1/0 AWG Big 3 Upgrade Kit for Top Post Batteries


The most popular car audio upgrade in the world: the Big 3! We’ve been doing this LONG before it even had a name (think 1990 or so), so it only made sense that we’d build and offer the best kit money can buy!

Our 1/0 AWG Big 3 Upgrade Kits are suitable for alternators making up to 300A of output.

To determine which length kit you need, measure the distance from the alternator output stud to the battery positive terminal taking into account a nice smooth run for the cable. For example, if you measure 3 feet 4 inches, you will need a 4 foot kit.



Read our white paper, The Truth about the Big 3 Upgrade so you can learn the real benefit and understand exactly why we do it the way we do it.

“All top notch and worth every penny. You will not be disappointed.” – David B., Orlando, FL

Our Big 3 Upgrade Kits address the following:

  • Upgrade the charge lead from the alternator output stud to the battery
  • Upgrade the return path between the alternator and vehicle ground
  • Upgrade the return path between the battery negative (-) and the vehicle ground
  • Provide a low resistance return path for high current amplifiers

We offer Big 3 Upgrade Kits for Top Post Batteries and Side Post Batteries. If you own a vehicle with a rear mounted battery, we can custom build a kit to suit you.


Option 1: Fuse the Charge Lead

Most OEM charge leads have a fusible link on them. Its purpose is to protect on-board electronics in the event that the regulator fails and causes “voltage run-away.” Although this is quite uncommon, fusing the charge lead included in any of our kits provides the same protection for your larger than stock alternator.

5 reviews for 1/0 AWG Big 3 Upgrade Kit for Top Post Batteries

  1. 5 out of 5

    Grant (verified owner)

    Outstanding quality and complete! Couldn’t be happier. I’ve improved wiring on vehicles in the past but absolutely no comparison to this. I did the grounding kit as well. I’ll soon be starting on my next project car and it too will be running your big 3 and grounding kits.

  2. 5 out of 5

    Scott Turner (verified owner)

    Quality components and easy to follow directions.

  3. 5 out of 5

    Nathan (verified owner)

    Great product, I have not had any issues so far.

  4. 5 out of 5

    Dan Ellison (verified owner)

    Ordered this kit for my 06 Jeep TJ Rubicon the quality of the product is extremely awesome installation instructions are very clear all Hardware you you need is included time from order till delivery was very Swift extremely satisfied with purchase

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