Is A One-Wire Alternator The Right Choice For Your Hot Rod?

When your classic Chevy was driven off the dealer’s lot when it was new, chances are, it delivered years of reliable service. Back then, cars were much simpler and didn’t have the electronic demands found in today’s hot rods. That means there were fewer things that could go wrong. Back then, the limited output delivered by the alternator was more than enough to sustain the power needed to run the engine with the headlights on. Now, however, enthusiasts are installing accessories like high-amp stereos, electronic ignitions, and fuel injection in the classics we strive to improve.

The folks at Tuff Stuff Performance have a thorough understanding of the electrical needs required when adding many of the electrical upgrades that have been installed in our hot rods. To help enthusiasts, Tuff Stuff has developed a myriad of alternators with varying designs to help all enthusiasts. One of those design elements is a one-wire alternator.

one wire alternator

When adding a one-wire alternator, you can eliminate the two-wire plug used to connect the to a switched power source and the voltage-sensing wire.

Unfortunately, we get a lot of emails about one-wire alternator installation, and we decided to reach out to the folks at Tuff Stuff to see if we could help clear away some of the confusion.

The most frequently encountered concern by enthusiasts is rooted in actual fact. “Is it true that one wire alternators don’t charge at idle”? At one time, one-wire alternators did have issues with this scenario. After a car was started, the driver would need to “blip” the throttle to excite the alternator in order to make it “turn on.” However, the folks at Tuff Stuff have developed internal components in its alternators that will keep your battery charged, even when the engine is in low-RPM situations. We’re told that no other manufacturer in the industry has been able to produce more amps at low RPM than Tuff Stuff.

As the descriptive name implies, connecting a one-wire alternator to your ride is as easy as running a single charge wire from the battery terminal on the alternator to the positive terminal on the battery. With the Tuff Stuff units, no other connection is necessary. Tuff Stuff does say that you can also consider running the wire to the starter solenoid’s main lug if you wish to hide the charge wire for a cleaner look. For many classic Chevy’s, this is how it was done at the factory.

While the connections are simple, care needs to be taken to ensure the wire used is of the proper gauge and that it is routed away from moving parts and other items like headers and exhaust. If you are thinking about using the factory alternator’s “hot” wire during an alternator upgrade, you might want to reconsider that notion. Remember, the factory alternator was only supplying a small number of amperes, and your new alternator delivers more juice.

If your vehicle was originally equipped with a dash-mounted ALT light, sometimes it will be necessary to connect the voltage-sensing wire. To do this, remove Tuff Stuff’s black, rubber regulator cover and plug in your existing two spade plug. This procedure can be performed when installing alternator models 7127, 7139, and 7140.

Tuff Stuff generally recommends using an 8-gauge wire for its 100-amp alternators and a step up to a 6-gauge charge wire if the battery is in the trunk. Also, a 140-amp unit should use a 6-gauge wire and a step up 4-gauge when routing to the trunk. When upgrading to the big 200-amp unit, a 4-gauge or 2-gauge wire is recommended.

If you are wondering when to use a one-wire alternator, look at it like this: a one-wire alternator will simplify your build, especially if you are starting a project from scratch. In this case, there is no need to install the messy wiring harness from an externally mounted regulator, or the voltage-sensing and switched-power wires like is used from the factory. In many upgrade instances (installing a new alternator to replace an older unit), you can actually remove your existing external regulator and harness and replace it with one wire.

one wire alternator

During a recent alternator upgrade in our C10, we needed to increase the size of our charge wire, Although it might not look like much of a change, the larger diameter will be noticeable while the alternator is working.

One thing to keep in mind is, if your vehicle was originally equipped with a dash-mounted ALT light, in some GM applications, it will be necessary to remove Tuff Stuff’s black, rubber regulator cover and plug in your existing two spade plug. This procedure can be performed when installing models 7127, 7139, and 7140.

Adding an alternator that will keep your electrical accessories properly juiced is a great upgrade. If you are tired of your headlights going dim each time a turn signal blinks, you know I’m right. If you are going to upgrade, Tuff Stuff Performance would like you to know that its alternators can be utilized in both factory and one-wire configurations. What are you waiting for?

More Sources

About the author

Randy Bolig

Randy Bolig has been working on cars and has been involved in the hobby ever since he bought his first car when he was only 14 years old. His passion for performance got him noticed by many locals, and he began helping them modify their vehicles.
Read My Articles

Hardcore Chevys in your Inbox.

Build your own custom newsletter with the content you love from Chevy Hardcore, directly to your inbox, absolutely FREE!

Free WordPress Themes
Chevy Hardcore NEWSLETTER - SIGN UP FREE!

We will safeguard your e-mail and only send content you request.

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

We'll send you the most interesting Chevy Hardcore articles, news, car features, and videos every week.

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

Chevy Hardcore NEWSLETTER - SIGN UP FREE!

We will safeguard your e-mail and only send content you request.

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...



Hot Rods & Muscle Cars

Corvette Enthusiasts

Street Rods

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

  • Hot Rods & Muscle Cars
  • Corvette Enthusiasts
  • Street Rods

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

Thank you for your subscription.

Thank you for your subscription.

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

Thank you for your subscription.

Thank you for your subscription.

Loading