bathnm avatar image

VE.Bus BMS and Multiplus, remote switch off off Multiplus

Good afternoon,

Is there any configuration or assistant that can be applied that will allow for a remote switch off of the MultiPlus when used with the VE.Bus BMS and Cerbo GX. I know that in this configuration a DMC will allow this to happen, but I really do not want yet another panel to install (cost and space). I had hopped that a switch between the Left and Middle pins of the remote switch on the main board would work, but no luck. I am sure at some stage the ability to turn the inverter on and off through the Cerbo will be available, just as it is when no VE.Bus BMS is used.

My reason for asking is that when I leave the boat the MultiPlus, even with AES applied has been the biggest parasitic load causing a drain of 158Ah in just a week. Having turned the Multiplus off at the switch on the front the parasitic load has dropped to just under 0.2A. With the Multiplus on and in ~AES Search mode the system was drawing between .4A and .8A, occasionally going as high as 1.2A.

OK, I know I can turn the inverter off on the front panel, but that is a pain due to it's location.

MultiPlus Quattro Inverter ChargerVenus OSBMScerbo gx
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2 Answers
Paul B avatar image
Paul B answered ·

I had the same issue myself on site yesterday. the site has a VE BMS on it so the remote On/OFF will not work.

I could not remotley start the generator as some person had turn the system off via a emergency shutdown and thus the generator autostart feature was also disabled on the generator its self.

The battery was at a CRITICAL level like 8% left and the voltage was down to 23.8v the AC loads were 74 watts still and I could NOT turn the Inverter off remotely to stop the down-would draw, (not allowed as a VE-BMS is in use)

This is a VERY annoying restriction.

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I agree this would be an important function to be possible. I have run into this same issue ones.

Regards, Rob

Well the view is to get a DMC and use that to control the multi, turn it on / off / charge and set the AC input current. however this is expensive to purchase and then I have no place on the yacht to really install it. I suspect that the issue is not the Multi or the Cerbo/Venus OS, but the VE.Bus BMS and that to my knowledge has no ability to change the firmware remotely ;)

There has been hints that a fix might come, but no one from Victron or my supplier has been able to say definitively if they plan to fix or not. Victron come on please step up and let us know if there will ever be a fix or change to allow the Cerbo, VE.Bus BMS and Multi to play nicely together.

Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

You should be able to switch the Multi into "charger-only" with the right and middle terminal.
As long as no shore power is connected the Multi will be off.

If that is not working you can install the "safety switch assistant" and connect a switch to a AUX or temp.sense input.

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Thank you for the solutions. Switching to charger-only mode, via both methods, drops the current draw a little, but it is still 0.15A higher than the inverter and charger being off. It is such a shame that the ability to switch the inverter off just isn't available when you install a VE.bus BMS and do not have the DMC.

I just need to get my solar installed and then I will not worry so much.

Are there any plans to allow the Venus OS when a VE.Bus BMS exists to change the Multiplus mode and allow the shorting of the left and middle to turn the invert on?

If I remember correctly I read somewhere that there is something planned but I can't find it at the moment.

bathnm avatar image bathnm Matthias Lange - DE ·

Would someone from Victron be able to advise if there is something planed, or if the only way will be to purchase a DMC. I would hate to purchase a DMC and then find a short time later that I can actually control it via Venus OS.

Many Thanks

For what it's worth; I am betting on some improvements to be made to the VE.Bus Smart Dongle in exactly this area. It has additional connections already too, markings included, but not documented/programmed features as of yet.

just looked at a picture and there are 3 spare ports, maybe...... Just wish Victron would let us know.

I have the same problem. I have no need for the addition functionality of the DMC and really don't want yet another panel, especially when I bought the Cerbo to do it all. Since discovering that you can't turn the inverter properly off with the remote switch, I've just been using the charger only mode as off. I hadn't realised it's still pulling 5W though, unit I read this!

So chalk me up as another person who would very much like to be able to turn his multi off and on with a switch.

I just had a look at the safety switch assistant, but it say that it cannot be used with any other assistants that switch the power of the device (eg. the BMS assistant) and also that it doesn't turn the device off, just the AC output.