I ran it down and went there with a very low battery so 2% is probably right. At this point I barely look at the GOM - I have a scan gauge that shows me real time data on battery SoC and energy-to-empty. It did seem that the values reporting to the station were not correct as it went along, but the control program was written for a Focus with the smaller battery. Some of the math and bit conversions for what the car reports are really weird, so I would not at all be surprised if reporting the larger battery values requires a different encoding method.
Along the same lines, I need to try and figure out if there have been any changes in the SOBDM that relate to that larger battery. When Sefs built the stack of chargers he made sure to have them setup with the same FW version as his onboard charger, which would ensure that their behavior would match the normal on-board charger. There are temperature related de-rating factors, voltage thresholds, etc that may not be quite the same for this battery. It's just an unknown at this point.
I've been reading through the code and writing verbose comments on what is being done. It seems like it should be possible to extend the car side function to work with multiple vehicles so long as their specific data points can be defined. Essentially making "profiles" for different models. To that end, I am actually looking at the possibility of consolidating all those various boards into a single shield that could mount on top of the Arduino Due that is running this right now.
All the signals need to be well isolated electrically or the DC charger will refuse to operate. All the car side stuff is separated from the charger signals by way of optoisolators and similar components. The large board in the top left of the photo is an isolated power supply. I need to figure out just how much load is on it and see if a smaller board level component can do the job while providing enough impedance to ground. If that is possible, I should be able to layout a shield sized board that would just need to have the signal wires from the CHAdeMO port connected along with the control lines that trigger the contactors. You'd have 12V/Ground going into the Due along with the car side CAN connections and that would be it.
I can't guarantee how quickly this stuff will get done, but I'll certainly pass along updates here.
2012 Candy Blue FFE
33.5kWh battery pack
CHAdeMO DC Fast Charging