CANbus is the preferred interface between the Redflow BMS and a Victron Energy system controller (Venus / CCGX platform).
CANBus interfacing using the new ZCell BMS with built-in CANBus
The current BMS hardware has a built-in CANBus port. If you happen to have older BMS hardware without a built-in CANBus port, please use these instructions instead.
For this unit, simply cut the end off of an RJ45 patch lead and connect the bare wires into the BMS terminals as follows:
- Wire the BMS CAN H terminal to RJ45 Pin 7 (Brown/White)
- Wire the BMS CAN L terminal to RJ45 pin 8 (Brown)
- Wire the BMS CAN SH (shield/ground) terminal to RJ45 pin 3 (Green/White)
Connect to the CCGX
On the CCGX, there are two RJ45 sockets for the built-in 'VE.Can' port.
- Plug the RJ45 cable from the BMS into either one of the VE.Can sockets (doesn't matter which)
- Plug a blue Victron Energy CANBus terminator into the other port
It really does matter that you use this blue VE.Can terminator - the connection will simply not work without it!
Enable CANbus in the CCGX
Now the wiring is done, we need to enable the CANBus signalling path in the BMS and in the CCGX.
In the CCGX, ensure that CANBus is enabled in the Setup -> Services menu.
Note: The default CANBus baud rate is 500k for both the BMS and the CCGX. If you need to change to a different baud rate in the CCGX (e.g. to concurrently interface with older CANBus based Victron Energy MPPT units that run at 250k), then you need to also adjust the baud rate to match in the BMS (under Configuration->Network->Can) and reboot the BMS.
Check CANBus settings in the BMS
If you are not running at least version 1.6.0 on the Redflow BMS, upgrade to at least 1.6.0 because the CANBus support is automatically enabled in this version (and later).
The Configuration->CANBus page contains the BMS CANBus configuration values. The BMS starts out with reasonable defaults and in the first instance, while you can and should take a look, don't change anything on this page unless you have a reason to do so and you know why you are doing it.
Checking for connectivity
If everything has gone to plan, a new entry will appear on the main CCGX menu, showing the CANbus-derived battery system status from the BMS. This will be labelled "ZCell BMS" on current CCGX firmware - as per the screen shot below.
The CCGX needs to use this information to drive the operation of the energy control system. The CCGX System Settings page on the CCGX allows the configuration of the Battery Monitor to be used by the unit. By default (automatic selection) it should generally chose the ZCell BMS as soon as successful connectivity is established. You can also manually select the ZCell BMS as the battery monitor to use.
The recommended way to operate a Victron Energy system with CANBus is to enable DVCC - this enabling step is included in the step by step recipe for configuring the Victron/Redflow integration (in a separate knowledge base article).