How Many Amps Does A Car Stereo Draw?

Car stereos are more or less built-in with your vehicle when they are delivered from the factory. But how many amps does a car stereo draw? A decent stereo setup will include subwoofers and a speakers that’ll draw about 5-10 amps.

However, not all stereos are made equal. Based on the output level of the music you listen to, the amount of power your car stereo draws might vary.

In this article, we’ll try to address a common question that many car owners have - how many amps does a car stereo use or draw? Besides, there will be some other interesting insights into the topic too. So, hang tight as we dive right in!

Factory head units are decent enough than aftermarket when it comes to the average car owner. But if you want better sound quality and cleaner volume levels with well-defined tones, you will need to add a little extra something.

Yeah, we’re talking about after-market amplifiers installed outside your in-dash stereo. Note that the crisper sound quality does come at a price. You’ll need some more amps to power up the new speakers and sub-woofer system.

Extra Power for The After-Market Speakers

The maximum output power per channel for average car stereos ranks at about 10 watts RMS. It’s a decent setup to shun out usual traffic noise without causing too much distortion.

If you get a compact 4-channel amp, you can dramatically increase this performance but at the cost of some extra power. Standard after-market speakers include separate woofers and tweeters with a power range of 5-60 watts RMS. That’s about six times the factory setup.

So, it’s pretty evident that you need to factor in some extra power or amps for the upgraded performance.

Remember that Wattage equals Volts times Amps when calculating how many amps does a car radio use. 

So, if the amplifier puts out 1000 watts RMS and uses a 12 volts supply, it requires 83 Amps. Simple as that!

Points To Consider

Once you already know about your car stereo’s RMS rating, you can decide whether it’s worth it based on how many amps it might need.

However, if you want to know how many amps does a car stereo draw when off, it’s about 0.03 - 0.075 when you drive it around most of the time.

1. Powering Only the Speakers

If you want to power only the tweeters or speakers, a 2-channel amplifier will be good enough. It works at around 50 watts RMS and will draw about 4 amps of power at a 12V power supply.

2. Powering Speakers and A Subwoofer

The most practical solution, in this case, is to go for a 3-channel amplifier. These setups can take up to 100 watts RMS. So, the power drawn should be around 8 amps when 12 volts are supplied.

But a 4-channel amplifier setup can power up the car stereo even more for a boosted audio performance and keep room for expansion in the future.

Bottom Line

Besides the usual mathematical calculations, you should also factor in the efficiency of the amplifier. No standard amplifier can work at 100% efficiency. So, there will always be a certain amount of system loss when finding out how many amps does a car stereo draw.

Nonetheless, now you should be reasonably aware that your car stereo amp draw is about 5-10 in standard cases and can go up to 12 if you crank it up.

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