Does ACC Drain Car Battery? Things You Need To Know

People have different opinions on what happens when you leave your car on ACC. Some say your battery will be drained and others say that everything will remain the same.

If you have always wondered whether leaving your car on ACC will drain the battery, then here is the honest truth and not just rumors or opinions.

ACC can and can’t drain your car battery. Does this statement make you even more confused? Don’t worry, I will explain further. As you may already know, your car’s ignition has 4 faces.

The first face is when the key turns the car off, this is followed by ACC, ON, and then we have the final position which engages the starter and the engine is cranked. We will look more into this process later on.

When you turn the key into the second position which is the ACC, you turn on some of the electric components of your car. Depending on your vehicle, the ACC may turn on the stereo, cigarette lighter, and power seats amongst others.

Other than the above components which don’t consume much power, ACC also turns on energy-thirsty components such as ventilators, defrosters, and headlights.

Depending on what electrical functions you are running when the car is on ACC, it may or may not drain the car battery.

For example, let’s say you just leave the car on ACC and every electrical component on your car is switched off, it can stay in that state for hours. And whenever you engage the starter, your engine will crank without any fuss.

However. If you play loud music, switch on headlights, and other energy-thirsty electrical functions, your battery will be drained and your engine won’t start.

I have also seen some cars with old batteries being drained when the car is on ACC and not running any electrical functions.

You know your car better than anyone else. If your engine is new and everything is performing optimally, your battery can last for at least two hours when on ACC and whilst certain electrical components such as the radio is on.

However, to prevent your battery from dying up on you. Always turn on the car regularly and let it run for a minute or two so that the battery can recharge.

For cars with old batteries, don’t risk leaving your vehicle on ACC. Chances are, your battery will be drained faster than a new one.

does acc drain car battery

How Long is It Safe to Play Radio in ACC?

I am sure a good number of people researching this topic are those who love to listen to radios when they are parked at their favorite chill spots. How long you can play the radio when your car is in ACC also depends on a couple of factors.

If you have a standard entertainment system installed in your car and your battery is in perfect condition, you can listen to the radio for at most two hours without having to switch on the engine for a recharge.

However, if your system is quite advanced and needs a lot of power, it can drain your battery in 30 minutes or less.

When manufacturers were assembling vehicles, they didn’t intend for components such as radios and lights to be used when the car is not in motion. That’s why your battery juice can’t sustain running these functions when your car is on ACC for too long.

If you are worried that your battery can’t run your car’s electrical systems for too long when the engine isn’t on, then you are better off keeping the car powered up.

What about Charging My Phone While the Car is in ACC?

The amount of energy needed to charge a phone is very low. And that’s why charging your phone when the car is in ACC won’t significantly reduce the battery life.

Not unless you do this for a prolonged period, you have got nothing to worry about if you are just charging your phone for a couple of minutes.

If you happen to be running other electrical processes alongside charging your phone then you risk draining your battery.

What Does ACC Mean?

Most car owners know that when they put their car in ACC they can have access to some electrical components in their car.

However, not all know what it actually means. ACC stands for accessory. It is the second position out of the four found in the ignition switch.

When switched on, ACC unlocks some of the convenient electrical components in the car such as the lighter, power windows, and car stereo.

Unlike the ON position that unlocks all electrical functions on the car, ACC only switches on key functions in your vehicle.

Some of these functions that are available when the car is in ACC, can drain your battery. We have already discussed them in the first section.

It is crucial that all car owners understand how powerful their battery is and if these systems can suck the juice out of their battery.

Is It Bad to Leave My Car in Accessory Mode?

If you are a motorist who is keen on fuel consumption, then you must always leave your car on ACC when just relaxing in your vehicle. ACC will keep the radio on and you can charge your phone amongst other activities.

It is not bad to leave your car in accessory mode. As a matter of fact, it is one of the best ways on how you can save up on fuel and take care of the environment.

So, if your battery is in excellent condition, you can always leave it in accessory mode. However, avoid doing so if you have a poor battery.

How Do I Turn on Accessory Mode?

There are two ways on how you can go about this and it depends on your car model. For those whose cars use keys for ignition, ACC is written on the starter. Just slide the key to that position and your vehicle will enter ACC mode.

For car owners with push-to-start vehicles, you just have to press the start/stop button once without pressing on the brake.

If you press the brake, your engine will crank. When you press the start button twice without pushing in the brake, it automatically goes into ON mode.

Will Acc Kill My Battery?

No, it won’t. ACC is just a mode for vehicles and it doesn’t use up your car’s battery not unless you switch on several electrical components and forget to recharge your battery for a long duration.

How Do I Preserve Battery Life When a Car is in ACC Mode?

For the lovers of park and chill, you will definitely use the ACC mode for your car regularly. So, here are ways you can preserve battery life when your car is in ACC mode.

  • Ensure your engine runs for a considerable amount of time before you turn it off. This ensures your battery is fully charged and won’t drain faster.


  • When parked, turn off all lights if possible. Your car’s lights use up a lot of battery juice. If left on for long, your battery will die on you even if it is new.


  • If you must listen to the radio, then disconnect amplifiers and sub-woofers. If you are relaxing in your car and want to have a good time, you won’t disconnect your audio system. So, turn on your car after every 30-45 minutes. Doing this will recharge the battery and ensure it won’t drain completely. If this is an activity that you enjoy, I would recommend you visit a mechanic and they can install another battery for your radio system. This will ensure the battery for your car doesn’t get drained.


  • Thanks to technological advancements, you can invest in Bluetooth speakers which come in very handy when you are outdoors and want to enjoy some good music.


  • Replace your old battery.

What Do I Do When My Car Battery Dies While Listening to the Radio?

This is a normal occurrence and many car owners have been a victim of this. When your battery dies because you left the car in ACC mode for long and you were probably listening to a radio. The only solution is to jump it.

To do this, you will need a set of jumper cables and another car to jumpstart your car.

The reason why I advise most car owners to develop a habit of keeping the engine running or recharging the battery regularly when parked and listening to the radio or using other car electrical functions is because of one reason.

It’s not always when you will remember to carry your jumper cables. Secondly, you may be parked at a destination with no other cars nearby.

These two scenarios will leave you stranded and cause a lot of inconveniences when your battery dies. Therefore, every car owner should always be aware of the state of their vehicle.

If you want to drive to the hills and enjoy some fresh air, make sure that your battery is well charged and it can accommodate hours of playing the radio. Lest you will be left stranded with a dead battery.