RS485 or CAN to batteries?

[richjgould]

Hi all,

I've got an absolute mishmash of batteries in my solar set up (2 x 5kwh Sunsynk - but of different generations!, and 2 x 10kwh 'unbranded' AliExpress specials). None of them seem to talk to each other as they should so this project seems like an amazing find.

I have a Raspberry Pi 3b set up with the waveshare RS485/CAN HAT ontop. The webserver runs well and I can see I've got a serial0 and can0 device on the Pi so I think I'm good to go.

All the manuals for the batteries and the inverters say they all support both CAN and RS485 but is there a recommended way of using both? I've assumed I'll need to pick one communication protocol to talk to all the batteries, and the other one to talk to the inverter?

In the absense of some manuals, is it fairly standardised across manafactures than pins 1&2 (and 7&8) are RS485 and pins 4&5 CAN?

thanks
Richard

[ai-republic]

Hi @richjgould,
glad you found this project 😄
Yes, this project should help you out getting all your different BMSes connected and aggregated data sent to you inverter.
I personally prefer CAN if they support CAN. Now to your setup:
Do all of your BMSes speak the same communication protocol? The most common is the Pylon protocol that many manufacturers support (including SunSynk and Deye). For the AliExpress specials - what BMS do they use?
If we can get all BMSes to speak the same protocol that would be great as you only need one CAN hat.
If we need to support different communication protocols you will probably need another CAN hat (they can be stacked).
To the wiring, yes. often the pins 4 & 5 are CAN H and L (not necessarily in that order though)