Building CAN message with Cerbo GX MK2

Node-RED
1

Dear community,

I’m searching to use a Cerbo GX MK2 and Node-Red to communicate with a third-party board.
My goal is to broadcast datas from 2 x MPPTs + 1 x Lynx BMS to this board.

Is anybody have any experience and/or example that will permits me to send those datas with a fixed CAN Identifier using the VE.can IO from Cerbo ?

Thank you for your interest and your help.

2

I don’t think that you can use the Cerbo’s CAN interface like this.
The CAN interfaces provided are dedicated for reading MPPT-CAN and BMS-CAN data. I don’t think that you can send ‘user’ messages over these interfaces.
If you want to access MPPT and Lynx BMS data remotely, the approved paths are to use either the Modbus data map, or MQTT (not used the latter).
If you need to use the CAN bus, if your MPPT data is also on CAN rather than VE direct, then you can extend the CAN bus, and get the 3rd party board to ‘listen only’ to the data. Decoding it is then your problem.

3

Hi, actually this is possible to do.

The canports on GX devices are available as standard linux socketcan devices.

(I recommend Google the term socketcan).

But how to do that is really something quite complex to explain and I can’t get into that.

All the best, Matthijs

3 Likes
4

Ps.

And

And aside from working out how to send/receive from node-red, you also need to check what can profile to set in the gx settings, or set that to disabled and then manually “up” the can interface and set baudrate and such

1 Like
Need to Get and send canbus messages via node red
5

Thank you for your comments.
I will try both Libraries.

6

Thank you very much @mpvader .

I will study the subject.

FYI, Currently both Can port are being used:

  • BMS port (Cerbo Gen1) is used to collect / visualize data from a High voltage battery using the pylontech profile

  • VeCan is used to control the 24V system with an MG ENERGY SYTEMS battery. System has MPPT’s and VE.BUS devices controlled by DVCC

There are other devices connected to the BMS canport @500kbs. Specifically a Bidirectional DcDc used to transfer energy from High to low or low to high based upon the respective state of the battery. and there is also a Shore charger direct charging the high voltage battery. Goal of the Red node flows I intend to create:

  • Virtual Charger to display Shore charger status
  • Virtual DCDC to display HV to 24V DCDC operation status
  • Generate control message sent to the HV DCDC to manage power flow between the batteries.

Hopefully we can achieve this without disrupting the existing canbus messages used by the Cerbo…

Thank you again…

JMarc