Multiplus II ESS inverting issues.

DIY
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1

Hello,

I recently installed a MultiPlus-II 48V 3kVA unit to replace my trusty Sun Grid-Tie inverters :). Before this upgrade, I was running multiple Sun GT inverters on both legs of my system.

My setup:

  • 48V battery system
  • Victron Charge Controllers
  • Cerbo GX
  • Victron Shunt
  • Remaining Sun GT inverters still active on the other leg
  • CT sensor installed for the new Multi.
  • Multi connected to the grid via a 30A breaker on the AC-IN port

My goal:
I’m located in the U.S. and cannot export to the grid. I want to use the ESS function to import just 10–20W (even with full battery) and self-consume as much as possible from solar and battery. I fully expect to import power when needed, as I’ll never produce enough solar to be off-grid.

Issue:
The Multi is only inverting around 4W, and the system shows the grid as “Disconnected” in the GX system. My battery has plenty of capacity, so I expected it to be inverting more. I’ve set the Multi to “Inverter Only” mode. I’ve read a lot of documentation and forum posts, but I still can’t figure out what I’m missing.

In the GX screenshot, the DC Loads represent the Sun GT inverters operating on the other leg.

Can anyone help point me in the right direction?

Thanks in advance!

Pecan-VRM-Portal-07-12-2025_09_43_PM
Pecan-VRM-Portal-07-12-2025_09_43_PM1552×920 116 KB

2

How have you configured the system?

3

Hello Nick. I’m attaching all the settings pages from the VEConfigure, except the advanced page which unchecked. The ESS pages are mostly default, just changed the battery type to LifePo4.

Thank you.

Assistants tab
Assistants tab785×596 59.7 KB

Charger tab
Charger tab780×578 78.6 KB

General tab
General tab772×580 102 KB

Grid Tab
Grid Tab781×592 59.4 KB

Inverter tab
Inverter tab787×577 100 KB

4

I tried a couple of different CTs, which are not Victron but now I’m wondering if Victron CTs are very special… Those CTs that I used are 100a, 50ma, same rating as Victron’s.

5

Ok, I think I found my problem, I changed the Multi setting from “Inverting” to “on” now, it’s properly displaying and inverting battery power to AC. I thought it should be “inverting” since, i don’t want to charge my batteries from the AC.
Another thing, even though I set the grid point 40W, it fluctuates to export a few watts from time to time, I might need to set it higher. Do i need to worry about the code ESS #6?

Screenshot 2025-07-13 171334
Screenshot 2025-07-13 1713341421×826 86.6 KB

6

I have ESS#6 most of the time. It just means I have set the charge current to 0. I use DVCC to set it 0 I dont know where you could have it set to 0. Maybe you have overruled in remote?

ESS #6
User configured a charge limit of zero

7

So many setting combinations. :slight_smile: still going through the system and try to understand each option. Thanks for sharing the ESS #6 code.