- Battery positive (+) to alternator - From the positive terminal on your battery to the alternator positive (+) post
- Engine block to chassis ground - From engine block to chasis. This is to strengthen the ground.
- Battery ground (-) to chassis ground - From the negative terminal on your battery to your car's chassis.
I recommend using 1/0 gauge wire. You could use 4 gauge wire if that's all you have laying around, but you might as well use 1/0 the first time so you won't have to go back if you decide to upgrade your system later on down the road. The wire I used was Knu Konceptz 1/0 Kollosus Kable You will also need 1/0 ring terminals to terminate the ends of the wire.
Before you do anything, make sure to be safe. Disconnect the wire from the negative terminal of your battery before you begin. This makes an incomplete circuit and keeps you safe from sustaining electrical injuries.
First, measure a length of wire to go from your battery positive (+) terminal to your alternator. Make sure to leave a little bit of slack, around 6 inches, so you'll be able to position the cable freely. Terminate the ends of the cable with ring terminals, then connect the wire from battery positive (+) terminal to your alternator. There may be a plastic tab on the alternator post. If there is, go ahead and break it off; it's what I had to do. If you don't remove the plastic tab, you won't be able to remove the nut off of the terminal post.
Adding a fuse to go in between the battery positive (+) and the alternator is highly recommended, but not necessary. There is a small chance that the wire will come lose and short out, but it's a chance some people do not want to take. On the contrary, I have had no problems in the 2 years I've had the big 3 installed while running an unfused wire.
The next step is to run a wire from your engine block to your car's chassis. This step may be difficult because you may have a hard time finding a place on the engine block to attach your wire. Look for a non-essential bolt; do not use a bolt that holds fluids back.
From there, you then need to attach the other end of the wire to your chassis ground location. This ground can be anywhere on your car's chassis/frame, but make sure that you have metal-to-metal contact with the terminal and your ground location. A good start is to follow your stock ground wire back to its grounding location. If there is paint on the ground location you have chosen, you must sand it off until it is bare metal to ensure minimal electrical resistance.
Lastly, the final step is to run a wire from your battery's ground (-) terminal to the ground location on the chassis. Measure the wire and be sure to leave a little slack in case you need it. Then terminate the ends with ring terminals and attach one end to the negative terminal and the other to your grounding location on your chassis (as seen above).
Once you have made the new, beefier battery ground, you can cut off, disconnect, do whatever you want to the stock ground wire because it is not needed anymore. When you think you're finished, go ahead and double check all of your connections making sure that they are snug and tight.
That's it! The "Big 3" is now finished. You should notice a difference in voltage when playing your system at max volume. Before I did this upgrade, my voltage was at about 10v under heavy load. After doing the "Big 3" upgrade, my voltage under heavy load was stabilized at about 11v. Quite a large difference for how much you spent on the wire and terminals. That's why the "Big 3" is considered the first electrical upgrade you should do to ensure consistent power to your amplifiers.
