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RE: Powering Stuff *Directly* From Solar Panels Feels Like Magic!

in #technology7 years ago

On the off chance you're being serious, the problem with putting wind turbines on cars is that they add drag. The drag from the turbine costs more energy to overcome than it can generate, otherwise you'd have invented a perpetual motion machine.

Likewise with the suggestion that you use the rotating portions of the drivetrain to spin an alternator. Gas cars do this only because they need electricity to keep the starter battery charged. It still takes kinetic energy to spin the alternator, which consumes an amount of gas the energy equivalent of which is greater than what the alternator puts out.

Now, regen braking is sort of like what you're discussing. But it is only used to turn the car's momentum back into electricity when you want to bring the car to a stop anyway. That's energy that would otherwise be wasted, converted into heat by the friction of the brake pads.

If you had regen on not just while braking but all the time during driving, it would decrease the range, because it takes more energy to spin the alternator than you get back from it. Otherwise, again, it would be a perpetual motion machine.

I am surprised to hear such questions from you, as I remember you being more knowledgeable about engineering principles than that.

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I really do not have much knowledge of engineering principles. I know that turbines do add drag and that with a gas vehicle would not be efficient, but when solar and electricity are use even a small wind driven generator, it seems to me, could be used to provide power to the non propulsion systems, such as the radio, the headlights, brake lights, etcetera, I remember as a kid a small clip down on the bike wheel for running the headlight on my tenspeed, not a big generator, but enough to run the light.

Because the bicycle was muscle powered. The energy generated that way is not free, it comes from your body. Adding a wind turbine to an electric car, even to power non-propulsion systems, is pointless since it costs energy from the car's propulsion battery to move the car in order to make the turbine spin. The energy still ultimately comes from the main battery, you've just added an unnecessary conversion step in between. It would be less wasteful just to power all that stuff from the main battery, which is why that's how all electric cars do it.

Solar is a different story though and makes good sense. There exist electric cars with solar roofs for powering a heat pump, which keeps the temperature inside the car from getting too high when it's left parked outside in bright sunlight.