Alternator- Parasitic Drag?

[Doc Sprocket]

While this thread (or idea) hasn't been touched in awhile, the concept is still open. I removed the magnets from one of my two flywheels. I am going to do some test runs when she's all back together, and see if I can detect a difference between the two. I really doubt the butt-dyno will show any change. I have recently acquired a radar gun, so I will see if top speed is affected (doubt that, too).

I am under the impression that the determining factor to the power lost is the current draw. The engine features magneto ignition, which is an entirely separate entity. The alternator is here for the sole purpose of charging the battery. The sole draw on the battery is the starter- so if I had to guess (and I DO) then the battery capacity lost in starting the engine would cause a slight power loss until recharged. If the battery is in good condition (it is new) and the tractor starts easily (it will), then the recharge will occur quickly- maybe only a minute or so. I believe the races are rolling starts, so the recharge oughta be done by the time the flag drops.

That leaves me with the other concern- the mass added to the flywheel by the magnets. That mass may slightly impair acceleration, yet benefit inertia. Hmmmmm.

Thanks for contributing, Tymoto21, and welcome to the forum!

 

[Tymoto21]

Thanks
Trying to do a electric kart for the cheap.
I have the parts to make a controller just don't want to drop $400 on a motor to get 15hp.

Or I will find a beat up 4stroke dirt bike to get an engine.

Also as far the alternator I would just stick a small 25aH batt on the kart with no charging system. Charge after each race.

 

[Doc Sprocket]

Gonna take more than that to crank over that big V-twin! LOL- You're new, so you wouldn't know this: The project in question is a racing mower with an 18hp Briggs opposed twin!

The battery is a 180Ah Lawn and Garden battery. Rules state I must have an onboard starting system, whether electric or manual. rules say nothing about charging.

 

[exenos]

I vote pull start!

 

[Doc Sprocket]

I vote pull start!

NOT!!!

I can see it now. There I am on the outside line of the track.Trying to hold the throttle open whilst yanking my dang shoulder out of it's socket cuz I jumped too hard off the clutch straightening 'er out it turn 3, stalling it- and she's flooded 'cuz I had it matted when it quit... Yeah. No.

 

[exenos]

They're not half bad to pull start actually, probably not much harder than a 9hp (never started a 9hp so its a guess) since the piston cycles are offset 360 degrees. My kohler has a 4" pulley on it and is just borderline on being able to start it with one hand, using a 6" its would be a piece of cake, but then again I'm comparing it to our four wheeler. Now that will literally dislocate your shoulder, I've done it twice while trying to start on the compression stroke.

 

[Doc Sprocket]

True, that. Pulling over my KVF400 will get you to confessing to war crimes after a few tries. That's a pretty big single, no compression release...

 

[devino246]

Shoot, ever seen an old John Deere started by hand? The compression release consists of a tube running from the compression chamber to a valve on the side of the engine, and you turn it over by turning the (smooth) flywheel.

 

[loud1]

Treat it as you would an aircraft engine and you should be fine.