For anyone bound and determined to capture some wind energy, I'd suggest getting one of those boat windgen units and coming up with some sort of telescoping pole and folding blades so you can unfurl it when you park and capture wind energy WHILE THE VEHICLE IS PARKED.
That looks like the one on my buddy's boat that I saw putting out 20 amps into the 12 volt batteries in a 29mph wind and his blades looks about the same size - supposed to be a 600 watt wind generator on his boat.
In comparison, the best permanent magnet generators, such as those used for bicycle lighting systems, achieve an efficiency of around only 60%.
In terms of alternator efficiency, the conversion of mechanical to electrical may be very efficient, but it still goes into charging a battery which loses some efficiency, the laternator may only reach peak efficiency at a certain engine speed, so overall efficiency may be mucn lower than peak efficiency, etc... The alt efficiency clip was based off this blurb on diesel alternators. I'm guessing normal auto alts are the same or worse in terms of efficiency. 100% pure truth.
Originally Posted by FormulaTwo
I think if i could get that type of FE i would have no problem driving a dildo shaped car.
I haven't read all the responses here at the moment. But, to JanGeo, The idea of a clutching system was to alleviate the horsepower drain not stop the engine alt. from producing power. As for increasing the ram air system discussed. Have you thought about, or tried some type of funneling device to catch more air and accelerate it into a smaller more compressed area? I doubt the issue of extra drag from a system like this would truly be significant. I know a guy that drives his truck everywhere with the hood popped to the safety latch. This lets the hood sit up at least an inch. He claims he gets about a 3mpg boost on the highway just doing that. He hauls granite loads a lot and doesn't seem to thing there is significant drag.
just go freaking do it.
then tell us how it works out!
but seriously tho, only charging while moving etc....
the ram air will mess up your aerodynamics....
run it like this.... Put it in your back bumper, with a hole cutt for the fan, whatever u use to spin. make a scoop to it. THEN, have it so that it will capture the exhaust gas blowing onto it, as well as, the air you are generating while the car is moving.
So here's the concept a, 6-8" Ram air tube from the grill to an 6-8" blade assembly with a larger pulley to a half sized pully on one of these alternators. I have several hundred pages of alternator documentation(zip file) of how to pull this off. Looking for your thoughts. Also thinking that a solar panel could be rigged into the setup as well against the battery.
Interesting! Have you considered the power req'ts of spinning this alternetor assembly at some (lower?) RPM? Nothing is free...not even power-making devices; ie, it takes power to make (less) power! The law of conservation of energy prevails....And, have you considered the square footage involved with the solar collector...just to generate the current required to charge / partially charge the battery while "motoring" down the road? Wow! If it were feasible, the aftermarket would have scooped this up !
It would work wonderfully at highway speeds IMHO, but what about city driving?
I still think that finding a way to do this with the exhaust gases would be the best bet. If you could rig it up to capture both exhaust and wind that would be the best.
KetelOne, I have to agree with Matt here. I've only started on this forum, so don't take my word for it, but here's the logic:
Alternator belt on the engine driveshaft produces drag on the engine, and your idea will simply move that drag to the aerodynamics side of things.
However, the combined heat and kinetic energy of exhaust gases is higher than that on the wheels of your car (SIC!). Therefore combining a modified turbocharger and alternator/powersteering/AC/etc. would logically make more sense.