Chevrolet Volt DC/DC Converter
Chevy Volt DC-DC converter
Ratings: Model number MSE465D (2012 and earlier) and MSE716 (2013-?). Input: 350Vdc nominal 260V-420Vdc Output: 12Vdc @165A, 2.2KW Efficiency: >90% above 40A output. Dimensions: 13” X 9” X 3.5” (including mounting feet and factory installed plastic air duct) Weight: ??? (including factory installed plastic air duct)
DC-DC functional Overview The Chevy Volt DC-DC converter is a high voltage to low voltage DC-DC converter and goes by several names including “APM (Auxiliary Power Module)” and “14V Power Module”. It is manufactured by TDK and is CAN controlled, and air cooled. It requires an external fan to provide the necessary air cooling for operation. In the Volt the air cooling was supplied by a blower that was ducted to the heatsink. In tests outside the vehicle it was found that by removing the plastic duct, a 120mm fan blowing onto the heatsink provides adequate cooling. The converter is not waterproof and was mounted inside the trunk of the vehicle. It needs both hardwired enable inputs and CAN control to function. The Ignition and Accessory inputs need to be connected to +12V and CAN communication established before it will turn on. The CAN data necessary to command the converter is a single CAN message at ID 0x1D4. This message commands both an enable and the voltage command. Placing a value of 0xA0 in byte 0 will turn the DC-DC on and a value of 0x00 will turn it off. If CAN communication is lost to the DC-DC after it has been initially commanded to turn on, it will remain on but drop to 13.5Vdc. It will then remain on until the ignition and accessory inputs are disconnected from 12V. Testing had been performed on the MSE465 model and the CAN documentation herein verified to be correct. The MSE716 is assumed to be the same but has yet to be verified.
Connectors: There are three connection points on the DC-DC converter. The High voltage input connector, the low voltage output studs, and the low voltage IO connector. The low voltage output is two M8 studs, one for power and the other for chassis ground. It is recommended to use a minimum size of 1awg wire for these connections for the full 165A current rating. On the MSE465 the high voltage input is made by a pair of orange wires about 2 feet long which terminate in an Orange Delphi connector part number 13861584. The connector that would mate to this would be a Delphi part number 13756860. The orange with red stripe is the positive and the orange with the black stripe is the negative. Both of these wires are shielded, so attention is needed if the connector is cut and stripped so that high voltage is not applied to the shield. The Delphi connectors are very difficult to obtain. It is assumed that most users will either cut the existing connector off and use a commonly available connector or splice them to lengthen the wires. Another method for connecting the HV DC input is to replace the orange wires completely. With the cover removed, the orange wires simply connect to the PCB using ring terminals and M4 screws. Removing the cover will have no effect on it’s weatherproofing. The screws holding the cover on are T-30 security head M6x20mm. On the MSE716 the high voltage DC input is made by an Orange Delphi connector mounted directly on the case. The connector on the case is Delphi part number 13743443. The correct mating connector is Delphi part number 13861584. Coincidentally the required mating connector is the one that comes attached to the MSE465. It would make no sense, but the MSE465 would plug directly into the MSE716 as the connectors are the same but opposite gender. The low voltage IO connector is a 10 pin 0.1” spacing connector on both the MSE465 and MSE716. The mating connector part number is AIT2PB-10P-2AK and pins are part number SAIT-A02T-M064, both of which can be sourced from Mouser. Pins 1,6,7,8 were used to simply provide termination in the vehicle. Pin 1 was connected to pin 8 and pin 6 connected to pin 7. If the DC-DC converter as not the endpoint of the CAN network, then these pins can be left unconnected.
- Pin 1 termination resistor
- Pin 2 CAN Low
- Pin 3 CAN High
- Pin 4 NC
- Pin 5 Ignition (12V input from key)
- Pin 6 termination resistor
- Pin 7 CAN Low (same as pin 2)
- Pin 8 CAN High (same as pin 3)
- Pin 9 NC
- Pin 10 Accessory (12V output to run cooling fans?)
The CAN data bus is at 500K and uses 11 bit ID’s. In tests it seemed adequate to transmit the command at a rate of 100ms and the DC-DC didn’t seem to object to this.
Command ID 0x1D4
Msg is 0xA0 0xB2 0x00 0x00 0x00 0x00 0x00 0x00 (you can only send the first 2 bytes)
A0 is signal to start, to signal DCDC off just send 00 instead A0
B2 means 14Vdc output and likewise AF means 13,8Vdc
If CAN signal is lost DCDC will default to 13.5V output.
Feedback ID 0x1D6 (7 byte message) Byte 0 ?
Byte 1 ?
Byte 2 LV Output Voltage The DC voltage as measured on the output. The value is obtained by dividing by 12.7. For example if the value is 0xAC then The voltage would be 0xAC=172 / 12.7 =13.5VDC
Byte 3 Coolant or baseplate temperature 1 Temperature in degrees C with a -40C offset. A value of 0x55 = 85 = 45 degrees Celsius (85-40).
Byte 4 Coolant or baseplate temperature 2 Temperature in degrees C with a -40C offset. A value of 0x55 = 85 = 45 degrees Celsius (85-40).
Byte 5 LV output Current The output current of the DC-DC converter. The value is scaled 1:1, so a value of 0x55 = 85ADC
Byte 6 ?
Feedback ID 0x495 (8 byte message) Byte 0 ?
Byte 1 ?
Byte 2 ?
Byte 3 ?
Byte 4 ?
Byte 5 ?
Byte 6 ?
Byte 7 ?
Reference photos: Here are two pictures of the DC-DC converter model MSE465 indicating the locations for the HV DC input, LV DC output and the LV IO connector.
Here are three pictures of the DC-DC converter model MSE716 indicating the locations for the HV DC input, LV DC output and the LV IO connector.
Here is a picture with the MSE465 cover removed. This illustrates how the HV DC wires are terminated inside the converter on the MSE465.
Here is a picture with the MSE716 cover removed. This illustrates how the HV DC wires are terminated inside the converter on the MSE716.
Here are two pictures of the mating IO connector.
Suggested wiring diagram: