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Discussion Starter #1 (Edited)
I have a 2017 Chevy Gen 2 Volt Battery, Charger, DC-DC Converter, coolant pump, 12V current sensor and associated low and high voltage cabling. I hope to reverse engineer these devices and use the components including the BECM and contactor module as a complete system controlled and monitored by an Arduino Due device (Machinna M2) and some associated electronics.

First up is the on board Charger (Part #24283105). This is an efficient and relatively compact charger.

If anyone has already reverse engineered it or has additional information on this device any info/help would be greatly appreciated.

Chevy Volt Gen 2 Charger Info
  • 3.6kW, Gen 1 Charger was 3.3kW
  • Approximately 5% more efficient than the Gen 1 (95%)
  • Located in the trunk beside the DC-DC Converter (AKA 14V Power Module, AKA APM)
  • Controlled and monitored by HPCM2 through PWM signals, Gen 1 was controlled through CanBus
  • Water cooled.
  • Given the efficiency and the flat top and bottom perhaps cooling with heat sinks and fans would be sufficient
The Chevy Volt Gen 2 Service manual is accessible for a minimal fee ($10 for 24 hours) at repairprocedures.com . Sign up, find the sections of interest and print them to pdf files for future use/study.


Control and Sensing Pins
The control and sensing of the device appear to be fairly straight forward. The unknowns are indicated in the pinout listing below. There may also be some required timing/order that the input signals, HVDC, AC signals are applied.
Looking into the cable connector (see img below) Top row (L->R) pins 6 to 1, bottom row pins 12 to 7 the pins are:

P2 BK - Ground

P3 VT/WH - Sensed HVDC voltage (PWM)
- DutyCycle - 0V = 10% greater than or equal 500V = 90%
- thus Vhvdc = 6.25*(pwm%-10)
- Frequency?
- 5V?

P4 YE/GY - HV Charging Control (PWM)
- Frequency?
- 5V?
- Duty Cycle Range?
- Controlling:
- amps or watts?
- AC input or DC output?
- Seems likely to be AC amps in order to stay within Elec code limits (i.e. liability)?
- The Controller in HPCM2 may calculate required watts then convert to amps and clip to current limits​

P9 RD/L-BU - Battery + (12v)

P10 L-GN/GY - Sensed AC Voltage (PWM)
- Duty Cycle - Less than or equal to 60V = 10% Greater than or equal to 280V = 90%
- thus Vac = 2.75 * pwm + 32.5
- Frequency?
- 5V?​

P11 L-BU/YE - 12V Charger Enable Signal


Note, the charger enable signal is always on while the car is running. This enables the traction battery voltage sensing (P3) which is probably used for failure detection and to determine if the precharge is complete. I suspect I will do the same.

Plea for Asistance
I own a Gen 1 Volt but do not have access to a Gen 2 volt. If someone does and would backprobe the connector it should be fairly ease to control the device. Recording the frequency, duty cycle and voltage on PWM Pins 3, 4, 10 with a DVM under the following conditions with a fairly discharged battery would answer most of the questions about the charger:
1) Car started but not charging
2) L1 charging at 8 amps
3) L1 charing at 12 amps
4) L2 Charging

Thanks in advance for any help/input.
 

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Hi Bilbo,

I'm starting on a similar adventure as you. I just picked up a battery, charger and DC\DC converter from a 2017 Volt and hope to install them in a donor car here within the next year or so. Have you managed to make much progress?
 

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I dug into this today. I have a 2016 Chevy and an salvage charger from a16/17 model. I opened up the salvage charger and swapped the plugs from the vehicle to this charger. I used the stock Volt EVSE for all testing. The stock EVSE can be used on 120 and 240. I did not measure my AC voltage today but I have measured 120V and 240V in the past.

I confirmed that the charge enable is always on when the vehicle is on. The 12V pin and that measured around 13V throughout all testing.

Battery voltage measured inside charger.

First off the frequency on all 3 pins was 100Hz (99.7 to 99.9) through all tests. I will not report those again below.

P3 - DC voltage sense
Car on - 350VDC battery measured, 8.3V, 66.3% duty
120/8A - 8.47V, 66.8%
120/12A - 354V battery, 8.2V, 67% duty (probably a bad voltage reading)
240/12A - 356V battery, 8.53V, 67.3%

P4 - HV charge control
Car on - 0.863V, 7.8%
120/8 - 5.15V 49.5%
120/12 - 6.7V, 57.8%
240/12 - 6.8V, 59%

P10 - Sensed AC voltage
Car on - 1.26V, 9.9%
120/8 - 3.8V, 29.8%
120/12- 3.47V, 28%
240/12 - 9.4V, 74.2%

Basically everything seems to be 12V, 100Hz PWM. With HVDC coordinating with duty cycle. Charge Control seems to be linked to AC current and Sensed AC is also coordinating with duty cycle.

Still to do measure P3 at various battery voltages to confirm curve. Salvage charger wasn’t running cooling so I did not want use it long for charging.








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Discussion Starter #4
Great work Nuts&Volts

That pretty much confirms that:
  • P3 HVdc = 6.25*(pwm%-10)
  • P10 Vac = 2.75 * pwm + 32.5
  • P4 controls the charge power/current
  • 12V 100Hz PWM is used for the I/O
However it s not clear to me exactly how the charging is controlled by the pwm on P4. If data could be recorded at the end of a charge cycle as the current ramps down this would help. Especially of the current was measured at the same points with an ODB reader (mygreenvolt works well on gen1 volts, gen 2?).

I hope to get back to this in the spring/summer and knowing the PWM is 100Hz and nominally 12V not 5V will help.
 

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Hi bilbo, I was wondering if you had ever figured out the control inputs for the 3.6KW charger? They seem to be very plentiful now and I feel that it would be the next step in charger high voltage batteries. I am building a 07 Mustang GT with a Tesla performance motor in it. Rear drive with the whole Tesla S rear suspension. This charger would really be a big help in the continuing project or nightmare depending on who's bank account you would be looking at. I am admittedly not real savvy in the realm of Can bus or PWM control although I am reading and learning. Any help or thoughts would be appreciated.
 

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Hi

I would also like to know if you were sucessful. I have an option to get one unit. It seems like a good liquid cooled charger.

tnx

A
 

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Yea they are both PWM controlled. I will be wiring mine (both Charger and DCDC) up in the next few weeks. Waiting on building my battery first


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