Does ACC Drain Car Battery?

by Phil Borges // in Car

Many people wonder if the use of an automobile’s “accessory” or “ACC” mode will drain their car battery. There are many conflicting answers to this question, but this article will try to help you find the answer.

What can drain the battery when the car is off?

There are several things to consider when looking at how a car battery is drained. The biggest drain on the battery when the car is turned off comes from keeping all of your electrical devices running while you are not in the vehicle. Things like lights or a cell phone charger might be connected to power through a USB port and continue to draw current even though it appears that nothing is being used.

Another cause of battery drain starts with the car itself. Leaving your lights on overnight is a very common way that people accidentally kill their batteries because it only takes about 20 minutes for them to start draining. If you are parking in an area where there is some ambient light, make sure to turn off all interior and exterior lights before leaving the vehicle.

One of the most common culprits is a faulty alternator. When the alternator isn’t working properly, it can’t properly charge the battery, which can lead to a drained battery.

A bad connection in the wiring system is also another cause of battery drain. If there’s a bad connection anywhere in the system, it can cause energy to be lost and result in a drained battery.

Corrosion can also cause a battery to drain when the car is off. Corrosion can develop on the terminals or connectors of the battery, which will prevent it from charging properly and will eventually lead to a dead battery.

One last common cause of battery drain is Parasitic drains. Parasitic drains on a battery are the clock, the radio, and the electric seats. Other items that can draw current when the car is off included electric trunk releases, security systems, and window motors.

If you’re not sure what’s draining your battery while the car is turned off, you can use a multimeter to test for voltage drops across different circuits in the vehicle. By identifying which circuit is causing the biggest drain, you can then start troubleshooting to see what’s wrong. For example, if you suspect that a certain component is faulty and drawing too much current, you can remove it from the car and see if the battery voltage stabilizes.

Or better yet, you can bring your car into the shop and have it diagnosed by an experienced professional. This way, you can be sure that the diagnosis is correct and make an informed decision about your next steps.

What does ACC mean in a car ignition?

ACC stands for “Accessory.” When you turn your ACC on car ignition, that means that all of the accessories in your car- like the radio, power windows, and so on- will be turned on. It allows you to use various electronic devices in your car while it’s running, such as a phone or a laptop.

ACC usually comes with a few different settings, such as “on,” “off,” and “automatic.” The “automatic” setting means that the device will automatically turn off after a certain amount of time (usually 10 or 15 minutes). This is handy if you want to use your device for a short period of time and don’t want to have to worry about turning it off manually.

What does the ACC setting on an ignition switch do?

The ACC setting on an ignition switch is used to control the amount of power that is sent to the electrical system in a car. When the ACC setting is turned on, it allows the car to stay powered on even when the engine isn’t running. This is useful for things like keeping the car’s AC or radio running while the car is parked.

Many people wonder if turning on the ACC setting will drain the car’s battery. The answer to this question depends on how old the battery is and how often the ACC setting is used. Batteries that are more than a few years old may not be able to handle being powered on all the time, and this could cause the battery to drain faster than usual. If you have a newer car, however, and turn on your ACC setting when you’re not driving for extended periods of time (like at work or while sleeping), then there shouldn’t be any negative effects from doing this.

How to maintain a car battery?

There are a few things you can do to help maintain your car battery and prolong its life:

1. Make sure the terminals are clean and free of corrosion. Dirt and grease can build up on the terminals and decrease the battery’s overall performance. To clean the battery, you can use a wire brush or a piece of sandpaper.

2. Another way to maintain a car battery is to keep it fully charged. A discharged battery will sulfate, which will damage the internal plates and reduce its lifespan. You can charge a car battery with a car charger or by using jumper cables from another car.

3. Keep the car well-ventilated when the AC is on, as this uses up a lot of power from the battery.

4. Have the battery checked regularly and replaced when necessary. Regular maintenance is key to keeping your car battery healthy and functioning properly. Failing to maintain your battery could lead to a costly replacement – so it’s worth taking the time to do it right.

5. Consider investing in a battery maintainer, which will keep the battery topped up and healthy when not in use.

6. You should always keep your car well-maintained by changing the oil regularly and checking all of the other fluids levels. This will help ensure that your engine runs smoothly and doesn’t put too much stress on the car battery.

When it comes to car batteries, prevention is key. By following these simple tips, you can help to prolong the life of your battery and avoid any costly replacements.


The answer to the question Does ACC drain car batteries: depends on the type of car and what you’re doing with the car’s accessories. If your vehicle has a weak battery, then there’s a chance that it will drain faster when running the A/C or other accessories due to increased load. If this sounds like your situation, then it is recommended that you purchase a new battery to continue enjoying your car safely.

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.