electric fans as generators??

[aerohead]

*The fan is designed to move air
*It won't be efficient as a 'turbine'
*The best turbine is 57% mechanically efficient
*The motor as a generator might be 95% efficient
*Of the power you put in a battery you can get about 80% back out
*0.57X 0.95X 0.80 = 43.3@ mechanical efficiency,so with a perfect turbine behind the grille you'd get 43 % of the kinetic energy .

[hertfordnc]

That would be fantastic. The clutch sems to only be engaged less than 30% of the time when under a load. Under normal operations the truck does not create much heat.

So if the fans provided most of the power and the alternator took up the slack the overall result would be pretty good.

[Ryland]

Easy test, wire up a turn signal bulb to the fan and go for a drive, most turn signal bulbs are 20 watts, if it lights up bright while driving you might be able to charge at 1 to 1.5 amps, I bet however that it will hardly glow.

[P-hack]

The camber of the fan is designed to pull air in, not be pushed by incoming air, if you are thinking you are gonna approach 57% ME hertford, then you are in for a surprise. Well you are looking for a couple watts of "free" power on a 3.5 ton vehicle, so there is that too.

[hertfordnc]

Originally Posted by P-hack

The camber of the fan is designed to pull air in, not be pushed by incoming air, if you are thinking you are gonna approach 57% ME hertford, then you are in for a surprise. Well you are looking for a couple watts of "free" power on a 3.5 ton vehicle, so there is that too.

Yeah, well, it's definately not a prius. But my other car is a civic hybrid so my fleet average is still pretty good and my cost per ton mile is batter that most of you

I have no particular expectations of the results. I came up with the idea absent much knowledge of the physics involved and other people speculated on what my results might be.

I'll start by adding the fans to see what that does. I expect 1-2 MPG in the summer when the fan runs a lot. THen I'll experiment with powering the fans from a battery not connected to the alternator. If that provides an improvement then I'll figure out to charge the battery from either solar or the spinning of the fans.