[stellar]

1st your question then the docs' diagnosis. With a conventional (OE or OE style replacement reg) the alt will not charge without the sense wire connected. So from the info given I suspect you have an alt using a one wire reg the (self exciting) type that will allow the light function to work. With this type of reg the sense wire isn't necessary to charge. I also suspect you have a 10 SI alt that has been converted to 140 amps by changing the stator. With this set up the alt will charge at a lower amount at low RPM than even a stock 63 amp alt. It will not put out the higher amps until it is running at a high RPM. Volts will also be lower. A stock alt will charge well over 16 volts with the bat disconnected, and you only had 14.56. Lucky you because damage can occur to electronics when disconnecting the bat with car running. It is not a good thing to do. I think you would have better performance using a stock 12SI 94 amp alt.

[guccieng]

it's a 12si three-wire powermaster, btw. i just got off the phone with powermaster and gave them the full scoop. they think the internals are fine, but since the voltage dropped with such a light load (18 amps), they think it's a grounding issue. i'm going to sand down the internal case attaching points to remove the powdercoating. the brackets are also painted or powdercoated, so they recommended running a ground strap from the frame straight to the case. hopefully that will do the trick.

[guccieng]

success! i cleaned up the alt innards/case and reassembled it. added a gound strap to the bottom mounting hole after sanding down to bare aluminum and ran it to the engine/frame mount and sanded it to bare steel. started like a champ, thanks to the new battery, and gave 14.56 volts with the headlights on bright. the fan kicked on at 195 degrees and it stayed at 14.32 (w/brights on). what do they say? 90% of all electrical issues are grounds? lesson learned: paint and powdercoat might be pretty, but can hurt your electrical performance. thanks to all who replied!