When upgrading or installing a new DC electrical device careful attention has to be paid to the size of the wire used. If not you run the risk of creating a voltage drop. A voltage drop is where you start out with a certain voltage on one end of a wire or connection, but it drops down when it reaches the other end. An example would be you have 12.8volts in your battery, but you only have 11volts at the main battery terminal of your starter during cranking. To read about voltage drop testing click here Voltage Drop

   This means that the starter in the above example will require over 15% more amperage to start. But this figure can be compounded in constant running systems, as the extra amperage causes extra heat, which creates even more resistance, which causes the voltage to drop even further, etc.

   The best analogy of ever heard to explain this is to look at wire as a garden hose. The voltage is the pressure in the hose and amperage is the water in the hose. The smaller the hose the more pressure that is required to deliver the same amount of water. Everything in your electrical system was designed to work at a specific voltage (pressure) using a specific amount amperage (water).

   For those units to operate at peak efficiency, they need to see the voltage and amperage they were designed for. If they do they will perform at their peak ability and last considerable longer.

   When you upgrade to a high output alternator, stock wiring simply will not do. It would be the same as attaching a garden hose to your fire hydrant. The fire hydrant has the potential to flow enough water through a fire hose and squash a fire, but since you hooked up a garden hose you can only water your plants. The wire absolutely has to be upgraded, or you have just wasted all the potential of the new alternator, in other words you just through good money out the window.

   There is a formula to figure out what size wire you need to use for a given application. Click here to reach it Sizing Formula

   We also have created a wire sizing chart set up for 6,12, and 24vt systems. It is based on an operating temperature of 150F/65C, and a voltage drop of .36vt at 12.8vt, or .44 vt at 14.9vt. Click here to get the colored version Wire Chart Colored

   If your operating temperature is going to be higher, you will need heavier wire. If your system is not located in the engine compartment you can use a lighter gauge as well. The 150F temperature used to create the chart is a good all around average.

   There will always be some voltage drop in your system. OEM manufacturers usually limit the drop to .5 of a volt. In the performance market place we feel this to be too high. But it is understandable why the OEM manufacturers use it. Otherwise the cost of production of a new vehicle would greatly increase.

   But since you are already paying premium money for an aftermarket part, you should be wise and pay a little extra to make it work properly so that you can realize the full benefit of the product.

Sizing Formula