Earlier quoted context omitted.
My calculations ( http://daniellefong.com/2008/11/15/tick-tock/ ) give about 4 kwhr per 100 miles of city driving without regenerative breaking at about a 70% efficiency. Most of the US ranges between 2 to 4 kwhr a day of impinging sunlight - let's call it 3. High efficiency PV panels are about 30% efficient, so this is about 1 kwhr per m^2 of charge per day. This would give about 25 miles of city driving, which is w…
Thanks! So if you add in the weight of the panels, and the occasional patch of cloudy days - I think it might be a bit marginal... Would you agree? I hadn't really considered regenerative braking. I can see how it would be useful in a place like San Francisco, but I'd wonder how effective it would be in places like NY (where you need to slam on the brakes instead of just curb your speed). I recall reading about a min…
Re: What can Tata's Nano ($2500 car) teach Detroit?
#31To make quick regenerative braking efficient, you need something other than batteries to store the energy -- they can't absorb that much power so quickly. They're working on ultracapacitors, which seem like an expensive solution to me. Our strategy, which is also used by so called hydraulic hybrids (in garbage trucks, most notably, which are constantly stopping and starting), is to compress air during braking: this can be done quite quickly and efficiently, and avoids conversion losses. We were expecting a cycle efficiency of between 70% and 80%. We're not working on vehicle technology at present, though.