable energy source or any AC load between the grid connection point and the input side of the Multi/Quattro system, incorrect results will be calculated and recorded by the GX unless a grid meter is installed and enabled.
In particular, without a grid meter:
• When renewable energy is being provided on the input side, the grid value will be wrong (too low/negative); and Comment-- BUT if we use TCP Modbus server or current sensor then the PV production would be known!
• The AC Load value shown will be too low (and will show zero where there is a surplus of renewable energy).
Both issues are resolved by installing a grid meter.
Also having to find software setting definitions from community pages is not ideal, eg like this or this.
@cooleco The CT is an extension of the MP-II's internal metering and can be used for ESS as I already pointed out. (It has a dedicated port.) You can otherwise use an "external" ET112 energy meter. The choice is yours. If your PV inverter cannot communicate with the Cerbo and you want to diplay it's production, you can install an additional ET112 or even ET340 as below. 
Typically these points are discussed with your dealer who should be able to answer your questions at the system design stage. Victron systems are typically installed by qualified professionals and while documentation is comprehensive, it is not intended as in-depth training/installation material on products.
Thank you @ejrossouw
We may test out the CT solution as it is easier to implement.
Do you have any reference to documentation or any links to share that says the current transformer is OK for ESS?
Only document I found was the Multiplus 2 datasheet:
https://www.victronenergy.com/upload/documents/Datasheet-MultiPlus-II-inverter-charger-EN.pdf
Cheers
It is the value shown for the MP in VE.Config, VE.bus monitor, rconsole and in the VRM portal. Not sure what else you expect. Underlined in red.
The shunt gives you DC view, while CT an AC. It very much allows the MP to see AC loads "in front" of it when connected grid parallel to e.g. household loads that is not connected to ACOUT. If there are no loads parallel to the MP it will not add much value as the MP already measures what passes through it.
In your last post this looks to be what I want but where do I see that value when I connect the current sensor.
In my situation the multiplus is not AC IN connected so is that maybe an issue ?
My apologies. My screenshots were wrongly showing the battery value. The CT value is in the grid box.
Feel the need is to read up on the excellent victron manuals and to grasp the basics.
External sensor 3.5mm jack socket simply disconnects (when you plug an external ct into it)the MP internal CT clamp ( measuring AC current passing through the MP) and transfers the measurement point to where ever you place the CT clamp, this is displayed as Grid /shore or whichever you set the MP as.
For ESS the point at which you place the CT is usually grid supply coming into the system, then set grid set point( amount of electricity you wish to flow into system from grid ) and ESS will then try to maintain this set point (subject to many other set- able parameters).
Really this is another question, but fits with this thread.
If you have nothing else connected to grid, that is batteries and PV all power the 48VDC bus directly, then there is no need for a CT at all as the Multi-2/Quattro-2 will automatically disconnect on mains failure.
PS All loads are on UPS line. Exporting surplus PV to grid is however an aim.
HTH
