SF Alternator Upgraded Wire Size?

[eschaider]

What Patrick is saying about safety, and you should read safety as preventing fires that burn your car to the ground, is spot on! The cost and effort to install a voltmeter is nothing compared to what you will experience after a fire. Even Detroit quit using amperage gauges for exactly that reason — fire!

With respect to how much is too much amperage, that depends on your personal power budget for your car. You have to figure it out. My SPF currently has a 240 amp unit, and my power budget has me looking for a 340 amp unit that I can fit in where my current 240 is living.

There is no problem with the SPF wiring handling this. You are charging the battery. The alternator wire goes to the hot post on the starter solenoid, not a cigarette lighter. The various power consumers in your car may or may not require wiring upgrades depending on their individual power consumption.

My fuel pumps running flat out consume 45 amps and have a 10 gauge wire supplying power. My Mk VIII fan used to draw 75 amps on an initial cold start. It used 8 gauge wire. I went to a Focus variable speed fan controller with a soft start feature and went back to normal proletariate wiring sizes.

These cars are custom-built toys architected by their owners — that means guys like us. Just take the time to do it right and, this is really important, if you don't know how to engineer what you are fiddling with buy the expertise from a firm or person who does. It is much cheaper than the whoops that is waiting in ambush for you, just around the corner.