Selecting “Large batterypack” at “Car Design” will always switch “Powertrain” category to “Electric Powertrain”.
While it is obvious that “Large batterypack” is useless for “internal combustion engine”, “Fast Engine” and “Super Fast Engine” (These are all pure combustion engines, right?) Large Batterypack should work with Electric Powertrain, “Fast Electric Motor”, “Super Fast Electric Motor” (and maybe even for “Hybrid powertrain”).
Unless I am of course missing something… 