How Many Watts Does a Car Alternator Produce?

February 25, 2024

When you need more power than your factory alternator can supply, you'll need a high output alternator. JS alternators, Brand-X, Ohio Generator and Delco Remy are some popular brands of alternators that can handle the extra load from your audio system or other power hungry aftermarket equipment.

The car battery is the car's powerhouse, storing chemical energy that immediately converts to electrical upon igniting the engine. Your battery then distributes the electricity needed to start and run your car's electrical systems. If the battery gets too low, your alternator will draw backup energy from the battery to keep your vehicle running until it is recharged. If this happens often or for too long, the battery may die, causing you to lose power in other areas of your car.

Your factory alternator produces electricity by spinning a rotor past three stationary stator windings -- or wire coils -- surrounding an iron core. As the rotor spins, it generates electricity by magnetically attracting and then repelling a magnetic field created by the stator coils. Each rotor coil has one positive and one negative pole, with the polarity of the negative pole indicating which side of the rotor is receiving power.

The alternator's maximum output is typically set to correspond with the maximum rotational speed of its input shaft. This means that you'll only get 100% of its rated output at full speed, and you'll get less than this at idle or low engine speeds.


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