Quote:
Originally Posted by Newton
130lbs of additional weight would not offset a 10% gain in FE. The only time it would even have an affect on FE would be accelerating and going up hills. 99% of my driving is cruising on expressways and I live in Southern Michigan which is extremely flat.
Weight does play a role but for most people it's probably not as large of a factor as just getting things more efficient. Weight and power to weight ratios matter much more in things like racing.
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Not really. As long as the gas pedal is being depressed weight matters. If you are going down hill weight is good and if you are on a flat stretch of road cruising down from speed to a stop weight is good. Other than that if you can cut it its worth it. If you are having to accelerate to overcome drag you are having to accelerate that mass regardless of degree of climb.
Also if power-to-weight didn't matter then it would be just as efficient for us to cram as many batteries as possible regardless of weight.
That said adding weight thats not weight efficient(produces more HP per weight per cost) is fuel inefficient. So if solar panels cannot supply the power needed to feed the parisitic functions less than the alternator that is designed for that specific rpm range and torque(not terribly inefficient as long as its not feeding fans and compressors) then its not FE-friendly.
Solar panels at this point in time are not FE-frendly for standard cars. For Solar-racers its worth it because they weigh under a half ton with all surface area pointed directly up coated in expensive panels. Low weight allows for very low drain on the batteries and the panels can keep up with that. One Bp 375(75 watt hours in full sunlight on a non-humid day) for 400 dollars can probably keep up with power steering, brakes, and making sure ignition happens. Any fan coupled with standard draws will overrun your supply forcing the alternator on anyway and then you are hauling around a solar panel for no real reason.
If PV gets to say 40% efficiency we will see these all over the place but until then standard cars don't have much to gain from adding really expensive panels.