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hglab avatar image
hglab asked

AC power meter "after" MultiPlus II possible?

Hi community!

In my setup the AC mower meter will be installed in the flat, the MultiPlus II in the garage. The power grid is splited in two streams. One for the garage and one for the flat. PVs are conncted to the stream in the flat. So it looks like:

ac-meter-install.png


Is it possible to configure the MultiPlus in a way that this setup is working? The MP should not target a 0 value on the meter but compensate the plus or minus on the meter by unloading/loading the battery.

Thanks for your support!

Multiplus-II
ac-meter-install.png (184.4 KiB)
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3 Answers
netrange avatar image
netrange answered ·

In this Case, you would load the Battery from the Public Grid ... and discharge the Battery back into the Public Grid ... With % loss ...

It would make sense , if you have a communication between the Solar Charger an the Multi ... to load the Batteries when PV Power is available

And the Meter is NOT after the Multi ...

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netrange avatar image netrange commented ·

I think , with the "normal" Victron Ability , this is not possible.

But if you use a GX Device like the Venus or a Raspberry "GX" , you cold use the NODE RED Option to create your own Options for carge and discharge the Batteries with the Communication between the Meter and the Multi II ...

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hglab avatar image hglab commented ·
Thanks for the reply! The PV Inverter is not compatible with the Multi and has no possibility to communicate to the Multi.

If the power meter shows a negative value, the multi could no to charge the battery and if it is positive to uncharge the battery. If this calculation would work in the Multi it should work at all, isn't it?

Would it be possible to add a second power meter in front of the Multi? Is the multi then able to add both meters and have an comprehensive view?

As I am living in an apartment house I cannot install the power meter before the the power-line is splited for my flat and garage.

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netrange avatar image netrange hglab commented ·

you have a small 2 PV Array Balkony Module with a 600 W Inverter on one Phase in your Apartment ?

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hglab avatar image hglab netrange commented ·

It's 900W (one phase) on the roof. But, you are right, it is a small one.

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netrange avatar image netrange hglab commented ·

The Communication between the 2 Parts of your Installation would be the challenge ... Maybe Powerbus from a Phase of your Apartment to your garage ...

Modbus RTU is not Possible ... You could use the Em24 Meter with Ethernet ... and a GX Device in your Garage ...

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hglab avatar image hglab netrange commented ·
EM24 Ethernet is installed in the flat and I have same Ethernet/WLAN in the garage, so that the Cerbo XC (is in the Garage together with the Multi) can be connected with the EM24. This should not be the issue
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netrange avatar image netrange hglab commented ·

The "0" feed in Option should not be the issue ... This is possible with the normal ESS option ...

The challenge is to load the batteries "ONLY" if the PV is available


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hglab avatar image hglab netrange commented ·

Can I add a second energy meter before the multi. Can the XC device work with two and sum it up?

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netrange avatar image netrange hglab commented ·
You can add different Em24 Meters ... as Power Meter on the Input ... and a "Solar Meter on the Output ...

BUT your Installation is a little bit different ...

The Multi would sending Power back to the Grid ... before the EM24 ... This Meter cant count the Curent comes from the Multi

Take a look into the Victron Installation Manuals .. There are different ways of Installatios ...

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hglab avatar image hglab netrange commented ·


If I put the second meter (also as power meter) like this, then I thought the multi should get the correct figures. The two meters are in total the same as one meter directly connected to the grid, isn't it?

1635013878698.png


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1635013878698.png (254.2 KiB)
netrange avatar image netrange hglab commented ·

... You damaged your Batterie ... get out of the Garage ... :O


This can´t work ...

The ApartmentMeter counts the Power from or to the Apartment

The GarageMeter the Power from or to the Multi

No of them worked as it should be...

As I say ... Possible ? YES ... BUT not the normal Victron Way

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hglab avatar image hglab netrange commented ·

sorry for all my questions!

Why is then this setup working? It is more or less the same?

1635015351088.png


What I thought why the to meters should work:

flat meter is measuring -200W
garage meter is measuring 10W (Mutli in standby)
GX calculates -190W --> Mulit loads battery with 190W
result:
flat meter: -200W
garage meter: +200W
GX: 0W
Multi is happy

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1635015351088.png (81.5 KiB)
shaneyake avatar image
shaneyake answered ·

Simple answer is no. The meter is intended to be installed on the grid supply.
If you install the meter on the grid supply it will keep the grid supply at 0W.
If you start pushing power to the grid the multi will take that power and charge the batteries.
The victron ESS system is expecting the Multi to be behind the meter so that the output of the multi and the loads cancel.

Is there a reason you don't want to put the meter on the grid supply?
You can have a second meter in the flat if you would like to monitor it's usage but not really for control.

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hglab avatar image hglab commented ·
Hi, I am not allowed to install it close to the grid, because this is in a common room.

And what about two meters? One in the electric box in the flat and the second in the electric box in the garage?

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shaneyake avatar image shaneyake hglab commented ·

Does the feed for the flat pass through the garage? Like where does the split happen?

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hglab avatar image hglab shaneyake commented ·
Unfortunately not; otherwise the solution would be easy. The feed comes into the electric room (where also official the grid power meter is placed). In this room the line is split. One for the garage and one for the flat.
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shaneyake avatar image shaneyake hglab commented ·
Okay, it is possible to get this system working.

You can use 2 meters or use the Multi as the garage meter and other meter in the flat.

You will need to install the large firmware on the Cerbo GX and run ESS in mode 3 but this is all possible will just need a bit more config.

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hglab avatar image hglab shaneyake commented ·

sounds complicated :-)

I think in this case I have to read throw a couple of additional documentation.

Are there any links/docs you could suggest? Steering Mode 3 via REST or MQTT is not possible? Only via ModbusTCP (where I have zero knowledge)?

I have a smarthome in place where I can listen the MQTT infos from the meter. So I could implement the rules there, if there is a way to steer the Cerbo GX via TCP/IP (Rest or MQTT)

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shaneyake avatar image shaneyake hglab commented ·
Do you have a Cerbo GX?

Where are you based?

Modbus TCP is really simple. If you can do REST I am very confident you can do Modbus. You can control Mode 3 via MQTT but it is a bit of a hassle to do the keep alive.

If you have a Cerbo GX, it is best to do all the control on the GX. NodeRed on the GX makes everything very simple, just a few mouse clicks and you will have your system up and running.

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netrange avatar image
netrange answered ·

Back to the Pad :(

The Current from the Multi , that is getting back to the Grid , HAVE to past the same Meter , that is getting the Current Information to the Multi ...

in your Picture ... The Garage Meter is only Measuring the Garage Power ... Nothing is happening on the Apartment Meter


...


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hglab avatar image hglab commented ·
ok, so two meters are not producing one view - then it is clear why it cannot work.

So it looks like I have to send all components back :-(

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netrange avatar image netrange hglab commented ·

Size of the Apartment ?

Option 2 ?


Multi and Battery in the Apartment ...

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hglab avatar image hglab netrange commented ·

There is storage room (close to the living room) where I could put it in. But not sure if the devices are silent enough to run there?

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netrange avatar image netrange hglab commented ·

The Noise of the Multi ... in some situations is very disturbing ...

But ... Try it ... Good luck ... From Germany


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hglab avatar image hglab netrange commented ·

very disturbing sounds not very optimistic!

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shaneyake avatar image shaneyake hglab commented ·
Would not recommend multi in living space, it is quite loud.

Also pushs out some serious heat.

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