While every system uses different components, there is one area that is often overlooked, the wiring. I am not talking about the power and ground wire that runs to the amps or the speaker wires, I am referring to the charging system. Before adding anything else, upgrading these wires is critical for optimum performance. Most enthusiasts call it the “Big Three”, and it will do wonders for your system’s performance.
The big three refers to the wiring for the charging system; battery to ground (frame or body), alternator to battery, and engine to frame (or body). Contrary to popular belief, electricity flows from negative to positive, not the other way around. The negative cable is just as important as the positive cable; the methodology of transferring that power is just different. Most cars use negative ground systems, and all car audio equipment is designed for negative ground systems. This is where the negative pole of the battery ties to the vehicle’s metal body or frame. The positive pole of the battery is run to each component with individual wires, so each component gets the proper gauge of wire it needs for the length of run and current demands. The negative pole is supplied by the entire chassis of the vehicle, ensuring that the chassis has the best supply feed is critical.
Starting with the battery negative pole to chassis, pull the original wire and replace it with at least 4-gauge wire. It is a good idea to match the amplifier power feed cable gauge, if not use a bigger cable. In my cars, I use 1-ga battery to frame cable. You should clean the frame (or body if a unibody car) where the battery ground attaches. This should be secured with a bolt and not a screw. Any paint, rust, scale or grease should be cleaned away as well, you want a nice clean metal only surface. If the factory location does not allow you to use a bolt, move it. It does not have to be in the same location as the factory cable, but it should be as short as possible. You don’t want a 4-foot ground cable if you can help it, as the shorter the cable, the less resistance you will have.
Along with the battery to chassis, you need to run a ground cable to the engine. Most vehicles come from the factory with a ground strap, which is a braided metal strap that ties the engine to the body or frame. While this is ok, these don’t get replace often and are usually heavily corroded, which inhibits the flow of electricity. I like to tie the engine ground to the same point as the battery ground. This eliminates a connection point and really simplifies the entire process. I also like to add a body ground on full-frame cars and when the battery ground cable is attached to a subframe. The actual initial ground point for the entire vehicle (when running) is the alternator case. This is where the electricity is being generated, the battery is merely a storage device.
Another key point, but not part of the big three, is the ground point used for the amps. On full-frame cars, I mimic the body to frame connection in the rear of the car for the amp ground as well. I bolt the amp ground wire (usually off a distribution block) to the body with a bolt and then run a second wire off the other end of the bolt to the frame, making sure the body and frame are both clear of any paint, rust or grease. This might seem like overkill, but a good ground is the first defender of noise.
The last part of the big three is the alternator to battery upgrade. Using 4-gauge power wire, you simply replace the factory wire that runs from the back of the alternator to the battery. This is usually the large post with a nut and a washer. You do not need to route the wire just like the factory wiring, but it is very important for you to route the wires where they are not in danger of abrasion, burns or any other potential hazard, this goes for all wiring in the car.
One key point- if your system has capacitors, it is important that you disconnect or discharge these before working on the system. Caps stay charged and you can create big sparks and potentially ruin the cap (or other components) if you accidentally arc the terminals during the process.
With the big three in place, your system will charger better, provide more voltage (due to less resistance in the system) and be capable of providing the max output of your alternator to the battery and the rest of the system.