How to configure Multi-Plus II to charge battery from AC side PV

Q&A and troubleshooting
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1

Hi all,

sounds like a simple question, but I just don’t find it…

My system consisted originally of victron setup of DC side PV, cerbo gx, Multi-Plus 2, pylontech batteries and EM24 grid meter. (Installed in 2023, last firmware update about 1 year ago.)

Things have been configured to prioritize maximum direct consumption, charging batteries and feeding the leftovers into the grid, i.e., ESS control loop setpoint set to 0.

We now got ourselves an extension on our garage. The electrician had recommended Huawei for this (I don’t recall why) and connected it AC side but still inside the EM24 such that I can see the generated power in the victron app as outgoing power. (The Multi-Plus is on phase L1, this extension is on phase L2.) The setup now basically looks like this image that I stole from a similar post that I found now, except that the Multi-Plus and the extension PV are on different phases:

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I should mention that the Huawei PV inverter is not explicitly known to the Victron system. It only observes via the EM24 that there is at times a negative flow of energy on L2.

Currently, I observe the following behaviour that I am not perfectly happy with: when the extension produces power and more power is consumed in the house than produced by the extension, the victron system balances things nicely including the power from the extension. But if there is lower demand for power in our house, then the extension’s power is not used to charge the batteries but whatever is not immediately consumed is fed straight into the grid.

I see many posts here, where people have systems charging their batteries from the grid based on variable-rate electric contracts, so it seems well within what can be configured, but I just don’t find it.

Could anyone please share insights on parameters or approaches to get this done, be it a switch to flip in the config or anything to do in node red?

Thanks a lot in advance.

2

Hi you will need to set it up as ess and you will need a extra energy meter connected to your pv inverter to do what you want

3

Thanks for considering my case.

I have also read this “another energy meter” in other similar posts, but just don’t get it. Why would I need that / what would I do with that?

4

With an energy meter on the pv inverter the victron system can see the power it generates and can calculate with that

right now it cant and doesnt know where the negative energy on the grid meter comes from and calculation will be wrong

5

the solar panels are just shown in the Victron overview

nice to have, but has nothing to do with ESS - ESS will work like before

6

As @DuivertNL said you need another meter, one actually on the AC output of the solar inverter, in addition to the grid one. On my two arrays I have an ET112 on both of my solar inverter arrays.

7

maybe this helps:

8

Thats true, but it will also be used in all calculations

9

Thanks all. Especially the thing with proper integration via the code on GitHub sounds nice…. if the connection can also be established via Ethernet connection through my home network and Ethernet dongle in the Huawei inverter.

I still wonder though, why it should not be possible for the Victron to work with the available info. It would be all there … clearly visible that in this example 669W are going out on L2 which could be compensated by the Multi-Plus on L1.

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