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ty-web asked

AC Coupled Solar DUal Multiplus 2 in Parralel - Config Issues

I have 2 x 48/5000 M2's connected in Parallel sharing the load (both AC out 1 coupled together at SWB) this works fine. I have a Fronius 5000w AC coupled Solar inverter also on Out1. The M2's use frequency shifting to reduce the output of the Fronius when the batteries are full. All works perfectly for several months. NO grid connection - M2's not approved for grid in Australia.

Issue: I want to remove the Grid code and ESS as there is no grid, and I believe the ESS is limiting the DVCC functionality. When my JK-BMS completes the bulk phase and calls for float, it sets the M2 charge voltage and causes an alarm which triggers the high freq cut off of the solar on the M2, causing the loss of Solar production, unless I manual interfer, and turn off float mode in the BMS (Yes the New JK has float mode as well). Andy from Offgride Garage has this working correctly with one M2 and not using ESS.

However if I remove the Grid code and set it to none, remove the ESS assistant (in Both M2's) set the AC PV assistant up they restart in Parallel as before, but they dont allow the AC coupled solar to work. The PV initially tries to produce power, but with in 2 or 3 seconds something happens and it drops off and doesn't try again. I wasn't quick enough to notice if it ramped the Freq to 53 or if it was done via Modbus. I thought it might be the Cerbo GX causing the issues (ModBus), so I followed the process in the Manual and tried to reflash the Cerbo so I could start from a clean slate. However when it came back it still had all the same settings, I was running out of day light to test the Solar, so I ended up reversing the entire process back to As found.


My Only thoughts are there is something with parallelg two units and no grid code / or AC coupled only works if I use a hub or ESS? Not sure. Any suggestions would be apreciated, which hub 2/3 or 4 should I use if I have to go that route....I am thinkinh Hub 2. But think I should be able to get away without it at all.

Maybe its a parrallel thing and Ill have to seperate them in the configurator and try with just the master for now?

Multiplus-II
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4 Answers
Michelle Konzack avatar image
Michelle Konzack answered ·

If you are Off-the-Grid, WHY do you use ESS at all?


Disable ESS and you should be fine.

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ty-web answered ·

Yes Exactly my point. I am trying to do away with ESS, but the Multipus 2 in parallel dont seem to want to work with the AC coupled PV. I am trying to find out if other have had the issue and how they got around it.

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JohnC avatar image
JohnC answered ·

@Ty_Web

You've seen this?.. https://www.victronenergy.com/live/ac_coupling:fronius

The PV Inverter Support assistant is likely your best start point.

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ty-web answered ·

Thanks John, I have seen and used this doco to set it up initially and its been working great with the ESS assistant since install in August. However, when I try to remove the AU grid code and the ESS assistant, and just use the AC PV assistant as per this doco you ref it hasn't worked so I have just lived with the ESS assistant.

I had a couple days off up my sleeve this week and I wanted to attempt to fix the issue doing away with the ESS assistant as I have no grid connection....but I cant get the Fronius to provide power and keep doing so. The system kicks it off the bus and the Fronius goes to idle zero output.

I think I will try separating the two M2's (not Parallel) and see if I can make it work with the master M2 only and see if this narrows down the issue to the Cerbo or the M2 in Parallel.

Cheers for the link.

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JohnC avatar image JohnC ♦ commented ·
@Ty_Web

I don't know how familiar your are with this stuff, so forgive me reiterating what you may already know well.

The ESS Assistant is installed in the Multi, even though you may control it from the GX. The PV Inverter Assistant needs to be installed in the Multi too. Deletion/Installation is done there.

I don't think Victron Connect can deal with Assistants, so you'll need VE.Configure to do this. Either via VRM or MK3 adaptor. The Victron website for the software and manual(s).

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