Mapping BMS RS485 to Venus OS

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Nicholas Herbst asked Mar 30, '20

Mapping BMS RS485 to Venus OS

Hi All,

I'd like to consider the development of mapping a new BMS, with regards to its RS485 registers, to the Venus OS on particularly a Colour Control GX.

I would envisage connecting the BMS via a Victron RS485 to USB Interface Cable and then using the Modbus-TCP protocol on the CCGX.

It seems to have been done already with the ZBM Redflow Battery BMS. See here: https://www.victronenergy.com/live/battery_compatibility:redflow_zbm

Can anybody point me in the right direction or offer any advice?

Thanks in advance,

Nicholas

BMS rs485

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Modifications Space

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Answer 1 · 2020-03-30T21:41:33Z

mvader (Victron Energy) answered · Mar 30, 2020 at 09:41 PM

Hi, sorry, but that won't work. You can't write BMS data to our system using ModbusTCP. The only supported protocol is CAN-bus.

The alternative would be that your driver takes the data from RS485, and then publishes it to the internal D-Bus. Doable, but tricky, there is not a lot of public documentation available - and in case there is ever some issue with such system all our support people have strict instructions to stay far away from it - as I hope you understand.

If you are going to do this, then I recommend to start with getting your hands on a system with a canbus bms, so you can see the D-Bus profile and mimick that in your own driver.

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Nicholas Herbst commented · Mar 31, 2020 at 10:35 AM

Thank you for the response.

Would it not be possible to "piggyback"/copy the solution that is in place for the ZBM Redflow RS485 BMS Communication?

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mvader (Victron Energy) ♦♦ Nicholas Herbst commented · Mar 31, 2020 at 10:44 AM

That code is no longer present in todays Venus OS version:

https://github.com/victronenergy/meta-victronenergy/search?q=redflow&type=Commits

That RS485 implementation was quite complex (handling multiple batteries and such) and ZBM then improved it by implementing a CAN-bus version of it: they now changed their system so that itself combines the information of all available batteries, and then it makes it into one coherent set of data.

So, we removed it.

For a framework of getting data from RS485 and then publishing it to D-Bus, better check this recently new project: https://github.com/victronenergy/dbus-modbus-client .

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Answer 2 · 2021-02-06T08:00:09Z

gro answered · Feb 06, 2021 at 08:00 AM

Have a look here, might not be exactly what you want but I think it will achieve the final result you are after.

https://community.victronenergy.com/questions/76159/victron-venusos-driver-for-serial-connected-bms-av.html

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