I would like to give a short report on our work to create a Vehicle Control Unit that can communicate/control the Leaf inverter/motor assembly.
Now we have completed about 6 months of testing and revisions on our VCU, which controls a 2013 Leaf drivetrain in a converted Geo Metro.
Work started on this project by tapping into a functioning Leaf controller canbus and recording data in various drive modes. The spreadsheet with known canbus information from this forum helped us filter the data and understand useful messages. Member Celeron55 contributed critical data for calculating a checksum and cleared up a few interpretation issues.
We programmed our VCU hardware to send torque responses, and once we were able to test it on pavement, incrementally added multiple user friendly features. The following is a list of what we have so far. The Geo Metro runs very much like a production electric at this point.
- User configurable torque values: maximum, idle regeneration, brake regeneration
- User configurable Forward, Neutral, Reverse options using a SPDT switch and voltage divider
- User configurable minimum precharge voltage for main contactor closure. This ensures precharge is functioning
- User configurable maximum pack voltage during regenerative braking, with feathered torque commands to prevent pack overcharge
- Automatic throttle feathering at regeneration transitions, including floating zero torque position proportional to RPM
- User configuration values and various troubleshooting traces via Putty or Coolterm serial interface
- Torque based brake light activation during regenerative braking
The battery pack in the Geo started at 260 volts and is now at 400, comprised of modules from surplus packs taken from the 2008 MiniE (BMW) limited production. Total capacity now is about 35 KWH, which we estimate will provide between 140 to 180 miles range.
Here is a video made early in the ThunderStruck Motors project. Note the absence of the charger/DCDC module normally on top of the Gen2 inverter. The 3-point Leaf mounts required minor extensions for the Geo mount points. The half-shafts were cut and spliced between Geo and Leaf for the required lengths.
Many thanks to all of you who have contributed to information gathering for the Canbus Decoding project on this forum.