CCGX and two CAN devices (BMS + MPPT)

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michaelsamer asked Jun 29, '24

CCGX and two CAN devices (BMS + MPPT)

Hello at Victron

I'm in search for an answer to my coming combination. Up to now Im using an OPzS System on a CCGX with two MMPTs and three Mulitplus II. One of my MPPTs was defective (VE.bus port failure) and was replaced with a CAN Version of it. As I was replacing the cable I chose (VE.)CAN as my new connection due to the much better possibilities of CAN.

Now I read on some sites that the generic VE.CAN of my CCGX could not cope with two CAN devices (esp. when a BMS is one of them like my planed from Pylontech) on the same bus which puzzles my knowledge so far.

Is there truly a 1 external device limit to the VE.CAN? Usual regulation defines 31/63/127 ext. devices depending on what version of CAN you chose. As I plan to buy another MPPT I'd have chosen the SmartSolar_250_85_CAN as wel due to "one system wide bus" idealogy of CAN. As my VE.direct and VE.Bus is already overloaded this seemed like a good way to expand.

Cheers

Michael

BMS CCGX Color Control VE.Can

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Answer 1 · 2024-06-29T15:24:01Z

pwfarnell answered · Jun 29 at 03:24 PM

VE Can devices can be daisy chained with a terminator at each end of the chain. So if you add another VE Can MPPT then remove the terminator from your current MPPT, and a new cable between your 2 MPPTs and put the terminator on the new MPPT. VE Can runs at 250kbps and no other speed. You could add a BMS to the VE Can port if the BMS can be configured to 250kbps but most can not so you can not normally run BMS Can and VE Can together. The VE Can port can be configured to 500kbps for BMS but will not then run your VE Can MPPT.

The Cerbo and Ekrano have 2 separate Can systems so they can run them at different speeds.

See Section 4.5 of the manual

https://www.victronenergy.com/media/pg/CCGX/en/connecting-victron-products.html#UUID-0963aebb-bb3b-4a8a-df4f-b02751010457

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Answer 2 · 2024-06-29T18:25:30Z

michaelsamer answered · Jun 29 at 06:25 PM

Hello pwfarnell,

that explains it pretty well. I'm working on my professional side with CAN since 1994 so I know my way around.

Quite sad for the part that CAN do support bitrate autodetection on most controllers (and most support all 1M...125kBit/s and often custom speeds as well), but working with fixed rates has it's pros. My Pylontech is (of course) running as highspeed device (500kBit). I'll go the way of reverting back to VE.direct (via USB) for my expansion and putting the CAN Version into the VE.direct mode as well; well it works.

Thanks for the fast answer

Michael

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