I opted to go the poor route to add more charging power to my Vectrix VX1, and according to this viewtopic.php?p=80926&hilit=flatpack#p80926 thread I need isolated CAN bus, so I drew this. I want to control 3x Flatpack 2 (Non HE) in series. Got them from ebay about 66€ a piece. This should work with Huawei R4850 and R4875 based power supplies and maybe comes useful as a generic multi CAN board. Hope this is useful for anyone here. GIT: https://github.com/skrubis/esp-flatcharge
ESP32-S3 module
6~28V to 5V dcdc (there's TVS in front of it for 12 or 15V, so uprate if necessary).
5V to 3v3 dcdc
Isolated TWAI CAN
3x Isolated MCP2515 SPI bus CAN
Isolated Ignition input
CC PP for type2 - PWM input, resistance switching for state setting for EVSE
I hope no fundamental errors on my part, so do your own due diligence, will update when have a prototype up and running.
Probably should have included HV voltage monitoring and isolation monitoring, but did not want to add extra complexity, so in big scheme of things this is sketchy to say the least.
Attached is also a fork/simplified flatpack connector PCB, remade to be smaller/shorter, XT90 only, screw terminal AC in, phoenix pluggable for CAN. 4 layers as funnily enough 4 layers is cheaper on JLC than 2 layers with 2Oz copper.