[NeilBlanchard]

The percentages are not the only consideration to overall fuel consumption. The displacement and power of the ICE required matters a lot; as does the powerband tuning. Also, the length of time you need to run the ICE matters a lot.

In a serial hybrid like the Zing! it would not be possible to get the ICE used for the genset to power the wheels mechanically and have anything like the performance that the electric motor gives. The valvetrain would have to allow for wider RPM powerband and thus would lose peak efficiency.

If it was a parallel hybrid, the ICE would have to run at varying RPM's so the efficiency would not be optimal except in some situations. And the ICE would have to be run continuously, rather than periodically.

And if you consider a typical long drive profile, which has a short period of slower speeds with stop and go driving at the beginning *and* the end, with a longer period of sustained higher speeds -- a parallel hybrid would possibly be left with a depleted battery and be forced to limp along on the ICE power alone. This would require a multi-gear transmission.

I would like to hear how the Zing! does for fuel efficiency in daily use in the real world, as a serial hybrid. And if it is possible to set up the ICE so that it could either spin the generator, or mechanically spin the rear wheel -- i.e. be both a serial and a parallel hybrid (but not a combination hybrid like the Prius and Volt) -- that would be very interesting, too.

Ken, have you considered do an energy/fuel log here on EM? I'm not sure if it is set up for both plugin charging and fuel use?