
Volt facts....
How it works:
It has a 16 kWh battery, of which all but 9.6 kWh are 'off limits' so as to extend the battery life; basically the computer won't let it discharge below 30% or over 90%. Said battery is warranted for 10 years or 150,000 miles.
The electric motor is a 3 phase 600 volt unit of 161 hp/45 kW (100 KW peak). Like all electric motors it's vastly more efficient than an ICE and gets its maximum torque from 0 rpm vs. over 4,000 rpm for a gasoline ICE.
Slow it isn't. Volt can blister a lot of cars on the road.
The range extender/generator is a 1.4 liter normally aspirated 4 cylinder with a 53 kW generator attached. This runs at very specific speeds (depending on load) and only comes on when the battery is at 30% or if the battery is too cold or too hot. This is in order to power the car until the batteries environmental controls bring it into the normal temp range, at which time it shuts down and the battery takes over. It also starts up occasionally for a few minutes just to keep its innards lubed.
Full time electric drive, no 'helping the ICE' only at low speeds like most hybrids.
The range extender powers the car by generating electricity which is buffered by the battery on its way to the electric motor. Very few losses compared to a conventional drive line.
No transmission, so no losses there.
Regenerative braking - stopping recharges the battery.
For the first 40 miles it runs on electricity only, then the range extender fires up and can power the car for an additional 300 miles.
They were going to use a larger tank for a 500-700 mile range, but so little gas was being used in tests it started to stratify so a smaller tank with a magnetic stirrer was subbed in. Besides that, how many people can hold their water 500-700 miles? :-P
Operating costs (based on $2.50/gallon gas and the overnight off-hour electric rate for the Detroit area)
Charge time @120v: 6 hours
Charge time @220v: 3 hours
Cost of overnight charge: 40-50 cents
Cost/mile in EV mode: ~1 cent per mile
Cost/mile in range extender: 3 cents per mile
Cost of an ICE 30 mpg car: 10 cents per mile
Energy efficiency and availability:
A study by the EPI and a green group was done 2 years ago and it showed that existing generating capacity in the off hours is more than sufficient for EV's in the foreseeable future. In addition to this most new generation for the last ten years is natural gas, not coal.
All told the efficiency of an EV power path runs like this: 72% for the car, 40% for the power plant and 90% for charging. This results in an overall efficiency of about 26%.
Buy a solar panel, put it on the roof so that you can sell power back to the utility, then use just part of it at night to charge the EV and that goes way up to almost 65%. Such panels are already on the market and getting cheaper very fast.
A run of the mill ICE powered car is lucky to get near 20% for the vehicle and then you have to account for the processing of the fuel.