How to Wire My Alternator to My Battery

Automotive alternators supply the automotive electrical system with the electrical energy needed to operate an automobile. Without the alternator, an automobile can only operate on battery power for a few minutes.


One of the functions an alternator performs is to recharge the battery. To do this, an alternator must be connected in a parallel circuit to the battery.

Things You'll Need

  • Automobile
  • Automotive alternator with internal regulator circuit
  • Alternator-to-battery wire
  • Automotive battery
  • Automotive battery relay switch
  • Alternator ground wire
  • Adjustable wrench
  • Loosen and remove the alternator battery terminal retaining nut. Place the ring terminal on the alternator-to- battery wire over the alternator battery terminal bolt.

  • Replace the retaining nut. Tighten the nut to a snug fit. Route the alternator-to-battery wire around the automobile engine so that the wire does not come into physical contact with the engine housing.

  • Attach the free end of the alternator-to-battery wire to the "Alternator" terminal on the relay switch.

  • Loosen the retaining nut on the alternator ground terminal. Place the ring terminal on the alternator ground wire over the terminal, and replace the retaining nut. Tighten the nut to a snug fit.

  • Attach the alternator ground wire to a point on the vehicle chassis, such as the battery ground wire bolt.