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snaptec asked

Multiplus II GX ModbusTCP reading problems

Multiplus II GX connected to Liion Battery. ESS activated. Only AC-IN connected, no AC-Out

When ESS in "optimized" I can set the grid point with register 2700 on ID 100.


When setting ess to "external control" (aka Mode 3?) the Multiplus goes into ESS passthru.

On top of that ID 242 / 246 is not readable (registers 37/38/39).

They are also not readable in optimized mode and also tried reading them with ID 100. No chance.

I can write to them, but nothing happens.


Multiplus-IIESSgx device
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Alistair Warburton avatar image Alistair Warburton commented ·

I have been looking at simmilar stuff recently because I want to manage my generator with a PLC and hook the entire system to a HA system I am working on.

I am off grid so no ESS in play and may battery is BYD so no relavent experience but I did note that when my kit is in 'external control' it is because the BYD is driving its parameters.

I cant help wondering if the lack of responce to a control register, that you are seeing, is because something else has, or should have, control at that point.

I found the documentation frustrating, not because things dont work but because I cant find how or why they do.

Case in point... Untill my battery got cold the other day I didnt know if the chrge current on the MPPT would get modified as per BYD spec. It did and the portal reported that but I couldnt see it locally! I suspect there is an internal register, that the BMS drives, that the MPPT uses when in external control.

I havent found a single document describing what is governed by what else, in a given configuration or circumstance. it works but generally I dont know why or how.

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snaptec avatar image
snaptec answered ·

No one?

Victron says: " Talk to your dealer", Dealer says: "Handing that out to our techs", no reaction.

Multiplus mounted and not useable.

Feeling a bit lost, is my use case that exotic?

Side question:

Regarding the TCP Register, Register 301/302 (charged & discharged energy) is not readable.

Which modbusID to use?

Is it possible to get the charged & discharged energy from AC in?

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snaptec avatar image snaptec commented ·

Got an answer from Victron itself.

In v2.34 it is not possible with the gx.

Upcoming in 2.4

https://community.victronenergy.com/questions/31299/venus-os-v24034-available-for-testing.html

Questions regarding register 301/302 are still uncleared.

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michelp avatar image michelp snaptec commented ·

I have Multiplus-II gx in ESS mode 3 running fine, but one thing appends before that the VEbus Id change from 242 to 228


I dont'nt know why but it's.

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