2 X Multiplus 2 in Parallel not charging correctly. ESS

[RedGU]

I have an issue.

Running ESS.

I had a single 48/3000 multiplus 2 and this would work great. It would maintain the 50w on the grid and try to put all of the grid connected PV towards battery charging.

I had excess PV due to the limitations of the multiplus 2 charging at its max.

So to increase the charging capacity to try and use all the grid connected PV and export as little as possible, I got another 48/3000 MP2.

They are setup in parallel, with identical AC lengths and identical DC lengths etc.

But it now looks like the MP2’s are not evenly trying to charge the battery. I am actually now exporting more to the grid than I was originally, and the batteries and not being recovered.

I have 2 x ET112 meters, one on “Grid Metering” and one on the “Grid connected PV”.

I also have an external Victron CT (CTR12) to monitor loads.

To me it looks like:

The MP2’s are trying to share the charging, but only 1 is actually charging (so only using half the available Grid Connect Solar). I need to be home during the day to put a clamp meter on the DC side of the inverter.

I have nothing limited in the charging or inverting and no DVCC set up.

I have tried DESS On and Off, in Green mode ETC, and no difference.

Screenshot_20250903_103130_Chrome1080×2121 155 KB

image775×131 4.34 KB

1 x 48/3000/35-32 GX

1 x 48/3000/35-32

Just to add another weird issue.

If i set the Grid Current Limit to 16A, for example, the max I can draw from the grid is ~8A. This is doing the exact opposite to what i thought 2 in Parallel is meant to do. (3A on 6A, 5A on 10A, ~6A on 13A, 16A on 32A setting ETC)

Anyone seen this? Could it be a firmware bug.

It is running the latest official release.

Also i have seen conflicting information on what you do with the current sense of the slave unit do you have it connected or just remove it completely?

Cheers.

Red.

[owenb79 (Owen)]

I haven’t had a parallel system for a while. On the charger side, make sure you’ve set the max charge current to 70 A in VEConfigure 3, since that setting is for the entire parallel setup, not per Multi.

[RedGU]

Unfortuantly it wont let me choose 70A. 35A is Max.

[owenb79 (Owen)]

I may have remembered wrong.

[nickdb (Nick)]

The setting is per multi. The only global settings are in the GX or VRM.

[nickdb (Nick)]

These are global settings. 16A would be 8A per system, if you are only seeing 8, it sounds like one is not connected or is misconfigured.

The Current sensor is only required on the phase master.

[M_Lange (Matthias Lange - DE)]

What battery do you have?

Did you configured the ESS assistant on both MultiPlus?
(“Send to all devices” does NOT work for assistants!)

[owenb79 (Owen)]

Did you right-click the master to get into VEConfigure after setting them up with VE.Bus? Also did you set the AC in current to be able to adjust it with remote?

[RedGU]

Hi Nick.

I have 20kwh’s in 4 x 5kwh strings.

And yes to the assistant on both MPs.

[RedGU]

Hi Owen.

I did have that selected. It’s a weird one.

[RedGU]

I found this in a Victron document.

I have never disconnected the GX device that’s In the 48/3000/35-32-GX before programming.

ve_online_-_multi_and_quattro_parallel_and_3_phase.pdf https://share.google/0PfwY9Hr0CeXQvLQs

Does this have to be done?

Cheers.

Red.

[ldaelettroimpianti]

I hadn’t done it either, so I reconfigured everything with the GX disconnected but nothing changed

[Sean]

Can you post a schematic to illustrate exactly how you have wired your system up, specifically the metering devices, including the CT.

[RedGU]

Hi Sean.

My system diagram.

Cheers.

Red..

[Cas446]

The location of the CT could be causing issues. How is it configured? Try removing it, so that the grid meter is definitely used.

[RedGU]

I have tries almost every combination.

If I remove the CT, it seems to do nothing and does not follow the grid meter.

I will remove it again and see what the result is.

These are my ESS settings:

[Cas446]

“If I remove the CT, it seems to do nothing and does not follow the grid meter.”

What you have written would suggest that your grid meter is not configured fully, although this could just be my interpretation of your wording.

Suggest you turn the grid pv off, remove the pv meter and CT, leaving just the grid meter. Apply a fixed load (hairdryer), and check both MPs are load sharing. Then invert the grid meter CT and check both MPs are charging. This is the baseline to prove the parallel configuration and removes metering config issues. If this doesn’t work, then at least you know it’s a parallel config issue.

[Sean]

Where/how have you configured the CT ?

Given you have grid metering in place a separate CT isn’t required, as per the previous comment you need to confirm what device is doing what.

In a grid parallel ESS, that has a energy meter the CT is redundant.

[Mysik]

You’ve mentioned that you have two ET112 meters… make sure that the correct one has been set as “Grid meter”, also your ESS setting for grid metering is “External meter” so you need to unplug CT clamp.

[RedGU]

Hi Sean.

I am aware that the CT is not required when you have grid metering as per the design / installation documents but at this stage, it’s the only way i can get it to work properly.

I have just done some tests with the external CT connected, Internal CT connected and having the CT (Internal and external) disconnected completly.

These are the results:

This is with the external CT connected: (and the ESS function is working as it should)

Internal CT Selected: (ESS function stopped)

No CTs connected (plug removed - ESS function stopped)

I have it set to have the MP know the loads are on the Input and Output:

Looking at the results, it appears that this settings is not being followed:

And is only covering critical loads.

That explains why the system performs normally when the CT is placed where it is measuring all the loads, making the system think they are all “Critical”.

I will remove the CT from the system and do a reboot, and then even reset it back to factory settings and try again.

Cheers.

Red.