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Hello.
I am working with SimpBMS, which is supposed to connect to a GX device by VE.Can. Got it working by changing the CAN-bus(1) profile in Settings->Services to 500kbps.
My questions:
Why are there two CAN-buses shown (1&2)?
What is the difference between VE.CAN, VE.BUS and BMS-CAN on the Cerbo?
Does the Cerbo have two separate Bus systems, as the settings menu suggests, and if so to which ports on the Cerbo do they apply?
Hi @Basti
The Cerbo GX has two CANbus interfaces. They are independent from a data and connected device perspective. They are not electrically isolated.
One is labelled VE.Can, the other is labeled BMS-Can, with a screen print on the top side of the unit when it is facing towards you. These each correspond to the 'VE.Can port' and BMS-Can port' listed in the services menu of the GX software.
By default;
VE.Can is set to 250 kbit/s
BMS-Can is set to 500 kbit/s
VE.Can is intended to be used for the Victron (and Victron compatible) VE.Can products, such as the VE.Can MPPTs, and VE.Can Lynx Shunt. You can string these VE.Can 250 kbit/s devices together along this bus.
It must be terminated at both ends with the included VE.Can terminators.
BMS-Can is intended to be used with compatible managed battery systems, such as Pylontech, BYD, Freedomwon and many more. These must be terminated at the Victron end (on the Cerbo GX) with the included terminator (same one as used with VE.Can). It may or may not be necessary to terminate at the managed battery, BMS or BMU - this will be documented in the specific Victron Compatible managed battery instructions for that battery. Some batteries automatically terminate.
You can't mix VE.Can and BMS-Can on the same bus. That is why there are two seperate buses, each with 2 RJ45 ports - 4 CANbus ports in total.
You cannot set the BMS-Can ports to anything other than 500 kbit/s, and disabled.
You CAN set the VE.Can port from 250 kbit/s to be 500 kbit/s (or one of several other CANbus speeds for other CANbus applications).
Other types of Batteries and BMS may claim compatibility with BMS-Can, or VE.Can, but if they are not on the battery compatibility list then they have not been tested and confirmed to work by Victron. So they are at your own risk, and the supplier that made the claims responsibility to support.
One extra element of possible confusion is that there ARE some BMS products on the market that use a CANbus BMS profile at 250 kbit/s. These can only be connected to the VE.Can port, and it must also be set to match this (VE.Can & CAN-bus BMS (250 kbit/s)) in the services menu for the VE.Can port.
These BMS can be used in the same cable daisy chain as other Victron VE.Can devices.
just some general feedback...
thought I could save the customer a few bucks by installing a cerbo when he upgraded to pylon (instead of replacing both 150/70 CAN mppt charge controllers to TR) doesn't want to pick up the pylon battery on the Can BMS... so I guess the solution doesn't work that way... first tested if comms are fine on old ccgx by changing to 500bps prior to installing cerbo - comms were 100%. what am I missing?
Hi.. did you resolve this? I'm in same situation, 5x old 150/70 chargers and a ccgx.. and new pylontechs on their way...
Was gonna swap ccgx to cerbo.. now worried..
W ehave systems working with Pylons and mppts on Can with no issues.
Just follow the victron Pylontec guide
