Thanks for those ideas.

Some more resarch has revealed this data is all a single byte so I have deleted the second red herring byte that should make it a lot easier.

'MPI_MDL Temp C
'$9C = 21C
'$88 = 29C
'$83 = 31C
'$6B = 40C
'$67 = 42C

'DC-DC Converter Temp C
'$97 = 22C
'$7F = 33C
'$77 = 36C
'$76 = 37C
'$72 = 39C

'BAT_MDL Volts
'$91 = 152V
'$95 = 155V
'$98 = 158V
'$9A = 160V
'$9C = 162V
'$9D = 163V
'$9E = 164V

'MPI_MDL Volts
'$97 = 157V
'$98 = 158V
'$9B = 162V
'$9C = 163V

'MPI_MDL Amps
'$7F = 2A
'$7C = 8A
'$78 = 16A
'$83 = -6A

TORQUE NM
'$2D = 0 NM
'$3A = 8.4NM
'$41 = 28 to 30 NM
'$2A = -8.4 NM
'$29 = -11.2 NM

Any further ideas?