Actually, the limiting factor of an alternators output is it's internal
impedance. Thus, At a full load, it is only ~ 50 percent efficient. The
rest is given off as heat. That is why alternators need fans and you
really do not to keep them fully loaded. Add other inefficiencies in the
drive and yes, you can loose 5 hp running one.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of Ken Lewis
Sent: Friday, January 28, 2005 4:30 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Alternator upgrade note

jint,

If one horse power equals 746 watts then you should only need about two
hp
to turn the alternator. i.e. 120 amps times 13.8 volts equals 1,656
watts.
Which converts to 2.2 hp. Hmmmmm.
Ken Lewis
http://neksiwel.20m.com/