Someone asked in a previous post what the difference is between a standard Valk alternator and a "high output" alternator. I can only tell you the difference between the standard alternator and the H.O. alternator I purchased from M.A.R.S. (Ken Hemming). The standard Valk alternator puts out about 45 amps (546 watts) at approx. 3,000 rpms. My H.O. alternator from M.A.R.S. puts out about 74 amps (890 watts). The only downside to the H.O. alternator from M.A.R.S. is that it requires an idle rpm of just over 1,000 to get a charge at idle. I have this alternator on a Valk with a sidecar attached, along with a few additional lights, other accessories, and radio intercom system. I keep my Valk's idle at about 1,100 rpms and am happy with the results.
