Chevrolet Volt 2 DC/DC Converter

Chevy Volt Gen2 DCDC P/N 24284603. It is a small and compact liquid cooled unit.

This unit does not work with CAN bus. It accepts a PWM signal which gives it correct key to start and provide desired voltage and constant current.

When i tried to provide good PWM signal there was something wrong. I couldnt get DCDC to start. I tried various PWM signals and duty.

I tried to start DCDC and when i connected 360Vdc i got 70% PWM on pin 3. This is signal HV is connected, but LV is not started. So far is good. Then i applied 12V 100Hz 75% PWM to pin 1 and …nothing!

No change in pin 3 and no 14V source. I tried 75% from 100Hz to 1000kHz… I figured pin 1 has some pulldown and when i gave it 12V via transistor i got 5V on the pin.

I connected 370Vdc to main connector. Then i verify LV connector pin3 is at 70% PWM. Then i use my signal generator and connect it to IRF510 Mosfet and i use 330R pullup to signal 75% PWM on Pin1.

I had 12V battery connected directly to output link behind the casing and feed 110Hz 50% duty PWM and DCDC came alive!

DCDC works with 110Hz up to 140Hz PWM.

Also i noticed that if i would remove the signal at that point DCDC would keep providing power regardless the signal. Later i would reduce duty to 40% and device would shutoff. The funny thing is if i would then remove this 40% duty signal DCDC would come online and provide power at 13.6V as failsafe.

PWM duty at 110Hz. Those values are under light load with 12V battery attached.

70% ……..14.2V

77% ……..14V

63% ……..13.8V

40% …….. OFF.

I also found out signal works down to 45% duty where DCDC actually stops.

I connected 1kW load of 9 H4 light bulbs directly to the output. I could measure 14V at 74A = 1kW! Supposedly it should provide 2.4kW power when liquid cooled.

I tried to run DCDC with 104S battery at 407Vdc and it worked. DCDC comfortably made 14.2Vdc under 1kW load.

Connectors:

HV connector from Mouser Aptiv P/N 33107347

I also got pins P/N 15446674

Only connector is not enough. You need to get the end cap P/N 13824779 with rubber seal P/N 15513451.

Also i got LV connector JST P/N ATSSPB-C0805H-1AK

I also got pins P/N SAIT-A03T-M064