The datasheet I read did say 3.3v compatible, https://www.nxp.com/docs/en/data-sheet/TJA1050.pdf "Input levels compatible with 3.3 V and 5 V devices". I think it may be either, no CAN is 3.3v compatable, or just none of these Chinese transcievers.
Anyway I have some progress, I put the SetVoltage(42,false) call into the main loop. I put the VP230 back in, and tried the logic without the psu connected. Now it was trying to transmit and TX looks correct, but the CAN side is wrong.
I wanted to try 5v but didnt want to kill this chip (even if the datasheet says 6v max) so I put the TJA1050 in, I put a 1k/2k R divider on RX and gave the CAN 5v Vcc, which gave me this working output.
edit: The output is now correct, my changes must have messed something up.
22:32:38.211 -> --- HUAWEI R48XX INFO ---
22:32:38.211 -> Rated Current: 52
22:32:48.598 -> --- STATUS ----
22:32:48.598 -> Input Voltage: 246.91 V ~ 49.95 Hz
22:32:48.632 -> Input Current: 0.45 A
22:32:48.632 -> Input Power: 111.26 W
22:32:48.632 -> Input Temperature: 22.00 °C
22:32:48.632 -> PSU Efficiency: 91.02 %
22:32:48.632 -> Output Voltage: 48.86 V
22:32:48.632 -> Output Current: 2.07 A / 40.37 A
22:32:48.632 -> Output Power: 101.26 W
22:32:48.632 -> Output Temperature: 15.00 °C
22:32:48.632 -> Coulomb Counter: 0.01 Ah
22:32:48.632 -> --- STATUS ----
22:33:06.551 -> --- HUAWEI R48XX DESCRIPTION ---
22:33:06.551 -> /$[ArchivesInfo Version]
22:33:06.586 -> /$ArchivesInfoVersion=3.0
22:33:06.620 ->
22:33:06.654 ->
22:33:06.654 -> [Board Properties]
22:33:06.689 -> BoardType=EN1MRC5G1A1
22:33:06.723 -> BarCode=2102310FFALUH9011745
22:33:06.792 -> Item=02310FFA
22:33:06.827 -> Description=Function Module,R4850G2,EN1MRC5G1A1,1U 3000W Rectifier,Power Only
22:33:06.965 -> Manufactured=2017-09-27
22:33:07.033 -> VendorName=Huawei
22:33:07.067 -> IssueNumber=00
22:33:07.102 -> CLEICode=
22:33:07.136 -> BOM=
22:33:07.136 ->
Tried the VP230 again, no different at 5v.