The Cerbo GX has 2 CAN-BMS inputs, but how can I extend this number to 3?
asked
How to connect 3 bms systems (REC bms) to a Cerbo GX over CAN-BUS
The CAN Bus is a bus, and so most devices have two ports. An "in" and an "out". You can daisy chain all the devices together with a terminator on the end devices.
You might want to use the BMS.Can port rather than VE.Can port.
I can't comment however if the Cerbo can handle 3 BMS's in the CAN bus. That is something you might want to test and or talk to your suppliers about.
I want to do exactly the same.
I already wrote to REC BMS and asked them whether this would work before buying 3 of their REC active BMS with Victron and Wakespeed compatibility. I'm still waiting for their answer.
Maybe REC and Victron could work together on this.
I think in a safety relevant environment, in the middle of an ocean, nowadays we are so dependant on electricity, that it is a perfect redundant approach to divide the house bank into 2 or 3 separate blocks. In normal ops they would always work in parallel like a single big bank. Should one BMS decide to isolate/switch off it's battery because of a fault within the battery and not with a charge source or a load, you still have a fully functional system and losoe only 1/3 of your capacity.
Of course I have designed my system the same way with all charge sources. For example if just one MPPT charge controller should produce a too high voltage due to a fault which is inside this charge controller, then only this one charge controller is taken off the system. There is no need to disconnect the whole charge bus in such a situation. Of course the BMS still can do this as a last line of defence. It's quite simple to do this with fully programmable voltage sensing relays.
Another reason to divide the house bank in 2 or 3 blocks:
I want to install a 1200 AH LiFePo4 bank and 2 VE Quattro 12/5000/220 100-100 and so the max peak draw from the Quattro's out of the house bank could be 1666,66 A. It will be very difficult to find bus contactor relays with such a rating. Whereas if you divide that bank in 3 blocks, each of the contactors (6 of them - 3 for the charge bus and 3 for the load bus) can be sized around 500 A and a peak tolerance of 700 A. So the Blue Sea Systems ML RBS would be an option.
Has anybody here implemented such a divided house bank successfully so that all data can come together in the Cerbo GX ?
