1 wire alternators

Wether or not you use a high amp alt should depend on your application. Electric fans can draw up to 50 amps or more: http://store.summitracing.com/partd...924500+4294839058+4294838842+115&autoview=sku

Then add in the following:

Headlights/tailights/turn signals
Electric fuel pump
Electric water pump
Defog/heater blower motor/Air conditioning
Ignition


You can see someone could get into trouble fast on a hot foggy evening driving home from a car show/road trip and I'm not even adding in power windows, power seats, big stereo, etc. If we're talking trucks, then we have off-road lights, winches, trailer electrical load, etc.

A race car or original resto is another matter altogether. A big alt isn't needed or required, but you would still need to add all of your draws together and make sure your whatever alt you use is adequate, or end up looking like the nimrods on Pinks screaming for a jump.

Keep in mind that a one wire alt needs the rpm blipped up to about 1500 rpm or so to switch on, and they also sense voltage at the alt vs. the harness or switched power lug at the fuse box like you can wire an externally regulated alt to do.

A high amp alt can melt a harness if the 10 ga. wire from the alternator is not changed out for a wire of sufficient current handling capacity and the current draw exceeds the capability of that wire. Oh yeah, don't even think of running a high amp alt through the stock ammeter, get a voltmeter.