Zeke:
a few observations and questions
first of all though i like your use of the brakedrum,, looks pretty good, but i would agree with bill you might want to
mount it a bit better to the flywheel.
it appears the drive ratio is about 4 to 1, or there abouts,, judgeing from the pics
your engine if i recall is rated at 8 hp @2600rpm
at 4/1 the alternator will be spinning over 10,400rpm which is an overspeed condition in my opinion
so you will need to reduce the engine rpm to maybe 2000 rpm with an accompanied reduction in hp
to about 6hp on a good day.
you will still be turning at around 8k rpm at the alternator,, not a speed that is in line with longevity of the alternator
again in my opinion.
6hp should net you about 150amps max when the alternator is at room temp and around 20 amps less when hot.
also it is popular belief to run the engine to about 75% capacity so you are down to about 4.5-5 hp and 125amps cold, and maybe
100amps hot?
based on this you might have to rethink your drive ratio, in order to get the alternator speed down to maybe 5-6k rpm
to do that you will either need to replace the alternator pulley with a larger one, or scrap the brakedrum in favor of a smaller dia drive
the ability of getting an off the shelf pulley for the alternator is problematic because it is either metric or some other proprietary size
i think you have a basis for a good battery charger, but as configured it appears to me that it is not going to work to its full potential, although
i have been wrong once before (ok,,, many times before)
i would be very interested in your theory of operation of this setup.
respectfully
bob g
