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Powermaster High-Amp Alternator Installation - Have the Power

Posted in How To on January 1, 2008
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With the Powermaster high-amp alternator and high-torque starter in place on our Jeep 4.0L engine, we've experienced quicker starts and more consistent performance from the electrical system and accessories. To avoid any voltage loss to the starter, we used heavy-duty battery cables from Jeepers and Creepers.

With winch, FM transceiver, CB radio, 12-volt refrigerator, and auxiliary lights all installed on a 4x4, the amp draw on the alternator becomes significant. The stock alternator is designed to meet the power needs of a vehicle's base electrical system, but when electrical accessories are added the capacity of the stock alternator can be exceeded and will likely result in unpredictable vehicle performance and ultimately a dead battery. If your electrical system is drawing more amps than the rated amperage of the stock alternator, then a high-amp alternator can help regain charging performance.

The Powermaster high-amp alternator is designed for enthusiasts who require multiple electrical accessories. It's a 170/110-amp unit and is available for multiple vehicle applications, including the 4.0L engine in our '97 Jeep Cherokee. The 170/110 designation means it produces 170 amps under power and 110 at idle. Even still, that 110 at idle is substantially more than that created by the stock alternator under power (stock alternators in Cherokees were typically 90/60 to 105/70 units). Powermaster offers its alternators in black thermal coat, polished, and natural finish, and most include a six-groove serpentine pulley, depending on the application.

Each electrical component draws a certain degree of amperage, so you can choose the output of alternator necessary for your vehicle based on the total amp load that the electrical system and all accessories put upon the alternator. For best results, there must be an equal amount or more power generated by the alternator than is drawn from the vehicle's electrical system and accessories. For example, an electric fan will draw about 6 to 25 amps. A winch or auxiliary lights will draw even more. Add all of those up and you've probably exceeded the stock alternator's capacity. A high-amp alternator will also help keep the battery fully charged even when all of the accessories are in use. When fully charged, a typical battery will read 12.6 volts on a voltmeter, but a high-amp alternator can keep this figure at a constant 14.9 volts.

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