Can a Head Unit Drain the Battery?

Car battery

Yes, and a poorly installed after-market unit head is one of the main reasons why your battery could be draining. Another reason could be that your battery is old or has a low capacity.  

It can be incredibly frustrating if you’ve had your unit head professionally installed. 

If you’re confused about your unit head draining your battery, you’ll be feeling more at ease by the end of this article. 

Head units and stereos, like all electronics, use electricity and will drain the car’s battery over time. Most modern cars will have features that will cut the head unit’s power if draining too much energy while the engine is off. 

This will ensure you still have enough power to start the engine again and not have a dreaded flat battery. 

Two 12 volt feeds with earth are required when it comes to powering an after-market unit head. This means it operates with a dual-sourced system, with one of the 12v feeds being connected directly to the battery. 

If your battery is being drained due to the head unit, it’s because more than 12v are being intercepted by the head unit when you don’t have the ignition turned on. 

When the battery is functioning normally, there’s only ever one 12v feed being received by the battery when the keys aren’t in. 

Diagram showing how headunits and batteries normally contact

Reasons a Stereo Head Unit Could Drain Your Battery

More than one of these cables with 12v being received when the keys are out is the most common reason why your head unit is draining the battery.

Since the head unit doesn’t generate a 12v feed, mishaps during the installation process are the leading cause for a head unit draining your battery. 

When people advise you that your head unit is draining your battery, it’s merely their best guess at what the issue could be. A specialist in audio or an auto-electrician who inspects the problem properly would find that incorrect wiring is draining the battery. As a result, it can be an easy fix! 

There should only ever be one wire that consistently reads as 12v. If any of the other cables are being provided with 12v, you can be confident that’s why your battery is draining. 

You can quickly test the readings of all the wires by using a multi-meter. Once you identify the wire that’s receiving the incorrect feed, the problem is much easier to resolve.

Battery Issues

Another problem could be that your battery can’t store enough power if it’s too old. Or, if your only traveling on short journeys the battery will not have enough time to recharge fully and will continuously be low in power, which could make you think the head unit is continually draining your battery. 

A solution to this would be to charge your battery overnight to get it back up to its full capacity. 

👇 Watch the video below to see how to charge your battery and the best way to go about it. 

How To Fix the Problem

All you need is a multi-meter, and you can test all of the involved wires yourself. This makes it easy to identify which wire is receiving the wrong feed. 

Once you’re confident that you’ve found the wires causing the issue, you can simply move it to a feed that’s ignition-based. 

Types of Wires

There are typical wire colors and their usual meanings. You should check your vehicles wiring diagram first:

  • Black – Earth 
  • Orange – 12v activated with ignition
  • Blue – 12v activated with ignition
  • Red – 12v activated with ignition
  • Yellow – 12v that remains constant 

 

See our full guide on how to connect a car stereo directly to a battery

Final Thoughts

Now that you have a better idea about how your head unit could be draining your battery, you can confidently solve the issue. 

Remember, if you’re being told that your unit head is draining the battery, it’s only because of incorrect wiring during installation. 

Yes, and a poorly installed after-market unit head is one of the main reasons why your battery could be draining. Another reason could be that your battery is old or has a low capacity.  

It can be incredibly frustrating if you’ve had your unit head professionally installed. 

If you’re confused about your unit head draining your battery, you’ll be feeling more at ease by the end of this article. 

Head units and stereos, like all electronics, use electricity and will drain the car’s battery over time. Most modern cars will have features that will cut the head unit’s power if draining too much energy while the engine is off. 

This will ensure you still have enough power to start the engine again and not have a dreaded flat battery. 

Two 12 volt feeds with earth are required when it comes to powering an after-market unit head. This means it operates with a dual-sourced system, with one of the 12v feeds being connected directly to the battery. 

If your battery is being drained due to the head unit, it’s because more than 12v are being intercepted by the head unit when you don’t have the ignition turned on. 

When the battery is functioning normally, there’s only ever one 12v feed being received by the battery when the keys aren’t in. 

Diagram showing how headunits and batteries normally contact

Reasons a Stereo Head Unit Could Drain Your Battery

More than one of these cables with 12v being received when the keys are out is the most common reason why your head unit is draining the battery.

Since the head unit doesn’t generate a 12v feed, mishaps during the installation process are the leading cause for a head unit draining your battery. 

When people advise you that your head unit is draining your battery, it’s merely their best guess at what the issue could be. A specialist in audio or an auto-electrician who inspects the problem properly would find that incorrect wiring is draining the battery. As a result, it can be an easy fix! 

There should only ever be one wire that consistently reads as 12v. If any of the other cables are being provided with 12v, you can be confident that’s why your battery is draining. 

You can quickly test the readings of all the wires by using a multi-meter. Once you identify the wire that’s receiving the incorrect feed, the problem is much easier to resolve.

Battery Issues

Another problem could be that your battery can’t store enough power if it’s too old. Or, if your only traveling on short journeys the battery will not have enough time to recharge fully and will continuously be low in power, which could make you think the head unit is continually draining your battery. 

A solution to this would be to charge your battery overnight to get it back up to its full capacity. 

👇 Watch the video below to see how to charge your battery and the best way to go about it. 

How To Fix the Problem

All you need is a multi-meter, and you can test all of the involved wires yourself. This makes it easy to identify which wire is receiving the wrong feed. 

Once you’re confident that you’ve found the wires causing the issue, you can simply move it to a feed that’s ignition-based. 

Types of Wires

There are typical wire colors and their usual meanings. You should check your vehicles wiring diagram first:

  • Black – Earth 
  • Orange – 12v activated with ignition
  • Blue – 12v activated with ignition
  • Red – 12v activated with ignition
  • Yellow – 12v that remains constant 

 

See our full guide on how to connect a car stereo directly to a battery

Final Thoughts

Now that you have a better idea about how your head unit could be draining your battery, you can confidently solve the issue. 

Remember, if you’re being told that your unit head is draining the battery, it’s only because of incorrect wiring during installation. 

Alex
Alex

I loved my car but was frustrated with my media system. So I upgraded my stereo, making silly wires and precarious phone mounts a thing of the past. The Apple Car Play stereo was so good I wanted to show more people how this could be done and truly upgrade their cars multimedia system!

Founder
StereoUpgrade.com

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