Wire Fire


I installed a stereo amp and electric fan in my ’73 Challenger which, combined, requires more juice from the alternator. I’ve installed a 130-amp alternator but wiring has me stumped. I would like to run 4 ga. wire from alternator to factory ammeter and another wire back to starter relay with a fusible link. Can the ammeter take it? Also do I leave the factory 10 ga. charge wire at the alternator attached with new 4 ga. wire to power accessories or leave it off? If off, how do all the accessories obtain power?

You are at serious risk of setting the whole car on fire—soon!

Here’s the basics:

  • Every wire in the charging system must be upgraded to 4 gauge, and the fus- ible link must be swapped to 6 gauge, or a 125 Ampere maxifuse installed. The primary charging current flow is
  • The charging current must no longer pass through the firewall. Neither the bulkhead connector, nor the ammeter, can handle anything even close to 130 A.
  • The OEM 12-gauge red and black wires should be connected together on both sides of the bulkhead. Inside the car, you can just nut/bolt the ammeter wires together, insulate well. The OEM underdash wiring (the 12-gauge wires) must be protected by a 40A fuse (at the bulkhead connector).
  • Convert to a voltmeter wired to igni- tion-on +12V. The ammeter itself must go away (disconnected, or converted to voltmeter by Auto Instrument Spe- cialties, 3 etc.)
  • Be sure that the voltage regulator works correctly and is temperature compensated. Battery explosions are not fun.
Smoke from a Challenger should be from the rear tires. Only. Underhood, smoke from electrical sources is not good, usually results in (or from) fire.
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