VE.Can Ports on MultiPlusII GX. Can-bus BMS & VE.CAN - run at the same time?

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cliff76 asked Feb 10, '24

VE.Can Ports on MultiPlusII GX. Can-bus BMS & VE.CAN - run at the same time?

I have a battery connected to one of the VE.Can Bus ports on the Multiplus2 GX. VE.Can bus port setting to 'CAN-BUS BMS 500kbs' . The battery communicates perfectly. But now i want to add one of the new Victron VM-3P75CT Energy Meters to second VE.Can port on the multiplus2. The energy meter has VE.Can bus ports, so I changed the VE.Can port setting to 'VE.Can & CAN-Bus BMS (250kbs )', hoping that i could run both the battery and energy meter at the same time. it doesnt want to work though. The battery drops off, and the Energy Meter doesnt stay connected - It connects and then drops off.

Can the system be run in this configuration?

When in 'VE.Can & CAN-Bus BMS (250kbs )' mode, is the VE.Can running at 250kbs, or is the CAN-Bus BMS running at 250kbs? Is there a way to change the data rate?

Cheers!

VE.Can

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Answer 1 · 2024-02-10T08:29:54Z

Alexandra answered · Feb 10 at 08:29 AM

@Cliff76

The Multiplus connects to the VE bus port not the VE can port.

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cliff76 commented · Feb 10 at 10:27 AM

Thanks Alex.. i think i may have got my terminology wrong. I meant to say V.E Can ports, not VE Bus ports..

It looks like i can only run both devices on the VE.Can if they are both set to 250kb/s..

I dont think im able to change the can-bus speed in my battery BMS. So i may have to use the ethernet port on the VM-3P75CT and connect via Modbus.

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Answer 2 · 2024-02-10T08:30:16Z

ejrossouw answered · Feb 10 at 08:30 AM

@cliff76 Why not use the BMS.Can for the BMS or is it the new MK II Cerbo?

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cliff76 commented · Feb 10 at 10:31 AM

This is the new GX in the Mulitplus2 @ejrossouw .. It only has two VE.CAN ports available.. There is no way to configure one for CAN-BMS and the other one for VE.CAN.. I wish it were possible to run both simultaneously. It looks like it can be done if the bit rate for both is 250kb/s.. But unfortunately the BMS bit rate is fixed to 500kbs.

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ejrossouw cliff76 commented · Feb 10 at 03:56 PM

My oversight. Yes it is just one port with two parallel connectors allowing termination or daisy chaining CAN.Bus devices.

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Answer 3 · 2024-02-10T08:51:48Z

Matthias Lange - DE answered · Feb 10 at 08:51 AM

You can only set 500kbit/s OR 250kbit/s.

If your BMS needs 500kbit/s it won't work on 250kbit/s.

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cliff76 commented · Feb 10 at 10:31 AM

Thanks for the info @Matthias Lange - DE

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Answer 4 · 2024-02-19T09:45:33Z

raketo answered · Feb 19 at 09:45 AM

Will there be an opportunity for this in the future?

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Answer 5 · 2024-02-19T10:01:06Z

pwfarnell answered · Feb 19 at 10:01 AM

@Cliff76 @raketo

it may be possible to put a CAN Bus baud rate converter on the BMS to swap that to 250kbps, such things exist in the vehicle world. I was looking at this myself for the same reason but have not actually done it so I can not confirm that it does work.

an example device in the UK is linked below, but search on Can Bus baud rate converter or CAN Bus bridge will find others.

https://rrrshop.co.uk/products/can-bus-bridge-baud-rate-converter

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cliff76 commented · Feb 21 at 02:53 PM

Thanks for the info @pwfarnell , that's very interesting. I'll look it up and do a bit of digging around to see if anyone has made this work.. It would save me running an extra network cable to the VM-3P75CT energy meter.

Cheers!

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