Expert Answers: How To Keep Amp From Draining Battery


Welcome to the Ultimate Guide on How to Keep Amp From Draining your Battery!

What a bummer that you managed to upgrade your sound system and now your battery is getting drained.


There’s hope. You didn’t waste all that money and time to setup your sound system.

There can be many reasons why the amps is draining your battery so it’s time to put on our detective cap and pinpoint the culprit.

Show it to me already!



How to Keep an Amplifier from Draining Battery?


Not to worry. If your amplifier is the culprit here, there are a few ways to fix the problem.


#1 Get a Secondary Battery


When you use an amplifier with a higher RMS rating, the battery feels the strain, right? The simplest solution is to get a secondary battery for the car. But along with that, you must also get a battery alternator.

This way, the primary battery doesn’t get fried while powering the car and the secondary battery does the heavy lifting required to run your high-powered amplifier. And this is definitely the way to go if you are using more than a single amplifier.


#2 Get a New Battery


Your other option is to replace the primary battery with a new one. Make sure this one is at least 13.8 volts so that it can power the amplifier well. While you’re at it, don’t forget to check for the two factors mentioned earlier in this post: ampere hours and cold cranking amps.

These two details will ensure that you have an authentic product. They will also make sure that your battery can handle the extra power required to run the amplifier and give you a heads up in case your battery is about to drop below the required 7.2 volts in 30 seconds and a higher ampere-hour rating will keep the music going for a longer period of time.


#3 Replace the Old Alternator


If you don’t want to get a new battery or an extra battery, you can also replace the existing alternator. A standard model will deliver 80-120 A which is pretty good to power a high-functioning amp.

But if that is not the case, you must opt for a new alternator. This decision will ensure that your battery is not overburdened and will also make sure that the battery gets charged while you are on the road.


Reasons Why Your Amplifier Drains Your Battery

You have the perfect amplifier and you’re ready to go. But soon, you realize that the amp is draining the battery. This is a common problem which might not make you feel all that good. But here’s the good news. There is a tried and tested solution to this problem.

When your car has a standard factory battery, it is meant to deal only with the standard electrical requirements like headlights and a regular audio system. When you add a powerful amplifier, the car has more needs. Now, this depends on the power of the amplifier but problems with the battery are to be expected.

In that case, here’s what you need to know.

Find out your amplifier’s exact amperage. This can be done by looking at the overall RMS rating of the amplifier by 13.8 (volts). The RMS rating is in watts and can range from 100 to 4,000. At 70 percent efficiency, which is pretty good, you will need 10-414 amperage. So, your car’s alternator must support the amperage when it is on the higher end. This, in addition to the regular electrical needs of the car.

If the amperage needed is more than what your alternator can produce, you can confirm that the amplifier is the reason behind your dead batteries. Fortunately or unfortunately, amp draining car battery when off is also a real possibility no matter how good the alternator is.

You can also reverse engineer a solution by buying an amplifier that can be supported by your car battery. For this, you need to understand your car battery’s specs. There are two important factors to note here: ampere hours or Ah and cold cranking amps or CCA. Learning about these terms comes in handy for other battery-related problems too. So, here we go.

Ampere hours tell you how long a 12-volt battery can power your car. So, if you have a 65 Ah battery it means that the battery can give 10 amps worth of charge for 6.5 hours when it is fully charged.

CCA tells you the number of amps your battery gives non-stop for 30 seconds before the voltage falls under 7.2 volts when the temperature is zero degrees Fahrenheit. When it falls below that level, your car will not function.

Now, let’s assume that the standard equipment needs 40 percent of the battery and the rest is for the amplifier. A battery with 710 CCA leaves you with the flexibility to get a 650-watt amplifier. If you get a more powerful amplifier, you will notice the battery draining. But don’t worry, your car will give you a heads up in many forms.

That’s the next section. We’ll also tell you why the draining of your car battery is very bad news.


What Does It Mean When a Car Battery Is Drained?


When you play music non-stop on the road and the amplifier is too much for the car to handle, you will notice that the bass starts to get weaker.

If you ignore it, you will notice that the dash lights start to flicker or the headlights start to get dimmer.

During the day when you are not using the lights, you might notice that the wipers on the windshield are moving slower than they usually do. Eventually, the engine will crank slowly or won’t start at all. And yes, the radio will stop working too.

There might be other reasons your car isn’t starting but a drained battery is almost always the culprit.

A damaged alternator could also be the reason but that is also caused by an overpowering sound system.

Your batteries often die when you forget to switch off lights or play music for too long.

Damaged battery terminals and also not enough water in your batteries are all reasons your battery isn’t able to do the job at hand.

All of this means your problems go beyond just not being able to play music. Your car might stop at any point and unless you are within the network range, and even then, you are likely to be stranded for a while.

You might also like: Why does my amp shut off when I turn up the volume?

Do Subwoofers Drain Car Battery?


Most of the subs available in the market can actually be handled by a standard car battery. However, if you have a small battery, the load falls on the alternator.

This is particularly true for those who want the bass in their music to be amplified which is probably why you got a sub in the first place.

In that case, a lot of people get busy looking for the quantity and sub size of their choice. And it works too when the music blows the lid off the car, figuratively speaking.

But when you are buying a sub, don’t just look at the power rating. That will make sure that the output is louder but you need to do some math here.

If you have a 105 A alternator, you need an amplifier that has a 1,200 watt RMS rating.

That takes your fuse rating to 120-150 A and gives you the balance you are looking for. But this also depends on how you run the amp. If you are going to keep the party going, you must upgrade the alternator.


Conclusions on How to keep your amp from draining the car battery

Now you know what kind of battery your car needs to support the specs of your powerful new amplifier. You also know better than to neglect the car’s alternator when upgrading the audio system.

Finally, there are a couple of things you need to check in terms of wiring to make sure that the amp is turned off when the car is so that it doesn’t fall back on the battery and drain it overnight. If you have these sorted out, you are good to go for a long drive with some tunes on the whole time.


Frequently Asked Questions:

Why Does My Amp Stay On When I Turn My Car Off?

A: One possible answer is that the remote wire is on. This can be changed by making sure that the wire is powered only when you turn the car keys on.

Do Amps Kill Your Battery?

A: Not always. If this happens, it means that the wiring in your car is incorrect, which is stopping the alternator from providing the power your car is demanding. In these situations, the load falls on the battery, which can then quickly drop to zero. If you ignore the situation, it will cause long-term problems for your battery.

How Do You Know If My Amp Is Off?

A: You will notice a distortion in your music output. Another way you know that your amp is off is that there will be no sound even after the music system is turned on. And if there is audio but no distortion, you will still notice that the output has some strange noises along with the music.

How can I play my car stereo without draining my battery?

The best way to use the car stereo without draining the battery is turning off the the lights and the AC and also make sure you disconnect the sub. The stereo pulls only a small amount of current so you can use it for many hours before draining the battery.

To stop the amp from cutting out you need to get a a power capacitor because the voltage has dropped below the recommended amount and with a capacitor you can change that.

how to keep subwoofer from draining battery

Last Updated on November 14, 2022 by Danny Reid