Multiplus - BMS - DMC Not functioning?

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d-h asked Feb 20, '24

Multiplus - BMS - DMC Not functioning?

Hi there,

I am trying to add a remote control (Victron DMC) to a Multiplus Inverter charger in conjunction with the BMS but when I connect the UTP to the 'Remote Panel' port on the BMS it seems to turn the Multiplus off. There is a mains sensor on the Multiplus and it is wired according to all the diagrams, are there settings on the Multiplus that need to be changed?

The Multiplus is located under the bed on a boat so it's a bit of a faff having to turn it on and off from there - a remote method would be great!

multiplus ve.bus

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Answer 1 · 2024-02-20T19:34:15Z

Justin Cook answered · Feb 20 at 07:34 PM

One thing I'll note is that you appear to have a battery -ve wire connected to the BMS, which is incorrect. When a VE.Bus product is on the system (which you have) the BMS -ve connection is provided by the VE.Bus cable, and a separate -ve cable must not be used. See section 4.2.1 of the installation manual: https://www.victronenergy.com/upload/documents/Manual-VE-BUS-BMS-EN-NL-FR-DE-SE-.pdf

That error shouldn't be causing the behavior you report, I don't think, but an error is an error, so should be corrected, and it's vaguely possible it's related.

The other obvious question is, what position is the Digital Multi Control switch in when you connect it to the Remote port of the BMS? If it happened to be in the "off" position, well... that seems too simple to even mention, but I've seen it happen!

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d-h commented · Feb 21 at 04:36 PM

Hi There,

Thanks for the answer, and good spot with the negative wire. I remedied that one, it should have been in load disconnect to the MPPT but I put it back wrong, so that's all working now.

I've tried it in all of the positions so far, it seems to sense an input the second I put it into the port and shuts down. I've also tried with the smart remote (bluetooth dongle) and no luck there either unfortunately.

So in theory it should just work when plugged into that port then without any changes to the multiplus? I did read in the BMS manual that it needs 'assistants' running on the multiplus but when I go to do that it wasy you must turn off the 'virtual switch' on the multiplus and i'm hesitant to change any base settings.

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Justin Cook ♦♦ d-h commented · Feb 21 at 07:24 PM

Well the odd thing is that the setup shouldn't have ever worked unless the required Assistant was already loaded into the MultiPlus, so I'm at a bit of a loss. Who installed and configured the system?

If you don't have an MK3-USB Interface already for your programming, it'll be worth getting one so you can connect to the system and see what's happening and make any corrections as necessary, or alternatively go back to the original installer for additional support and/or reprogramming as may be called for.

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Answer 2 · 2024-02-21T18:50:03Z

delf67 answered · Feb 21 at 06:50 PM

I may be wrong here, but I don't think your BMS is going to work correctly if you don't have the relevant assistant in the Multiplus. It states in the installation instructions:

"4.4.3. Load the VE.Bus BMS assistant or a ESS assistant in all units"

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Answer 3 · 2024-02-23T18:55:49Z

d-h answered · Feb 23 at 06:55 PM

Hi there both,

Thanks for the input. Really appreciated.

I set up the system myself so I may well have missed some steps.

Strangely though the BMS does appear to be working, for example it shut down the mppt when I removed the load disconnect connection.

I can install the BMS assistant but it says I must turn off the 'virtual switch', what is that and do I need it on?! I'm guessing I should install the ve bus assistant so I'll give that a go tomorrow (I do have the usb connector).

I suppose the main question is that should this be possible, which it sounds like it should be so I will persist.

I'm guessing I don't need the ess assistant though for a small boat set up?

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pwfarnell commented · Feb 23 at 10:09 PM

There are a lot of warnings that ESS should not be used on mobile systems such as boats and motorhomes.

If you do not have anything programmed on tje virtual switch function then adding an assistant should not cause any problems. It is a generic warning in case you have got something programmed on the virtual switch.

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