Does Leaving Car Door Open Drain Battery? Is It A Myth Or Fact?

Once you park the car in your garage after a busy day, it is understandable to forget to close the door. But does leave a car door open-drain the battery? If it does then by how much? How does it affect the battery?

The battery is most likely to get drained if you leave the car door open. If the door sensor senses the door is opened, its go-to behaviour will be to light up the internal lights. Keeping it on for a significantly long time would drain your car battery.

Does Leaving Car Door Open Drain Battery?

Yes, leaving your car door open will drain the battery. Even if the door is slightly open, the door sensors will pick that up.

The sensor will send the signal to the computer which will keep the required electrical equipment inside the car running. Thus, it will drain the battery.

How Long Does It Take for A Car Battery to Die with The Door Open?

If you leave the door open and the internal equipment is active then it would not take more than 12 hours for the battery to completely die out.

You are most likely to face battery issues in the morning if the battery has been draining overnight.

But it is hard to assume exactly how long it would take for the battery to die. Because different cars come with different batteries.

Also, internal equipment’s electrical consumption can vary from model to model.

In layman’s terms, the battery will take more than 12 hours to die if you keep the door open.

How To Leave the Car Door Open Without Draining the Battery?

You can open the car door without draining the battery if your car has a separate control for the internal lighting.

You will also have to make sure to turn off any other components that might get running when you open the car door.

You can use the lighting control to turn the lights off completely, even when the doors are opened. Doing this will minimize battery drain.

Also, take notice if other components like computers, suspension pumps are active. You will have to turn them off to make sure the battery is not drained.

What Can Drain A Car Battery When The Car Is Off?

Things like a parasitic drain, corroded alternator, extreme temperature change, electrical glitch, poor maintenance, etc. can drain the battery without your notice.

Nowadays the clocks, computers, and a few parts also draw battery power even when the car is off. But the amount is most likely to be insignificant.

Battery drain due to low maintenance is the most significant cause of power loss. Due to equipment malfunction battery power may get drawn even when the car is completely turned off.

To avoid this problem, stay vigilant about cars’ any weird behavior and do not miss routine maintenance.

Why Does My Car Battery Die After Sitting For A Few Days?

To offer you the best possible experience, some parts of the car still remain active when the car is off. As they always keep drawing power, the battery dies after sitting idle for a few days.

These parts include a few electrical pieces of equipment like car computer, clock, lights to mention a few.

To keep the system always up to date these components keep running if you don’t stop them specifically.

So, if you are going to leave your car for a few days, don’t forget about these components.

How Long Can A Car Battery Sit Unused?

If you store a battery in a secure place outside the car, at best it will hold the charge from 6 months to 1 year. Though a lot depends on the surrounding condition. If kept inside the car, the battery can last up to 3 months at best.

Even when the terminals are disconnected, reactions take place inside the battery. These internal reactions cause self-discharge.

Scientists and engineers have not been able to solve this problem yet.

So, no matter which battery you pick it will eventually self-discharge. Keeping them in optimal condition might save grant them a bit longer life. 

How To Prevent Car Batteries from Dying?

  • Check for the parasitic drain in your car. It is the culprit that most often causes battery drain.
  • Ensure trickle charge if you are not going to use the car for a while.
  • Drive from 15 minutes at least 2-3 times a week, at minimum.
  • If the car will stay in the garage, you can disengage the security system.
  • Keeping the negative terminal of the battery will also preserve the battery.
  • Using a float charger will keep the battery alive if you are going to leave it in storage for a long time.
  • Do regular battery checkups for leaks and spills. Also, try to keep it clean.

How Do You Fix A Car Door Sensor?

Although it is better to replace the car door sensor if it is not performing well, this trick might save you some bucks. Usually, sensors malfunction due to the presence of dust or moisture.

  • Try spraying WD-40 lubricant on the door latch and the hinge. Using something similar to WD-40 would work too.
  • Give it time to penetrate, wait for a minute.
  • Close and open the door a few times. And, that should do it.

If the problem persists, then you should seek professional help.

Bottom Line

It is way too easy to forget to close the door after a busy day. But doing so might cost you way more than you would like. In the worst case, it can leave the battery dead or you might have issues the next time you try to start the car.

So, does leaving car door open drain battery? Yes, it does. As prevention is better than cure, try to make it a habit not to leave the car open. Hopefully, with a little practice, it will become muscle memory and you will have one less thing to worry about.

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