Tesla Model S/X DC/DC Converter
Overview
The Tesla Model S/X GEN2 DC-DC Converter is a popular candidate for EV conversions. It was first available in the Model S around Jan2014, and later in the Model X. It is located in the frunk area near the cowl.
It is not to be confused with the earlier GEN1 DC-DC Converter, whose casing was of a kidney-shape, was located in the RF fenderwell against the firewall, and it incorporated functions of the front HVJB; it contains fuses for the coolant heater, cabin heater, and air-condition compressor, and servicing these fuses was never supported by Tesla (though is frequently performed in the aftermarket), so it developed a reputation for being unreliable due to frequent replacement for blown fuses.
Wiring
HV connector: KET MG655776 type D
Note, be careful about which connector you get when salvaging this connector from Telsa wiring harnesses. Specifically, you want the key D variant.
- Orange (A/C): MG655773 (key A)
- Gray (fluid heater): MG655774 (key B)
- Brown (PTC heater): MG655775 (key C)
- Blue (DC-DC): MG655776 (key D)
Donor Harness: Tesla OE/OEM Part Number: 1032804-00-A has two Blue DC-DC plugs.
LV connector: Molex 0334721301
HV+ (positive) line is the one on the leftmost - opposite side of the red 12v output bolt.
For LV connector pin1 (top row) s the enable pin. Pin2 and pin3 are CAN H and CAN L.
Control
Although CAN control is an option, it is not necessary as the unit will run comfortably in failsafe mode (i.e. without any CAN input). Supply 12V to HW-EN (pin 1 on Molex plug), ground the case to the chassis, and the converter starts spitting out 13.5V. It has been mentioned that under heavy load the voltage may sag, so to enable CAN control see this OI forum thread.
CAN commands to request 14V at 500ms interval would be 0x2DD, but I need to provide additional +4 value to byte 1 because of enable bit value. Therefore 0x06 0xDD.
Msg is 3 byte long and value of data is swapped little endian so DD is byte0 and 06 is byte1
CAN ID 0x3D8 MSG DD 06 00
Reporting does not work if enable line is not high. Whenever i turn on enable i see reports.
Report is in telegram 0x210
0x210 8 bytes at 100ms
byte 2 = coolant inlet temp,
byte 3 = input power (16 W/bit),
byte 4 = output current (1 A/bit),
byte 5 = output voltage (0.1 V/bit)
Jason Hughes (wk057) posted this DC-DC Converter CAN information[1] in Jan2016:
