You don't want a weed eater or similar engine. The noise will drive you
nuts and, weed eaters particularly, won't last very long in that
application.

I, too built what you suggest 30 years ago. Using no regulator at all,
I had to touch the battery lead to the field terminal for a second or so
to excite the field, then it worked fine. Our application was to charge
a large RV battery. We would fill up the tank when we left the place
and let the engine charge the battery until it ran out of gas. Worked
well. The engine was a 2 1/2 HP Briggs horizontal shaft. Mounted the
whole works on a 2 X 10 board about 2 feet long. Made a handel out of
some pipe and a tee.

Another thought:
Mount the alternator on a bicycle that is on a stand. I did this
years ago, too. I welded a piece of 2" water pipe to the pulley to
contact the wheel Added a field rheostat and a couple of meters. I
could get about 10 amps out of me for an hour or two without too much
strain. It made a great exer-cycle because I had infinite "load"
control with the field rheostat.
In my case, I put the rear wheel between the front forks and attached
the chain to it. It was easier to make a solid stand for the forks.
----GenaBike-----



Pete Stanaitis
-------------

RogerN wrote:

I've been thinking about mounting an automotive alternator on a small
gasoline engine to make a portable battery charger with respectable output.
The purpose would be to charge auto batteries when there are no outlets
around. Of course you could do the same thing with a generator and battery
charger but I think you can get perhaps 70 amps or more from an alternator.
It would have been nice this winter when we had the ice & snow storm and the
battery was weak on the seldom driven 4WD diesel truck. Also could be
useful for camping and boating, could recharge the trolling motor battery on
the lake, etc...

RogerN