What Is the Big 3 Upgrade Kit?




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Improving the audio system in your vehicle enhances your overall music experience. However, such upgrades draw heavily on your vehicle’s electrical system, causing some underperformance or malfunction.

One of the recommended solutions for improving the performance of car audio is the Big 3 Upgrade kit. But what is the Big 3 upgrade kit?

The Big 3 Upgrade Kit is an inexpensive setup added to three main locations within a vehicle’s wiring. When properly installed, it allows current to flow more freely and helps the factory alternator reach its full potential. The installation deals with all signs of an overloaded electrical unit.

Tip: The Big 3 Upgrade kit is pretty universal, so you don’t need different options for different vehicles.

When buying the kit, go for wires similar in size to the one powering your amps. You may also need to change your battery terminals to accommodate the additional cables.

I have listed below the additional parts you will need for the correct Big 3 installation. All items are available on Amazon, so if you are going to install the system by yourself, click the links below and check the most recent prices:

Sky High Oversized 4 Gauge AWG Big 3 Upgrade Blue/Black Electrical Wiring Kit: Most vehicles go with this wiring kit due to its size. The size means it can fit into most installations easily.

InstallGear 0/2/4 Gauge AWG In-Line ANL Fuse Holder: The unit comes with a 250 Amp Fuse in the box. The durable high temperature based and high conductive finish makes it stand out.

SUNMORN Battery Terminal Connector: You’ll need two of these durable and easy-to-install battery connectors for each battery terminal.

In this article, I will cover all you need to know about the Big 3 Upgrade kit, the benefits, and how you can install it without professional help.

The Big 3 Upgrade Kit: An Overview

As an audiophile always looking for the most powerful listening experience, you’ve likely added an audio system that delivers 3000+ watts of power to your vehicle.

Unfortunately, the average vehicle manufacturers didn’t account for your tougher than average music demands.

Your vehicle’s wiring, alternator, and charging system return path were designed to power the factory-fitted electrical components, including your sound system. These systems are designed to accommodate all standard features, even under extreme use or poor weather conditions.

Adding a powerful audio system to the mix means that all this equipment will need additional current to perform.

In such a situation, you’ll witness a significant voltage drop around your power amps’ B+ and B- terminals. You’ll also notice other signs like dimming lights (while listening to music), slower window motors, etc.

If you ignore these signs long enough, you’ll end up with a damaged sound system, a dead battery, and, in some cases, a damaged alternator. Unfortunately, it’s not uncommon for all three to happen. 

GP Car Audio Big 3 UPGRADE wiring Kit OFHC TRUE 1/0 AWG GAUGE RED and BLACK

The Big 3 Upgrade kit prevents these problems and allows you to enjoy your new sound system, and when installed properly, it will improve the efficiency of your vehicle’s current management.

You may be wondering why the alternator is important in this conversation if the battery holds all the power.

In reality, the battery is the primary source of power to start the engine or run the electronics in the vehicle when the engine isn’t running. Once the engine is running, the vehicle alternator will generate a higher voltage than the battery, making it just as important as your battery.

What Are the Benefits of Using the Big 3 Upgrade Kit?

There are two main advantages of using the Big 3 Upgrade kit:

  • First, it optimizes your alternator’s performance.
  • Second, it ensures a low resistance path between your audio and charging systems.

Remember, the Big 3 Upgrade kit won’t increase your alternator’s voltage or current capability.

What Does the Big 3 Upgrade Consist Of?

The three connections completed in the Big 3 upgrade include the following:

The Alternator to Battery Positive Wire

As you’ve seen above, the alternator is the primary source of power when the engine is running. Therefore, it’s a good idea to ensure that the wire connecting it to the rest of the electrical system is large enough to handle the current needs of your electronics.

The factory-fitted option is usually powerful enough to handle all electronics. However, as I mentioned above, any wild alterations to the electronic configuration automatically strain the alternator. 

So, this is why the wire linking the battery positive terminal to the alternator charging post is one of the targets of the Big 3 Upgrade.

The Battery Negative to Chassis Wire

A DC circuit isn’t complete without a return path to the ground at the source. To ground an amplifier, you have to connect a large gauge wire from the amp’s negative terminal to the vehicle’s chassis. 

However, the vehicle’s chassis isn’t your electrical system’s ground. It’s only the conduit to carry current to the real ground system.

The current channeled to the vehicle chassis, and the various ground connections go to your battery’s negative terminal through a factory-fitted wire. The wire is the bridge between your vehicle’s chassis and the battery negative terminal.

At around 6-8 AWG in size, the factory-fitted option is usually too small to match the wire you’ve added to carry current from your amplifier. Thus, it’s the second target location for the Big 3 Upgrade.

Engine Ground to Chassis Wire

The third target of the Big 3 Upgrade is your alternator’s return path to the ground. The alternator’s case is its ground terminal. 

A factory wire connecting the engine to the chassis links the case to the rest of your vehicle’s ground system. Just like the other wires, it’s often too small to carry an oversized load. 

Do I Need the Big 3 Upgrade Kit?

You need the Big 3 Upgrade kit if you’ve substantially increased demand on your vehicle’s electrical system. You may also consider getting the kit if you see the signs of heavy demand on your vehicle’s electrical system, even when you haven’t made any changes.

Can I Install the Big 3 Upgrade Myself?

You can install the Big 3 Upgrade if you have all the tools needed for the job and can follow the laid-out instructions.

However, if you feel like you’re unsure of what to do, don’t hesitate to drive to a repair shop. Most shop attendants should be able to complete the upgrade in minutes. 

Taking your car to a repair shop will invariably increase the cost of the upgrade as you’ll have to pay the labor charge in addition to any markups on the components required. You can keep the cost down by buying the Big 3 Upgrade kit and taking it along.

How to Install the Big 3 Upgrade Kit?

To install the big 3 Upgrade Kit, follow these simple steps below:

  1. Get parts and supplies.
  2. Disconnect the battery and discharge capacitors.
  3. Upgrade the battery negative to chassis wire.
  4. Upgrade the ground to chassis wire.
  5. Upgrade the alternator to battery positive wire.
  6. Complete the connection.
  7. Get Parts and Supplies

As far as supplies go, you probably have everything you need already, but if not, all items that I use are listed below:

Disconnect the Battery and Discharge Capacitors

With parts and supplies in place, the next step is to disconnect your car battery. Remove the negative terminal first before removing the positive terminal. 

Discharge the capacitors and disconnect any additional batteries you may have installed in the vehicle. Here’s a guide on how to discharge capacitors.

With the batteries disconnected and capacitors discharged, you now have a safe environment for the main part of the upgrade.

You’ll work on the three connection points we’ve mentioned above. You can do them in any order you like and still complete the upgrade successfully. So, the following steps can be interchanged.

Upgrade the Battery Negative to Chassis Wire

The first step with this wire is to choose the attachment location on the chassis.

You can work with the exact bolt location as the factory connection. Alternatively, you can drill a new hole for a new bolt location if you have the tool. Whichever option you choose, clean the area first.

Use a degreaser for the cleaning, and then scrape off paint in the area to unearth plain metal to connect the ground wire. The degreaser won’t remove paint, so you’ll need a wire brush attached to a drill or sandpaper.

With the attachment location ready, measure out the length of the wire required to complete the connection. Next, attach a ring terminal on the end of the wire going to the chassis. 

After you’ve connected the wire to your chosen ground location on the chassis, apply dielectric grease to the metal surroundings of the ring terminal, as well as directly on the terminal. The grease will prevent rust from forming.

Upgrade the Ground to Chassis Wire

The approach here is similar to what we talked about for the battery negative to chassis wire. You can install the wire at the factory location, and you can also create a new location. 

Clean and prepare the spot as described above. One end of the wire will go to the factory-designated engine ground location.

After you’ve worked out where to connect your wires, measure the length of the wire required and attach a ring terminal to both extremes.

Clean the engine ground location with a cleaner and strong brush to ensure a solid connection to the metal. Once done, connect both ends of the wire.

Upgrade the Alternator to Battery Positive Wire

The first step here is to determine a route for your new wire. You can follow the path of the existing wire or create a new one depending on what’s most practical for your car.

If you choose to create a new path, you need to keep the wire away from moving parts like fans and belts. You also need to avoid all parts that get hot when the engine starts running, such as the engine block or exhaust manifold.

Your chosen pathway should also allow you to have an inline fuse holder at most 6-inches away from the alternator connection. The arrangement will ensure the wire doesn’t start a fire in case of a short to ground.

Make sure you’re installing a fuse that is the same ampacity as the wire you’ll install. The fuse should never be larger than your alternator’s rated output current.

After you’ve settled on a route for the wire, measure out the wire length you need and add a ring terminal to the wire end going to the alternator.

When connecting the new wire to your alternator’s charging port, you can elect to use both the factory-fitted wire and the new one you’ve installed. You can also choose to use the new wire alone.

Pay attention to the ring terminal. No part of the terminal should touch the alternator case or other ground locations to avoid a short circuit. So, it’s best to hold off on connecting the battery end of the wire to the battery if you’ve used a ring terminal on it.

Complete the Connection

With all your wires positioned, it’s time to hook everything up to the battery. Begin with the positive battery terminal connections and move to the negative ones.

Look over your installation one more time to ensure the wires are safe from hot surfaces and any moving parts. Tie off the long wires every five inches using zip ties.

For the final confirmation, use a digital multimeter to measure the resistance. You can do this by measuring the resistance between the engine ground location and the negative battery terminal. 

Confirm that resistance is less than one ohm and repeat the process with the alternator charging post and the battery terminal.

Once everything checks out, you can proceed to enjoy your sound installation without worrying about the strain on your vehicle’s electrical system.

Here’s a video you can work with if you need visual help installing the Big 3 Upgrade kit.

Final Thoughts

Installing the Big 3 Upgrade kit is the perfect way to improve the performance of your vehicle’s electrical system. In addition, a successful installation improves the handling capacity of your vehicle’s electrical architecture. 

Once completed, you can upgrade your audio system by adding components more powerful than the factory-fitted option.

With the upgrade completed, you can add extra batteries, alternators, or capacitors to your vehicle to make the electric system more robust.