What Size Alternator Do You Need for a Car Audio System? GA S REGULAR Menu Lifewire Tech for Humans Newsletter! Search Close GO Smart & Connected Life > Connected Car Tech 164 164 people found this article helpful
What Size Alternator Do You Need for a Car Audio System?
You might need a bigger alternator for your sound system
By Jeremy Laukkonen Jeremy Laukkonen Writer Shoreline Community College Jeremy Laukkonen is automotive and tech writer for numerous major trade publications. When not researching and testing computers, game consoles or smartphones, he stays up-to-date on the myriad complex systems that power battery electric vehicles . lifewire's editorial guidelines Updated on August 20, 2021 Tweet Share Email Tweet Share Email In This Article
Expand Jump to a Section The Alternator's Role Considering the Options Size Matters Idle vs Rated Output When it comes to car audio, more power means more sound and vice versa. If you want your music to be big and loud with a huge bass response, you need a big amplifier with a big subwoofer—and a lot of power to run it. The Alternator' s Role
The burden of producing all that energy falls on the alternator. The alternator is the part of the engine that charges the battery and runs the electrical systems. Most factory alternators aren't designed to handle loud, high-fidelity sound. If you install a big, powerful amp without making the necessary power adjustments, the car compensates by restricting power to some of the car's electronics. This usually presents as flickering dash lights, dimming headlights, and a weak bass response from the subwoofer. Do You Need a Bigger Alternator
The easiest workaround is to keep the volume at a level that the alternator can handle. If you want a powerful sound to go along with your powerful amp, though, you have a couple of options. Option 1 Install a Stiffening Capacitor
This is like a battery in that it stores electrical charges through a series of conductive plates. Amplifiers can't draw more power from a charging system than what the system is designed to make. Subwoofers are especially problematic because low frequencies require more energy to produce. A stiffening cap allows a car's amplifier to run at higher output levels by providing a reserve tank of emergency current. However, a capacitor is a viable solution only if you experience flickering lights or diminished bass responses at high volumes. If you're still drawing too much power at low or mid volumes, the stiffening capacitor isn't going to cut it. Option 2 Install a High-Output Alternator
In most cases, the solution is to install a high-output alternator. This is an expensive option, but it's the only way to ensure that your high-performance audio system gets the current it needs without compromising your car's electronics. Capacity Considerations
To figure out how much capacity or amperage the alternator must deliver, determine how much extra power the audio system demands on top of the current system. The easiest way to ballpark that figure is to use this formula: amps x volts = watts For example, if you installed a 2,000-watt amp, assuming a nominal voltage of 13.5V, you'd add roughly 150 amps of demand to the electrical system. Also, calculate how much amperage is drawn by the rest of the car, then add that to the sound system. The total amperage you arrive at will be a ballpark estimate of the maximum power draw of the car and indicates how big of an alternator you need (measured in amps). It's best to have a professional figure this out; every car and sound system is different. These figures also don't account for the difference in output produced at different engine RPMs (revolutions per minute). Idle vs Rated Output
For high-output alternators and car audio systems, the rated output of an alternator typically refers to the amount of current it produces at high RPMs—the kind of engine activity found at highway speeds. When your engine is idling—that is, running at low RPM—it will be capable of providing only a fraction of that amperage. In some cases, an alternator may be able to produce only half of its rated output. This is why most people notice problems like flickering lights when idling in traffic or at a stoplight. In this situation, the demand is at its highest while the productive capacity of the alternator is at its lowest. In some cases, turning the volume down while the car is running at low RPMs fixes the problem. Or, choose a higher-amperage alternator. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit More from Lifewire A Simple Explanation of Alternator Output Ratings Can a 12 Volt Car Battery Really Electrocute Someone? Headlights Not Working? Try These Fixes How to Fix Common Car Amp Problems Adding a Second Car Battery for High-End Audio Do I Need a Car Amp Fuse? Do You Need a Second Battery for Car Audio? Car Amplifiers: Do You Really Need Them? The 3 Best Car Stereo Systems of 2022 How to Choose an Alternator: Do You Need High Output? How to Wire Multiple Amps in Your Car Does Your Car Stereo Need a Crossover? A Car's Electrical System Shut Down Causes Ways to Cure Car Audio Static and Unwanted Noise An Overview of High Output Alternators Car Battery Charging and Maintenance Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies