If you have a classic car that needs an alternator, it is important to connect it correctly. Otherwise, you may end up damaging the alternator or your battery. Fortunately, there are a few simple things you can do to make sure your alternator is connected properly.
1.Connect a large power lead from the output terminal on the alternator directly to the positive post on your battery. This connection can be made with a 6 or 8 AWG power wire. It is best to use a 6 AWG wire because it is a little thicker and more durable than an 8 AWG wire. This will provide enough power to run your battery without causing damage.
2.Connect the exciter plug to your alternator using the proper type of connector. This connector should be in the rear of your alternator, and it should snap into place. It will have two pins on it, one is red and the other is black. You can buy this connector in the parts department of your local auto store or at a specialty store that sells automotive equipment and accessories.
3.Mount your new alternator to the engine with the belt over the pulley and tighten it until you have about 1″ to 1 1/2″ of belt deflection. Depending on the original set up, you may need to purchase a new belt for this.
4.Connect the alternator to the electrical system with a pigtail or harness that connects the alternator to the wiring in your engine. This is usually easy if the harness has the right connectors and is compatible with your alternator.
5.Tune the alternator’s speed to match the vehicle’s amperage requirements at low speeds or idle. Most alternators have an output curve that rises abruptly at low speeds and level off at higher speeds. Some curves rise more slowly and peak at a higher point, and are designed to produce more output at low speed.
6.Check the voltage with a quality volt meter to make sure it is above 12.6 volts. If it is lower than this, your system is probably not charging your battery as well as it should be.
7.Connect an amp meter to the output stud on the alternator, if you have one. If not, cut a piece of the wire and attach it to the other end of the amp meter. This will allow you to check your battery and the charge on the alternator with an amp meter.
8.Check that the alternator is grounded to the negative side of your battery. This is done to protect your battery and the internal regulator on your alternator from damage.
If you are upgrading your alternator to a higher output version, connect the amp meter to the other terminal on your alternator instead of to the stud. The amp meter will allow you to see how much the alternator is charging your battery, and it will also be easier to tune your alternator for maximum output at low speeds or idle.