I have a 1969 mustang and just replaced the original alt. with a 100 amp 1-wire alt. The instructions are pretty poor and i was wondering if you just jhave to connect the 1-wire directly to the battery terminal, and whether or not you should reconnect the ground to the housing. How can i test to see if it is putting out enough power. I have also heard that with the 1-wire alt. you have to have the car reving at over 1800 in order for it to charge at all. Is this true?
Thanks alot
Matt

 

The self exiting or "one wire" alternator hooks to the battery. In order to get the VR to turn on, all you have to do is rev the engine at start up. It then stays on at all RPM's until your turn the engine off.

 

is there a benifit to having a self exiting alt?

 

Self Exciting, not self exiting.

Self-Exciting Alternator:
Is an alternator that uses a special voltage regulator that doesn't need an ignition wire to activate it.
This type alternator only requires a battery wire hooked to it. The voltage regulator contains
circuitry that uses the residual magnetism in the alternators fields to determine when
to turn the alternator on. The regulator does this by sensing the RPM the alternator is turning,
when it gets to a certain rpm the voltage regulator "turns on". Typically you start
the vehicle, rev the motor slightly then alternator starts charging. This type alternator is
commonly used on custom cars & trucks, tractors and other non standard applications when
wiring is a factor. In choosing this type alternator you must consider, do you want
to rev your motor slightly to get the alternator to turn on. Also when using the self-exciting
alternator on tractors or other slow turning motors does the engine
have enough RPM's to start the alternator charging. This can be overcome by using a smaller
pulley or by adding an ignition wire.


One-wire Alternator:
Is another name for the Self-Exciting Alternator mentioned above. You only need connect the battery wire (one-wire).


Two-wire Alternator:
Most standard and all self-exciting regulator alternators will work using the two wire setup. Two wire means that you use the battery wire and an ignition wire to activate the alternator. With this setup the alternator starts charging as soon as the engine is running


Three-wire Alternator:
This setup uses a battery wire, ignition/warning light wire and voltage sensing wire, Three wires.

 

Thank you for this info. What would be a good ignition wire? Do you mean a wire that is activated from the ignition switch? Do you think that the alternator should do a good job when cruising around town at low speeds?
Thanks alot
Matt

 

The ignition wire he is referring to is a wire that is excited when the ignition is turned on.

I run a 1-wire alternator with a 5.5" crank pulley. I didn't really know about the need to have the alternator turn a certain rpm first, but mine works very well. I bought mine from Jeg's. The only thing I don't really care for is how deep it is. I had to grind down a bracket mounting bolt so the alternator would clear. I don't use any special ground wire.

Be sure to use good wires (Jeg's also has a wiring kit). I have an Optima battery that pulls a lot of power when slightly discharged and even 2 gauge wire gets warm (I have a 120amp breaker installed from Jeg's, and it will trip if the battery is around 11.5 volts...still enough power to start).