Additional CAN Interface for the Cerbo

DIY
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1

Cerbo provides 2 can interface, one for the RS450 MPPT using VECAN and a dedicated BMS-CAN. Unfortunately all “compatible” BMS CAN protocolls only allow one master battery per Interface.

Is there a possibility to add additional CAN interface hardware e.g. by CAN converters over USB hub? Are there already proven models/drivers and what to do that the data appears at the dbus?

2

The system officially only supports “one” Battery / BMS per Installation.

Some people are using a Battery Aggregator-Script to combine multiple BMS as one BMS representation on Dbus, but it has some flaws.

Best way is to connect multiple BMS-based batteries through the supported way, by chaining them together according to the possibilities of the respective battery manufacturer.

3

Just my 2 cents…

If those batteries are not in parallel, then there are two systems, which better to be handled by 2 Cerbos / chargers.

If those batteries are in parallel, then it should be considered as a single battery bank and daisy chained together at BMS level and then connected on one CAN connection.

If those batteries are in parallel but with different BMSes that don’t know how to talk to each other, then better to not connect them to Cerbo, set the proper voltages into the charger and let the BMSes do what they know to do best.

But point to your questions:

  1. You can add additional hardware to Cerbo to have additional CAN ports on USB ports - in fact BMS-CAN is a separate module inside connected to an USB port.
  2. The additional CAN hardware will not be taken into consideration as a BMS CAN port, because the Venus OS drivers are not designed to handle multiple BMSes on multiple ports - but you can try to design your own driver.
4

I’m using Shunt/Lynx Smart BMS for monitoring battery array of different manufacturers, connected in parallel via Lynx Power In. Every battery’s BMS responsible for safety of itself, while Shunt providing SOC for the Victron system to rely on. Not perfect, but helps when agile in battery bank scaling

5

This question was not about other possibilites to parallel batteries using smart shunt or like the battery manufacturer suggests. I also know the dbus battery aggregator script.

As far as I can see, recent Venus versions contains the gs_can socket driver as part of the kernel and support RV-C as well as N2K for one of the buildt in CAN ports while the other seems a dedicated BMS 500K CAN Port only.

What happens with Venus at enumeration of a USB2CAN cable ? Provides this all services to use RV-C, BMS and NMEA protocolls? Is there any recommendation of cables using the build in gs_can driver?