A dumb electrical question (please educate me)

[vettestr]

The headlights were a great visual for the fluctuations in demand and supply voltage. I have the typical voltage demands on my car as most of you ....puller cooling fans, headlights, running lights and ignition. In addition to the demands of MSD ignition I am running aftermarket fuel injection.

The sages or drop in system voltage at idle was causing my Holley injection CPU or control unit to freak out if voltage dropped below about 13VDC. I had my 100 amp Alternator hot rodded at my local rebuilder to perform better or supply amperage at a lower RPM. I don't know what he did internal but he also installed a smaller pulley so it now supplies amps at 600 engine RPM. My engine idles at about 950 and will lope to maybe 800 now and then but is well above 600 turn on point.

I installed a second battery so I have plenty of amps and does not load the demand at idle now. My lights stay bright and ignition as well as injection CPU purrs right along. The grounds and positive connections need to be sound of course but a second battery and hot rodded alt. made all the difference for me.