using real horsepower

[TheEquineFencer]

I've been kicking this idea around for a while. I have horse that I can hitch and drive. I'm thinking about takng a rear wheel drive car rear end and rigging a 12V alternator to the input yoke and using it to charge 4 group 31 car batteries. I figured I could just manualy excite the alternator after I start moving. Do you guys think it would "bog" the horse down if the batteries are dead? I'm guessing I could kill two birds with one stone doing it this way, get to go out for a nice drive and charge a set of batteries at the same time. I usually hitch her up and drive for an hour or so at the time any way.

[Frank S]

You have 3 problems with this all are somewhat solvable
 #1 you need a very freewheeling diff unit . My old 49 chevy 3100 is so freewheeling that a 10 year old girl can push the pickup fast enough for my wife to start it if the battery is too low to turn the engine over.
#2 Once the horse gets the cart or wagon moving the flywheel effect of the kinetic energy that will build up in the gear train and rotor could push the poor horse.
 #3 you will need to gear up your ratio to get the ALT spinning around 1200 to 2000 rpm before it will do much of anything 2500 up to 4000 would be even better and depending on the alt.
A horse pulling a cart or wagon even lightly loaded is not going to be moving much over 3 to 5 MPH. If you are going to Wells Fargo the poor beast then about 10 to 15 MPH and Pony express at 20 to 25 is going to put him in a lather pretty quick. Be sure to consider that gear trains eat up HP real quick.
 A much better solution may be to have a wagon or cart with  narrow tires inflated to have the lowest possible rolling resistance possible then install a high ratio chain or low friction belt drive  Remember a tire about 34" in diameter is only turning about 29 to 30 rpm @ 3 MPH and you will need at least 1000 RPM for most non modified alts
 Still doable as long as your expectations are not too high   

[madlabs]

Now I don't know if a real horse = one horsepower. You'd think but...

Anyway, 1 hp = 740 or so watts. I dunno how much a carriage costs, hp-wise, but assuming 1/2 to pull the carriage leaves 350 watts, minus mechanical and electrical overhead for the alt, doesn't seem to leave much left over for power production.

Jonathan