Quote:
Originally Posted by NeilBlanchard
With an electric motor you are losing only 1/10th the energy, so acceleration is not as critical -- and you can return 60-75% of the excess kinetic energy back to the battery with regenerative braking.
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Not even close. A reasonable estimate for full-cycle regenerative efficiency is 20%, with 30% being feasible.
Actually, by a generous interpretation, your statement isn't completely untrue, just misleading. It's possible to "return 60% of the energy back to the battery". It's just that you are going to lose another 15-20% with the battery charge/discharge cycle, and then be only 60% efficient returning that energy during acceleration. And be pretty much at 20-30% full-cycle efficiency.
Continuing my hope-vs-reality theme, I don't see the opportunity for a 43% overall weight reduction by replacing the steel with aluminum in a modern car. Most of the feasible drivetrain parts have long been lighter alloys, such as heads and transmissions cases. You aren't going to convert the brake disks, crankshaft or transmission gears to aluminum. And there are big chunks of the rest of the car, glass and interior furnishings, that will remain the same.