My partners dream car is a green outback, but she wants her next car to be electric and so far there are not many comparable vehicles that come in forrest green. 😆For the Rivian, it’s not just software. Rivian incorporated axle clutches in the rear drive units half-shafts that, when commanded by conserve mode, physically disconnects the drive units from the outboard portion of the shafts. This allows the rear wheels to free-wheel. The drive unit inverter can then turn “off” completely and the motor/reduction gears stop rotating. magnetic rotor/stator losses are eliminated, as well as all mechanical windage and reduction-gear/bearing friction losses. Hyundai/Kia also do that on the front drives of their e-GMP platform EVs, and Tesla incorporated axle clutches on their Semi’s rear driver axle set.
For the Equinox rear assist drive unit with an induction rotor, it likely will turn off the inverter in FWD-only mode and save energy there. But axle clutches are $$ and outside the price/value box the Equinox is designed for. There will still be windage and friction losses as the rotor and gears idly spin, plus the rear unit’s always-present extra weight. An Equinox EV will likely replace both my 2013 Volt and my wife’s 2013 Subaru Outback, so a cost-effective AWD version w/ towing capacity (and blue paint) is a necessity.