The original SY and SZ series cars were complex not just in terms of their drivetrain, but also in other areas, most notably the engine driven hydraulic braking and suspension. Apart from the fuel system, other well known weak points of the cars included the power steering & electrical system. In creating an holistic EV conversion design, it was necessary to take into account these peculiarities to provide a safe, reliable and performant solution.
For example, many EV conversion designs simply consist of bolting an electric motor onto the existing transmission, and adding some batteries wherever these can be fitted. Careful analysis revealed that an approach pioneered by Tesla, notably using a high rpm fixed gear AC motor in place of the rear differential, leaves sufficient room in the engine compartment for >85kWh of cells, giving a range of well over 200 miles. Since the original car's chassis was designed to carry a 6.75 litre engine and large GM TH400 automatic transmission, the overall weight is not substantially increased and front/rear balance is maintained, whilst losing no cabin or luggage space.
More details on the subsystem designs are available below: