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Big 3 Power Upgrade Kits for Car Audio

Car engine in engine compartment with hood up, as extra batteries ready for the big three audio wire upgrade.

So you heard about the Big 3?

Boost voltage flow and eliminate power loss with a Big 3 Power Upgrade Kit – the ultimate wiring upgrade for serious car audio builds.

Designed to handle high current demands from aftermarket amplifiers, subwoofers, and high-output alternators, these kits upgrade three critical connections:

  • Alternator to Battery
  • Battery to Chassis Ground
  • Engine Block to Chassis Ground

Choose from oxygen-free copper (OFC) or copper-clad aluminum (CCA) wiring in multiple gauge options to match your system's needs. Whether you’re daily driving or chasing SPL records, our Big 3 kits:

Available in 1/0 AWG, 4 AWG, and custom lengths

Heat-resistant insulation for under-hood use

Pre-terminated with high-quality ring terminals

Compatible with high-output alternators and batteries

Don’t let weak wiring hold you back—upgrade your power delivery and unleash the full potential of your car audio system.

Shop Big Jeff’s Big 3 Wiring Kits

Q & A

Frequently Asked Questions

⚡ What Is a Big 3 Wiring Upgrade Kit?

If you're pushing serious power through your car audio system, your factory wiring isn't gonna cut it. The Big 3 Wiring Upgrade is all about strengthening your vehicle’s electrical foundation by replacing three key wires:

  • Battery ground to chassis
  • Engine ground to chassis
  • Alternator positive to battery

This improves current flow, reduces voltage drops, and keeps your amps and lights from cutting out when the bass hits. If you're running a high-output alternator or multiple amps, this upgrade is a must.


🤔 Are Big 3 Upgrade Kits the same as Amp Install Kits?

Nope, totally different beasts.

Big 3 Upgrade Kits are all about giving your electrical system a serious boost—upgrading the three key wires:

  • Battery ground to chassis
  • Engine ground to chassis
  • Alternator positive to battery

This helps stabilize voltage, reduce strain, and prevent power drop-offs when you're pushing serious wattage. Basically, it beefs up your system’s foundation so your amps and subs don’t suffer.

An Amplifier Install Kit, on the other hand, includes:

  • Power & ground wires (usually longer runs to reach your amp)
  • RCA cables
  • Speaker wire
  • Remote turn-on wire
  • Fuse holder & ring terminals

So if you're wiring up an amp for the first time, grab an Amp Install Kit.

If you already have gear installed and your system needs more stable voltage? That’s where the Big 3 comes in.

🛒 Need Amp Kits too? Check out our Amplifier Wiring Kits

🚗 Why Upgrade Your Vehicle's Electrical System?

Because your car's stock wiring was designed to run factory speakers—not upgraded subwoofers, multi-channel amps, DSPs, underglow, and whatever else you’ve got going.

The Big 3:

✅ Reduces resistance
✅ Increases power flow
✅ Prevents headlight dimming
✅ Helps alternators perform better
✅ Protects your amps from voltage drops

It’s cheap insurance for the stuff you already spent money on.

🧰 What’s in a Big Jeff Big 3 Kit?

Every kit is slightly different depending on the brand and spec, but most include:

  • 1/0 or 4 AWG OFC power & ground wire
  • Fuse holder & fuse
  • Heat shrink tubing
  • Ring terminals
  • Wire loom
  • Zip ties

We carry top brands like Audiopipe, Full Tilt Audio, and DS18—all quality-tested and daily-driver approved.

🛠️ Do I really need the Big 3?

If you’re running aftermarket amps and pushing serious power—yes. If you’re still rocking factory sound with no big draw? Probably not. But once you start throwing down 1000W+ RMS, don’t be surprised if your lights dim or your voltage drops. Big 3 helps fix that.

⚡ OFC vs CCA – Which is better?

OFC (Oxygen-Free Copper) is the premium option:

  • Better conductivity
  • Lower resistance
  • More durable long-term

CCA (Copper-Clad Aluminum) is more affordable but not as efficient. If you’re serious about performance and running high wattage, go with OFC.