How to configure one phase Multiplus II in VRM to use phase L3 instead of L1

DIY
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Hi there, please can someone help.

I have a one phase system with a Multiplus II 5000 and a RPI running the Venus OS 3.5. For symplicity reasons I have connected the Multiplus to L3. Now I have observed that the calculations regarding the critical loads are wrong. I measured the consumption of the connected critical loads manually and they are roughly 70-80W but the VRM shows 151W. After some thinking and calculations I have discovered why the consumption on the critical loads is shown incorrectly. The system assumes that the Multiplus is connected to L1 and also calculates the consumption of the critical loads taking L1 as base. But in a three phase system there is a 120° phase shift between L1 and L3 and if not mistaken then cos (120°) is 0.5. This is the reason why the critical load is shown twice as high as it actually should be.

Can you please help. Is it possible to specify somewhere that the Multiplus II 5000 is connected to L3 instead of L1. I believe this should correct the miscalculation. Thanks a lot.

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The master is always assumed as L1.

It should be measuring its output but generally can get a bit inaccurate with smaller currents.

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@LX, thanks a lot for the answer.

I updated the above picture to show where the data is comming from. Is there really no way to change the settings somewhere that AC-Input 1 is connected to L3 ? I can’t be the first one that has observed this.

BTW with high loads it get’s even stranger :frowning:
I connected a hair dryer (see picture) and it seems as if my system magically generates energy because the input power is 1865W and the AC loads use 2898W and no, the battery is not contributing

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4

If you have a grid meter swap L1 and L3 on that, now the systems thinks its on L1 while on L3

5

Important: When installing a single-phase ESS in a system with a three-phase connection to the utility grid, make sure you install the ESS on phase one, L1.

https://www.victronenergy.com/media/pg/Energy_Storage_System/en/installation.html

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6

If you have a grid meter swap L1 and L3 on that, now the systems thinks its on L1 while on L3

@Marc, Good idea, I changed L3 to L1 in the RPI plugins for the Shelly although I would have preferred not to do it.

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Important: When installing a single-phase ESS in a system with a three-phase connection to the utility grid, make sure you install the ESS on phase one, L1.

@M_Lange, Okay I have seen the note in the document, but is there a “real” technical reason for it ? I cannot see any at the moment. When I run a three phase motor then L1, L2 and L3 need to be connected in the right order but for single phase system I cannot think of a reason. Apart from avoiding problems like I have described it.

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I think, in your case, You can put the critical loads (single phase multiplus) on real L1 only.

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Just a heads up you cant use an et112 or any other single phase victron meter to messure any current on L2 or L3

You need a 3F meter to mesure single phase loads

Greetings from " the same dev team that made you switch your L1 and L3 "