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energy-z asked

ESS system with two signal BMS and a SMA inverter

Hi,


I have a system installed with:

- One grid inverter [SMA Tripower (STP) 20kW + SMA Home manager 2.0];

- Three multiplus II (3kW, each);

- And a 3.7 kWh battery made of eletric vehicle modules with a BMS with two signal;

- One carlo gavazzi meter ( EM24DINAV53DISX );

- I'm using ESS with two signal BMS control;



The 20kW SMA is setup for zero injection on the grid (self-consumption), but sometimes it does feed power back to the grid since the three fase loads vary in time.


I have 4 questions:

(1) - The multiplus II is not delivering power back to the loads when they need that power (i.e. when there is not enough sun and the battery has 100% SOC), how can I comand the inverters to pull the energy from the batteries and delivered back to the loads? I'm trying to avoid at all costs to inject power back to the grid.

(2) - I have a Venus GX + warning LEDs installed in the DC bus bar of the battery, this loads are pulling energy from the battery and voltage keeps following. The Remote console and the other graphs shows the SOC at 100%, but I know that it's not real, since for my battery 64V is 100% SOC and 52V is 0%, how can I control the SOC and display the correct SOC values?

(3) - I want to charge the battery with all the inverters installed in all three phases, but when I was configuring the assistant, he only offered me the possibility to have one comand to the battery BMS, how can I do this? I have already three relays for each inverter, but right now I'm using only one input.

(4) - I want to store the excess of eletricity in the phases that are unballanced, how can I do this? I can see in the tab (advanced) at VRM what are the phases, that are unballanced but I'm not able to pull that energy into the DC bus bar back to the battery or back into one of the other phases. I know that this is not the most efficient system, and that, I'll lose energy in this process, but I need that configuration.


I've already read many articles in the Victron Live web page, but didn't found the things that I was looking for, here are some examples:

https://www.victronenergy.com/live/ess:design-installation-manual

https://www.victronenergy.com/live/ess:quick-installation-guide

Etc;


Thanks for your attention and feel free to ask me another questions.


Have a nice week,

José.

Multiplus-IIVRMBMSVenus GX - VGX
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boekel avatar image boekel ♦ commented ·

You might want to read this also:

https://www.victronenergy.com/live/energy-meters:start?

https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems

some remarks:
-your battery is -very- small for this system
-the diagram you posted is not your system, can you tell where the SMA is connected?
-you have an SMA manager, how did you set this up to let them work together with the Victron system?

https://www.victronenergy.com/live/ccgx:ccgx_sma

your questions:
1) what ESS mode are you using?
2) how did you setup the battery monitor in the multi's?
3) https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems
4) turn off 'phase compensation'

Please have your system checked out with your distributor / a victron installer, all your questions are basic knowledge for installers and if you don't get the settings correct you can have very dangerous situations.

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energy-z avatar image energy-z boekel ♦ commented ·

Hi,


Answering your questions:

"

some remarks:
-your battery is -very- small for this system

[Jose] (Answer): Ok, but it worked with some tests and it dellivered charge quite nicely.


-the diagram you posted is not your system, can you tell where the SMA is connected?

[Jose] (Answer): The SMA inverter is installed at the top near the rectangle (in the image bellow) that says "LOADS".


-you have an SMA manager, how did you set this up to let them work together with the Victron system?

[Jose] (Answer): The SMA is connected to the home manager, and the home manager controls the inverter. The carlo gavazzi meter monitors the energy flow at the installation, he detects when there is flow energy from the grid to the installation and vice versa.


https://www.victronenergy.com/live/ccgx:ccgx_sma

your questions:
1) what ESS mode are you using?

[Jose] (Answer): Only ESS. They are configured in all the inverter and in the VRM.


2) how did you setup the battery monitor in the multi's?

[Jose] (Answer): I didn't understand your question. Are you talking about elletrical connections is that it?


3) https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems

4) turn off 'phase compensation'

[Jose] (Answer): I did, but it didn't changed anything...

Please have your system checked out with your distributor / a victron installer, all your questions are basic knowledge for installers and if you don't get the settings correct you can have very dangerous situations.

[Jose] (Answer): I'm in contact with them, but they attend multiple costumers and the waiting list is too long. That's why I decided to investigate, ask in the forum, and read as many information as I found.

"

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boekel avatar image boekel ♦ energy-z commented ·

It's good to get to know your system, but please have this complicated system setup correctly by a professional.

you have an SMA manager trying to get to 0 feed-in, and Victron ESS system trying the same thing, how have you set this up to work together?

please re-read this as it answers most of your questions:
https://www.victronenergy.com/live/ess:design-installation-manual

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energy-z avatar image energy-z boekel ♦ commented ·

Hi, once again.

It was setup properlly (by me and my team). The issue is that this is the first time that this has been done and it's normal that we ran into problems.

The SMA gets 0 feed-in.

The victron system has the main goal to absorb the energy flowing from the pv plant to the grid, that's the main objective that we are aiming at.

The system has two parts:

(1) - SMA inverter + SMA home manager, setup to 0 feed-in;

(2) - Victron inverter + battery (two signal BMS) + 3 phase carlo gavazzi meter;

Note:

The two systems are independent and they are not comunicating with one another.

For example in this image bellow, I would like that the L2 and L3 power where flowing back to the battery instead of flowing to the grid:

If we manage to solve this issue with this system I'll tell you, how we manage this issues.

If you have any sugestions, please tell. Any help that I can get is welcome :)

I'll read the ESS manual once again

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boekel avatar image boekel ♦ energy-z commented ·

quote:

The SMA gets 0 feed-in.
The victron system has the main goal to absorb the energy flowing from the pv plant to the grid, that's the main objective that we are aiming at.
The system has two parts:
(1) - SMA inverter + SMA home manager, setup to 0 feed-in;
(2) - Victron inverter + battery (two signal BMS) + 3 phase carlo gavazzi meter;
Note:
The two systems are independent and they are not comunicating with one another.

How can the Victron system know when to charge the batteries when the SMA system is set for zero feed-in?

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energy-z avatar image energy-z boekel ♦ commented ·

I'm hoping that the carlo gavazzi works with the victron platform to tell the inverters to charge, since it can detect when the energy is flowing back to the grid (as shown in the image bellow).

The zero feed-in, is fact "near zero". Why is that? Because, it's very difficult to consume the same, in all 3 phases, at the same time.

The zero feed-in for SMA, works this, way:

Consumption:

L1: 2.000W

L2: 3.000W

L3: 4.000W

Total: 9.000W


Production:

L1: 3.000W

L2: 3.000W

L3: 3.000W

Total: 9.000W


This way, the load ballancing is:

L1: -1.000W (power flowing from the installation to the grid)

L2: 0W

L3: 1.000W (power coming from the grid to the installation)



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boekel avatar image boekel ♦ energy-z commented ·

Yes, the SMA is doing this, so how can the Victron system know there is a surplus?

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energy-z avatar image energy-z boekel ♦ commented ·

The carlo gavazzi meter provides the data to the venus GX.

The image bellow, shows that:

My supplier told me that, it was possible to take power from those phases (L2 and L3) that were exporting power to the grid and store them in the battery. But since he has to gave assistance to all his clients in the iberian penisula (Portugal + Spain) is taking him a eternity to answer my e-mails and provide assistance via team viewer.

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1 Answer
laurentiupitran avatar image
laurentiupitran answered ·

hello,

just for information regarding loss of power back in the grid, even injection is set to zero.

this picture is from my system , ESS also, three phase.

finally, every day i use around 1,5 Kw from grid due to the ESS system and i inject near same; please take attention to the positive part of graph that is used from grid and negative part , that is injected on the grid - without my choice.


laurentiu


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energy-z avatar image energy-z commented ·

I, thanks for your answer.

I'll try to minize the feed-in power, but it's possible till some point...

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