When the car is off, the battery inside will not last long when powering electrical devices like radio, headlights, and fans. In this article, I will discuss how long you can play music with the car turned off and how to get the most out of your car battery.
Generally, you can listen to music in your car for 5 to 8 hours without completely draining the car battery. The playback time heavily depends on the condition of your car battery, the audio levels, and if you have an aftermarket audio system/subwoofer installed in your car.
When listening to music without starting your car, you are using the car’s battery to power the radio, amplifier, and speakers.
If you keep listening to the music, the battery will eventually drain to a point where you might not be able to start your car.
How long can I play music with my car off?
Here are the things that will affect the music listening times when your car is off.
1. Health and condition of your car battery.
If the battery in your car is new and in healthy condition, you can expect to listen to music for longer without completely draining (and ruining) your car battery. Similarly, cars with older batteries will die faster when you are listening to music without starting your car.
1a. What type of batteries do cars use?
All modern cars use both AGM and lead-acid batteries.
Around 80% of cars today use older and less expensive lead-acid batteries. These types of batteries are not designed to be fully discharged due to their low DoD (depth of discharge).
Completely draining a lead-acid battery will significantly affect its life, reliability, and performance.
On the other hand, AGM batteries have an 80% DoD (depth of discharge) rate. It is better than 50% of lead-acid batteries. It means that AGM batteries last longer and provide more electrical energy without the risk of being damaged completely.
So if your car has an AGM battery, you can listen to music on the radio for longer without starting your car or ruining the car’s battery.
An important note about car batteries is that sometimes you might need to keep your car batteries idle for them to charge properly. Once it’s charged, you won’t have any issues listening to music.
1b. How to find what type of battery is in your car?
You can look for the labels on the car battery to find its type.
- If your car battery says SLA or lead-acid on its label, it is a standard lead-acid type battery.
- If your car battery says AGM or gel on it, it is an AGM-type (absorbed glass-matt) battery.
If your car battery is outside of the cabin. For example, under the hood, then it should be a lead-acid type battery.
But, if your car battery is inside the cabin, under the seat, or in the trunk, then it should be an AGM-type battery.
2. Electrical systems and safety in modern cars
In some modern cars, the electrical system is very smart. It does not allow you to listen to music or use battery power for more than one or two hours when the car is off.
In some cars, the accessory mode will turn off automatically after 20 minutes to avoid draining the battery.
In some older cars, the car will shut off the radio and other electrical systems when the battery reaches a critically low state. It is done to avoid damage to the lead-acid battery found in the car.
3. Aftermarket head units.
If you have upgraded your car head unit or it already has a more advanced head unit with a large display and features like an LTE hotspot. Then it is likely going to consume more power than an old-style head unit.
Head units with large screens consume more power because of the backlight of the LCD itself and more processing power required to drive the user interface and play videos.
An LTE hotspot in connected cars also consumes more energy when connecting to cellular networks and transferring data.
The head unit also has an amplifier built into it to drive the speakers in your car. This amplifier will vary in power depending on the type of head unit and the number of speakers installed in your car.
In short, if there are more speakers installed in your car, the head unit will require more power to drive them. Your audio playback times on battery power will vary accordingly.
4. Aftermarket subwoofers and amplifiers.
If your car has a subwoofer, then your music-listening times are going to be shortened quite significantly.
Subwoofers need a lot of power to drive them, with the smaller ones consuming at least 50 to 80 watts. A small or low-powered subwoofer will draw as much power as the complete audio system in your car. Usually, the large (and aftermarket) subwoofers might draw 500 to 1000 watts.
Depending on your subwoofer size and its power requirement, your music listening times without starting your car could be just 30 minutes.
Subwoofers and their amplifiers put a lot of stress on the battery. So I would not recommend listening to music for more than a few minutes when your car is off.
5. Other electrical accessories.
Other accessories will affect music listening times when your car is off.
Things like reading lights, fans, air-conditioning, USB outlets, headlights, dash-cams, and other misc electronics, draw power from the battery when your car is off.
How to increase the music listening time when the car is off?
There are several things that you can do to prolong your music listening time when your car is turned off.
1. Turn off useless accessories.
When listening to music with your car turned off, every watt matters. You can save energy by turning off things you do not need including headlights, fans, USB outlets, and other power-sucking devices.
If your car has a refrigerator (mini-fridge), turning it off will significantly increase the listening time in your car, when on battery power.
2. Turn down the volume.
If you are not partying hard in your car, turning down the volume will make your karaoke sessions last long. More volume means the amplifier will output more power (watts) to your speaker. Therefore, lowering the volume will increase the music playback time when your car is off.
3. Turning down the subwoofer or turning it off.
The subwoofer consumes the most power in a car’s audio system. Turning the subwoofer’s volume down or turning it off completely will greatly increase your music listening times when your car is off.
Sure, the bass would be low, but your battery won’t die in just 30 minutes and you will still be able to start your car normally.
4. Turn off the LCD on your head unit
Most head units have the option to turn off their displays. If you are just listening to audio and not watching any videos, I would suggest turning the display off.
In some head units, the screen automatically goes to sleep when no content is displayed on it. You can check the settings of your head unit to find out more about this feature.
5. Getting a new battery.
A new battery is always going to last longer. No matter if you are playing music or using other accessories in your car when it is turned off. Just like our phones, car batteries perform better when they are new. As car batteries age, they lose their designed capacity and won’t hold a charge for long.
Does listening via Bluetooth consume more energy than aux when the car is off?
You can listen via either Bluetooth or aux, and you would never notice a difference. The difference in power consumption when listening via Bluetooth or aux is so little that it does not affect the overall listening times in a car.
What will happen if the car battery drains while listening to music?
If you have fully drained your car battery while listening to music, you won’t be able to start your car. The battery will not have enough power to spin the starter motor on its own and will need some assistance.
You can use a jump starter or a booster battery to provide the necessary power to start your car. So, your car can begin recharging your battery.
Or you can call roadside assistance for help.
But in my opinion, a jump starter or a booster battery pack will be more quick and easy to get you going.
How to avoid completely draining your car’s battery when listening to music?
Modern cars have smart battery management systems that won’t allow you to use battery power once the battery in your car has reached a certain capacity. These restrictions allow you to start your car safely. This way, you can still drive it and recharge the battery.
Not all cars have smart features that monitor battery health.
So you have to be careful when listening to music on battery power and not drain the battery completely.
You can either monitor the battery voltage on the battery gauge (if your car has one), or look for a battery warning indicator light on the dashboard.
What to do if you have drained the battery in your car?
If you notice the battery is getting low or the battery warning indicator light has turned on. You can start your car and let it run idle, so it starts charging the battery. Also, keep in mind that driving the car will charge the battery faster because the alternator can spin faster and produce more current.
If you can not start your car with a weak battery, you need a jump starter or a booster pack. These compact battery packs can provide the high current your car needs to start its engine.
Jump starters are super portable, easy to use, and act as portable power banks. You can purchase one from Amazon or read my detailed reviews and buying guide in this blog post.
Lead-acid vs AGM batteries