Electrical 3g Alt Voltage

Discussion in 'Fox 5.0 Mustang Tech' started by Casey2552, Sep 26, 2013.

  1. After reading a previous post , and commenting I thaught about how I'm runnin the 4 gauge wire , I had a kicker 4 g wire with 150 amp kicker fuse block, I installed and everything charging great but I'm wondering will it over charge alt will know when to stop charging or is that what the fuse able link does , I do have stock cable from the Taurus I got alt and really think I should use it , but like how fuse block looks here's a pic I also feel that the stock line from Taurus is safer

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  2. I've been running a 150A fusible link from a heavy truck shop in my car for a couple of years now with my 150A 3G with zero issues. I ran U/D pulleys, electric fan and a fairly healthy Alpine stereo system and thus far, no issues.

    I get a bit of a dip in the dummy gauge when the fan kicks on when idling in traffic, but it recovers pretty quickly.

    I wouldn't sweat it.
  3. You have to fuse the system based on the lowest rated component. In this situation, it's the wire. Depending on the wire quality, and the lenght of the run and heat the system sees, a 4G wire is really only rated to around 100A. Shorter runs in cooler locations can take more amps than long runs that pass by large sources of heat.

    So your fuse should really be based on what the wire can handle. You rarely will see over 100A of current draw on your alternator unless you are powering some serious electrical components. But for your average Mustang even with an E-fan, you will probably be in the range of 75-85A, for which the OEM alt was slightly undersized for. So even fuse protection for 100A should be enough.

    Your actual voltage output should be around 12.5V at idle, and 14.4V above idle (while driving) a voltage regulator will maintain this voltage, so no need to worry about overcharging. You just need to be sure the alternator pulley is such that you maintain at least 12V at idle, and a small blip of the throttle over idle creates 14.4V.
  4. I used a 125 Amp Fuse in my system when I did the 3G conversion.