Mike Stiers at Maxxsonics continues his ultra-informative Car Stereo 101 series. This time he focuses on alternators, how to identify a system that requires an upgrade and the effects of using an underpowered alternator.
The alternator powers the vehicle, all components and recharges the battery. A standard factory alternator ranges from 40 amps to 120 amps depending on vehicle. When the alternator is under high demand or the demand exceeds the alternators capability, your voltage will begin to fall and rely on the reserve of the battery. Lets use a 65 amp alternator for example in determining what aftermarket audio equipment the alternator can sufficiently power. In perfect condition, your 65 amp factory alternator is charging at 14.4 volts and is capable of supplying 936 watts. (65A x 14.4V = 936 watts) Your vehicle requires 30%-50% of this to run and operate standard vehicle components. If we use the middle, 40%, you are left with approximately 561 watts for your aftermarket audio equipment. (936W x (100% - 40%) = 561W) This 561watts is based on a 100% efficient amplifier which we know is not realistic. Lets assume you choose an 80% efficient amplifier, which is very efficient. If this amplifier uses 561watts and is 80% efficient, it will produce 448.8 watts for your speakers or subwoofers. (561W x (.8) = 448.8 watts) Going beyond this point and you begin to tap into the reserve of the battery. The result is a decrease in amplifier efficiency and an increase in heat due to decreases in voltage and increases in amperage. This is very hard on the alternator and amplifiers in the system. By now Im sure you see why an upgraded alternator is vital when upgrading your audio system.
DETERMINING POTENTIAL OF CURRENT ALTERNATOR:
Alternator Amperage Rating x 14.4V = Potential Wattage
A x 14.4V = W
Potential Wattage x (Maximum Potential Percentage Used to Run Vehicle) = Watts Available for Aftermarket Audio System
Answer from Step 1 x (100% - 40%) = Watts for Aftermarket Amplifier(s)
Answer from Step 2 (100% Efficient Amp) x (Actual Efficiency of Amplifier) = Watts that can be produced in current application
Mike Stiers over at Maxxsonics has put together another great video for the Car Audio community. Everyone who is thinking of upgrading their stock car audio system to an aftermarket audio system should definitely take a look.
In this video Mike will show you how to prep your car's wiring to handle the upgrade and how to replace your standard car battery with one more suited to the application. In this case, Mike uses the Kinetik KHC1800
A few words from Mike:
So you've decided to upgrade your car stereo system? A great deal of research and planning should go into this purchase since there is a lot to consider. Do you desire a nice upgrade of your factory speakers, are you looking for a Sound Quality overall of speakers, subwoofers and amplifiers, or are you designing a vision-blurring SPL machine? It is important to make a list of exactly what you are looking to replace or add to your audio system so that you can prepare your electrical system for the investment to come.
Many people do not realize that their vehicles factory electrical system was not designed for aftermarket audio equipment. In fact, most factory electrical systems can only handle an audio system of 600 to 1200 watts. The lower end of the scale being the smaller vehicles and most foreign rides, and the upper end being large trucks and sport utility vehicles. As you increase demand, you need to look at upgrading your battery, alternator and most importantly your Big 3.
THE BIG 3
The Big 3 consists of upgrading three wires under the hood of your vehicle. You can completely replace the three wires detailed below, or simply add additional wires to existing factory wires, the choice is yours. The existing factory wires are generally 8 gauge or smaller and are not designed for the high current demands of an aftermarket audio system. It is recommended that you use a nice insulated 0 gauge wire so that you only have to do this series of upgraded once.
The first of the Big 3 is the positive charging wire from your alternator to your battery positive. This wire must be fused within 12 of the positive battery terminal connection. The fuse value should be equivalent to the maximum amperage your wire can handle, which is based on the size and distance of the wire. If you have an upgraded, high output, alternator you will remove your factory alternator charge wire altogether and use the replacement described above.
The second upgrade for the Big 3 is the engine ground to chassis or in some cases, engine ground to battery negative. This is extremely important because this ground is also what ties the alternator ground, through the engine block, to the vehicle chassis. For this step, you want to add your 0 gauge ground to the existing ground. Just clean the area thoroughly and secure the two grounds using the same bolts and locations if possible.
The final upgrade for the Big 3 is the ground wire from battery negative to chassis. If you do not have access to the frame of the vehicle, dont settle for a piece of sheet metal under the hood, but rather locate the strut tower, remove a nut from the thread, sand all paint and debris, connect the 0 gauge ground using a ring terminal on the thread and tighten the nut down. This strut thread has direct access to the vehicle frame and will provide far less resistance than using sheet metal and relying on spot welds. Leave the factory ground in place and clean any dirt, rust or debris from this connection using sandpaper or a stiff wire brush. Through these three steps, you have successfully made huge progress in improving the electrical systems performance, decreased resistance, and enhanced the ability to supply power to your aftermarket audio system.