question

brent1982 avatar image
brent1982 asked

DMC needed with Cerbo GX, Gx Touch 50 with Multiplus 12/2000???

As the title says, everytime i chop and change my equipment selections for my upcoming RV build, im presented with more confusing aspects.


Do i need the DMC with the above mentioned components if im using a VE.Bus BMS or has that been removed now? Can i control the Charger only/On/Off portions with the GX Touch 50 or will i be required to install another component, that being the DMC???


System will also have MPPT, smartshunt, 2/3 x lifepo4, smart battery protect

MultiPlus Quattro Inverter Chargercerbo gxgx deviceVE.BusDigital Multi Control
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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Currently it is not possible to remotely switch the Multi using a GX device when a VE.Bus BMS is installed. Instead of the DMC you also could use the VE.Bus smart Dongle to control the Multi using the VictronConnect app.

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brent1982 avatar image
brent1982 answered ·

@Matthias Lange - DE Will that work if I still have the VE.Bus BMS installed in the system? One VE.Bus port on the Multiplus would go to the Smart dongle, and the other VE.Bus port would go to the BMS?

I think im getting confused looking at some of the Victron Schematics that incorporate lithium batteries, ve.bus bms, multiplus and the CCGX.

Do i need to control the voltage or the charger only/on/off on the inverter? The inverter will be used as the charger, and then ofcourse an inverter when im not connected to mains power.

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bathnm avatar image bathnm commented ·

@Brent1982, I can't comment on the VE Bus Smart Dongle as I do not have one. If you want to control the Multiplus from the Cerbo, you can always wire the Charge Disconnect and Load Disconnect into the Aux Ports, and then use the 2 Wire BMS assistant on the Multiplus rather than VE.Bus Assistant. I tested this last night as I too am frustrated at the lack of support for VE.Bus BMS and Cerbo, and just do not have space to install a DMC.

If the VE.Bus Smart Dongle will control the MultiPlus then I have no idea why the Cerbo can't !

@Matthias Lange - DE, Could we at least get some direction from Victron if this will ever be addressed, as in it is just a software issue or is it broader than that and will never get addressed.

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brent1982 avatar image brent1982 bathnm commented ·

@Bathnm i know what you mean. As great as victron gear is, its very annoying to need multiple different components to do very similar things.

Im still no closer to understanding if i can use the ve.bus BMS and the ve.bus smart dongle in the same install and still control the settings of the multi. Or if i even need to control them. Was pretty much after a set and forget system and just have monitoring. And know that if i do go offgrid, the inverter will do what i need it to do when i need it to do it.

Maybe im just over thinking it all and over complicating it. It is only a caravan after all. And i will only have the need to use a couple of AC appliances occasionally whilst offgrid and maybe a little bit of Air conditioning. Otherwise most things will be 12v DC

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·

@Brent1982 The BMS and the Cerbo GX are connected directly to the Multi and the DMC/VE.Bus Smart dongle will be connected to the BMS' remote port.

@Bathnm If I remember correctly I saw somewhere a comment that Victron is working on a solution, but I can't find it anymore.

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bathnm avatar image bathnm Matthias Lange - DE ♦ commented ·

Hi @Matthias Lange - DE, Do you mean this port that is circled.I keep hearing that there was a comment, but none can provide any details.

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brent1982 avatar image brent1982 bathnm commented ·

@Bathnm Victron Australia, and in essence one of their resellers, have confirmed i do not require the DMC. The system can be installed as per schematic. https://www.victronenergy.com.au/upload/documents/VE-Bus-BMS-example-with-3KW-12V-MultiPlus-230-Volt-revision-B.pdf (with the CCGX being replaced by the cerbo/gx touch)

And with this, the cerbo gx/gx touch 50 will control that and also control DVCC. So the system seems to have been a little more simplified now which makes it easier for all of us.

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bathnm avatar image bathnm brent1982 commented ·

Maybe I'll do some testing when I am next on the boat. It would be great if manuals and information could be updated or better distributed to people. From hat I have read and seen this change in connection of the Cerbo to the Remote Control port, will always have been possible as no firmware updates have released that change any behaviour here.

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Justin Cook - Bay Marine Supply USA avatar image Justin Cook - Bay Marine Supply USA ♦ brent1982 commented ·

@Bathnm, @Brent1982

Hi all,

For the record, that schematic as linked is incorrect.

The GX device connects directly to one of the Multi/Quattro's VE.Bus ports.
The BMS connects to the other VE.Bus port of the Multi/Quattro (possibly through the AC Mains Detector, depending on your model of Multi/Quattro).

Switching the Multi/Quattro's state through the GX device is not possible when a VE.Bus BMS is present, thus the requirement to use a DMC connected to the "remote" port of the VE.Bus BMS.

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bathnm avatar image bathnm Justin Cook - Bay Marine Supply USA ♦ commented ·

@Justin Cook - Bay Marine Supply USA, That is how I thought it would work. I have just reconfigured my system so that the Cerbo is on the Remote Port and the Multiplus on it's port. It doesn't allow the Multiplus to be configured from the Cerbo and one of the "Enabled" LED does not light up. The diagram on the Victron site is clearly wrong and the advise given to @Brent1982 was I can only conclude incorrect. The only question for me, is will the Smart Dongle plugged into the Remote port allow the iPhone app to control the Multiplus current limit and on / off / convert only / charge only settings. Once I get my hands on one I will test.

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bathnm avatar image bathnm bathnm commented ·

Tried to connect a Smart Dongle to the remote port and wouldn’t work. The enable LED on the BMS would not light!

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bathnm avatar image bathnm Matthias Lange - DE ♦ commented ·

@Matthias Lange - DE, Been looking at getting the Smart Dongle and connecting it so at least I can control the Multiplus when a VE.Bus BMS is in use through my iPhone. However, looking at the manual (https://www.victronenergy.com/live/vebus_smart_dongle_manual) it clearly says that the "Input current limit and on/off/charger only control" is not supported when a VE.Bus BMS is installed. Is the manual now out of date?

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ bathnm commented ·

@Brent1982 @Bathnm

I thought it schould work but I will test it as soon as possible at workbench.

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medavdsn avatar image medavdsn Matthias Lange - DE ♦ commented ·

Watching to see the answer to this as I'm getting ready to order some stuff and would prefer to not get a DMC

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bathnm avatar image bathnm Matthias Lange - DE ♦ commented ·

I did some testing today, and as per documentation it dose not work. When you plug the VE.Bus Smart Dongle into the DMC socket of the VE.Bus BMS the Enable LED goes out.

I re-wired my BMS to provide a signal into the Multiplus Aux 1 (Charge Disconnect) and Aux 2 (Load Disconnect) and changed the Assistant to 2-wire. Plugged the VE.Bus Smart Dongle into the Cerbo VE.Bus port. Disconnected the VE.Bus Cable from the VE.Bus BMS andI was able to change the stat of the Multiplus by either the Cerbo or the VE.Bus Smart Dongle via my iPhone and bluetooth. Disconnect the Load Disconnect and the invert switched off, Disconnect the Charge Disconnect and it went into float.

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medavdsn avatar image medavdsn bathnm commented ·

Thanks for letting us know the results. It is annoying they don't have a better way of controlling current limit and Multiplus mode when the VE.Bus BMS is involved.

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bathnm avatar image bathnm medavdsn commented ·

You can control current on the Cerbo with a VE.Bus BMS installed. You just can't change it's state. Anyway using the 2-Wire BMS Assistant on the MultiPlus and disconnecting it from the VE.Bus, what functionality is lost by not being connected to the VE.Bus.

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