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It is a common misconception that the higher the amp alternator, the better. It can be misleading to just look at this number and assume it is more powerful than one with lower amperage. This article will cover everything you need to know about the amp of alternators in order to make an informed decision between two different models.
Facts about Alternator Output
- The power output of an alternator is measured in amps.
- In general, the higher the amp rating, the more powerful it will be.
- It’s important to note that not all engine types work well with a high-amp alternator system and vice versa – some engines need lower amperage for optimal performance.
Therefore, is a higher amp alternator better? The answer is it depends on the demand for your vehicle.
- A low-amp alternator will typically have an output range between about 50 and 100 amps.
- The high-amp ratings can be as much as 400 amperes or more
The Supply & Demand of the Amp Alternator
The amp rating on an alternator is important because it dictates the power output. The higher the amp rating, the more powerful it will be and vice versa for lower amperage ratings.
For example, if your car runs with lights on and needs to draw 80A, then your 400A alternator will produce only 80A. So, what’s the difference between a 100A alternator and 400A alternator in this case?
Alternators are not rated by amps at all but rather amperes per hour (A/H).
- If you’re running a stock vehicle, chances are an alternator with about 60 to 80A/H is enough for your needs. If you have aftermarket audio equipment installed in the car or haul around multiple power-hungry gadgets and accessories then you may want to go up to 110-120A/H
How the current works is that it starts at the battery and then travels through a wire to an electrical component. The higher-amp alternator will produce more volts than the lower-amp one, so when there are multiple components drawing power from the same source (wire), they all have enough voltage. If you’re running with only lights on, your 100A alternator would be more than enough.
The amperage works based on supply and demand, so the alternator supplies as many amps as the vehicle needs.
How many amps do You Need?
If you want to calculate how many amps your alternator should be, use this formula:
(amp-draw of the component) / (.05A) x 20 = amperage
Here are some components that suck up large amperage:
- Air conditioner: 20A
- Audio Amplifiers: up to 70A
- High Beam Head Light: 15A
- Power Windows: up to 30A
In case you want to upgrade your car with aftermarket equipment, you should be aware of the amp that it draws. Use the formula above to help you with the calculation.
How to increase alternator output amperage?
In case you want to increase the alternator output amperage without buying a new one, here are what you can try:
- To generate a higher amperage, it’s best to use thicker wire in the stator windings. That way, you can get more current by reducing winding impedance and providing enough flux to energize the windings.
- Upgrade your alternator with a positive grounding system. This will allow for even more amperage to be provided by upgrading the voltage regulator in order for it to have a higher output;
- Add another rotor and stator assembly. These are like two sets of rotors stacked on top of each other, which creates an additional 30A
Whether you need a high or a low alternator depends on what it will be powering as the alternator works based on supply and demand. Think twice before heading for a high amp alternator because you might not need it after all.