Why is System Voltage Important?

   System voltage has been one of the most overlooked aspects of the aftermarket in the past few decades. Your system voltage and amperage is the lifeblood of the modern automotive vehicle. And just like with anything requiring blood, if you lower the amount, it drastically decreases the functionality of the vehicle.

   Just about everything in your vehicle is run by or controlled by DC electricity. Most of these devices were designed to operate efficiently at approximately 14-14.4 volts. If for some reason, typically too high of a load for the systems alternator, this voltage decreases, the performance of ever electrical device is affected.

   When these devices are operated at lower than optimum voltages, their life expectancy decreases. In some cases sever damage can be done.

   Now I know you are thinking, but I have always done that, ran a device like a stereo on just battery voltage, and it survived. You are right, as the design of most DC electrical components have a range of operating voltage. Typically 10.5 volts to just over 15 volts. Going past these figures usually results in instant damage. There are some, but very few exceptions, and they are typically on the high side.

Here are some examples that might help you relate to why this is important:

1.)We frequently see car stereo vehicles where the user spent everything they had on the stereo system. When they burn their first alternator out, they usually don’t opt to spend the extra cash on a high output charging system. A lot opt to go buy another one from the wrecker, thinking $25.00 once a month is no big deal. Then after 6 months they are complaining that the manufacturer of their amps built low quality ones, because they keep cutting out and failing. The reality of the situation is they did enough damage to the amps from running them on too low of voltage. They are the ones at fault, and I have seen many of them told that by the manufacturers. They get no warranty, nor do they deserve one, as it was not the fault of the unit or the manufacturer. It is not just the amps that are slowly damaged either. Everything that is operated on DC electricity in your car is, i.e. computers, lights, wiper motors, etc., gets damaged when operated on low voltage

2.) Staying with car stereos for a moment. We recently did a very high end charging system for a customer. He had intended on using 2 feed lines of 2/0 wire. We upgraded those two lines to 4/0. The difference being he was going to lose 1 volt through the 2/0 lines. So instead of the amps seeing 18volts, they would have only gotten 17volts. The difference the 1 volt made, just over 700watts of output from his amps. Not often you can buy a high end 700watt amp for less than the $75 difference in the price of the wire (they were very long cables).

3.) The difference in engine performance is also affected. Most electronic ignitions are designed to run good at just over 14volts. They actually perform better at higher voltages, but not many applications benefit from this increase after 15volts. But going the other direction, running these systems on battery voltage or below (i.e. running with no alternator). Has a dramatic effect on their output potential. Simply put, more voltage in equals more voltage out. Your fuel pump is also dramatically effected by voltage, the higher the voltage, the more the pressure.

   We had a very skeptical customer once, that I spent over 30 minutes explaining this to. He eventually gave in. I seen him at the track 2 months later, and he had just installed the alternator (he had doubted it all the time). Anyway he had just finished his first run with the new alternator. He threw the belt at about the 660ft mark because of bracket twisting. He also had to get out of it coming off the line, for the first time in years his suspension wasn’t set properly. But he still gained 2 tenths and 7mph. The only thing that changed was his system voltage, going from 12.8 and decreasing, to 15.0 steady.

     So I hope you can see the effect voltage has on your entire vehicle. You want a minimum of 14volts in your system. Most will we see noticeable gains from having up to 15volts steady in their system as well. Very high rpm motors, and car stereos will see gains going from 15 to 18/20 volts. But remember that if the system was originally designed for use with a 12volt battery, using over 15 volts can damage it. So you must contact the manufacturer to see about compatibility. Usually you will be required to upgrade your system to run at 16-20 volts.