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jordifax avatar image
jordifax asked

250 Kbits/s battery on Multiplus II-GX ?

Hello!

We are installing lithium batteries with their own BMS working at 250 kbits/s using EasySolar-II GX and Multiplus-II GX units. It seems the Multiplus-II GX units do not have the 250 kbit/s baud rate option, as do all the other GX units.

can-500-kbit-only.jpeg

Is there a way to get the Multiplus-II-GX to work at 250 kbit/s? Changing firmware perhaps?

The batteries have been tested with a Color Control GX and work fine. But it is not working with the Multiplus-II GX.


Any help is appreciated. We have 450 units of those standing by...


Regards,

Jordi Faxedas

Multiplus-IICCGX Color ControlVE.Cancommunication protocol
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5 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

The MP-II/ES-II GX are only compatible with 500kbps and this can't be changed because it is a hardware limitation.

https://www.victronenergy.com/live/venus-os:start

"14. The CAN-Bus port of the Maxi GX, MultiPlus-II GX and EasySolar-II GX is a BMS-Can port. It can only be used to connect to managed batteries such as Freedomwon, BYD, Pylontech, BlueNova, MG Energy Systems and others, at 500kbps. Note that some early production batches had a labelling mistake: the port was labelled VE.Can. Which -unfortunately- is wrong. The hardware does not meet the requirements for a VE.Can port; and therefor is BMS-Can only."

If you have a 250kbps BMS you have to use the "normal" MP-II + a Cerbo GX.

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jordifax avatar image jordifax commented ·

Hi Matthias,

Thanks for the information, found that as well. But now it is too late for hardware changes from my side.

When I bought these units it was sold to me as a VE.can port... See below the screenshot of the datasheet we included in our bid offer. This was for a large public tender, so it is becoming a critical issue now and we do not have budget to exchange 450 units and add Cerbos to all of them.

vecan-multiplus-ii-gx.jpg

Is it not something that can be solved by software?

I don't understand how the communication speed can be a hardware limitation? I am no expert in communication, so if you can explain it to me it would be much appreciated.


Thanks for your time,

Jordi

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

I'm also not an expert at this topic but it's written in that link above.

As written above it was mislabeled in the very first batch (1.5 years ago?). I'm sure the datasheet was corrected quickly.

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Marty avatar image Marty commented ·

Hi Matthias and Community,

Thanks for response. As also ask in this thread,wkirby indicted " VE.Can port is galvanically isolated and the BMS Can or Second Can port is not galvanically isolated. " Could you help me clarify some term:

1. Are we saying that BMS-Can port and CAN-bus ports are the same?

2. Are we saying the BMS-Can port / Can-bus port are really the VE.bus port?

If NO to either

3. Where are the BMS-Can ports on the MultiPlus-II GX ? ( I only see VE.bus port but yet from the table at [1].(14) it indicates that the MultiPlus-II GX has BMS-Can port and the Can-bus port is NON-Isolated where as the VE.bus port are Isolated )

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mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi Jordi, I’ll contact you by email; either myself or will make sure someone else does, might be tomorrow. Matthijs

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jordifax avatar image jordifax commented ·

Thanks Matthijs, appreciated.

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Claude Leveille avatar image
Claude Leveille answered ·

Thank you very much for infos.

Claude

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alan avatar image
alan answered ·

You can buy CAN bus speed converters (not from victron), 500 to 250 are available.

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Marty avatar image
Marty answered ·

Try plug the battery into the VE-CAN port on the CERBO rather than the BMS-CAN port and set CAN-1 settings to VE.CAN & CAN-bus BMS (250 kbit/s)

like was done by

https://www.offgridsoftwaresolutions.com/ws500-user-forum/topic/connecting-my-rec-bms-to-a-victron-cerbo/

also see

https://community.victronenergy.com/questions/118934/bms-can-ports-running-the-vecan-nmea2000-protocol.html


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