You have probably experienced walking out to your car to head for work, only to find that it won’t start. Having a dead battery is inconvenient, but most of the time it is an easy fix. You can get a jumpstart and be on your way. The battery will charge as you drive, and you might not have any further issues.
There are several reasons that your battery dies, one of which is the interior lights. If they are left on when your car isn’t running, they draw on the battery of your car. Since the battery only charges when the car is turned on, it will eventually run out of juice.
When you find your car with a dead battery, you will want to know the cause. Take a look at how your battery works and why the interior lights can drain it.

How Does the Car Battery Charge?
The battery of your car is charging every time your car is running. The alternator produces power when the car is on, and it sends AC power to your battery to charge it. The battery charges when the car is idling, when you are driving, and any other time that your car is running.
The alternator is connected to the crankshaft of your car with a belt. When the belt turns, it spins a rotor that is inside the alternator. It is surrounded by magnets, and when it passes them, an AC current is created. It is converted to a DC current and distributed through your car. This is how electricity is provided to the electrical parts of your car, and it charges the battery at the same time.
Will Interior Car Lights Drain the Battery?
If you leave your interior car lights on overnight, they will drain your car battery. If your battery is weak or at the end of its life, the interior lights can drain it in a short period of time if you have them on while the car is turned off. The battery is designed to keep things on while you are driving and for short periods of time when you turn the car off, but they are not made to keep these systems running when the car isn’t on.
Some newer cars are made so that they automatically shut the lights off when you lock your car. Some of them even cut the lights off after a certain period of time. They are designed this way specifically to prevent this problem. However, some cars are not equipped with this feature. If you leave your car parked with the interior lights on, they will drain the battery.
How Long Will the Battery Last If You Leave the Interior Lights On?
This depends on several different factors. First of all, if you have a new battery that is fully charged, it will take your battery a lot longer to drain. On average, it will last between six and eight hours. However, if you have an older battery that isn’t fully charged and runs out quickly, it can kill the battery in a very short period of time.
Leaving your interior lights on overnight will normally drain your battery, and you will need to jump start your car in the morning. There may be times that it doesn’t drain the battery, but generally, it will.
Why Does the Interior Light Stay On?
The most obvious reason that your interior light stays on is that you forgot to turn it off. This can happen when you get home in the dark, and you need to look for something in your car before you exit.
When you open the door to your car, the lights should come on automatically. Some newer cars have a feature where they turn the lights off after the door is open for a certain period of time. However, other cars don’t have this feature. If your car door doesn’t latch or you leave the tailgate open by mistake, it can keep the lights on and drain your battery.
Sometimes, there is a problem in the car, and you may not be able to turn the lights off. This is usually a problem with the electrical system or a computer glitch, and you will need to get it repaired. You can’t leave the interior lights on all the time without draining and putting wear on your battery.
How Long Does a Battery Last?
Most car batteries last around six years. However, it can vary based on how you take care of it. If it discharges and recharges often, it will shorten the life of the battery. Something as simple as using the battery often when your car is off will shorten the battery life.
If you leave your interior lights on overnight, you are discharging your battery. As it takes a toll on your car, you will notice signs that you need to replace your battery. Your car might hesitate when you crank it to start, or it might take a minute to provide enough power to turn over the engine.
Some cars will have a warning indicator on the dash, and you may notice your remote key or interior lights stop working correctly. It is important to take care of your battery so that your car is reliable and works all the time. Make sure that you close the doors completely and turn the interior lights off.
You should also make sure the headlights are turned off, and don’t leave anything inside the car charging. Many modern cars simplify this for you by automatically turning off the interior lights after a certain amount of time.
Final Words
It is important to know your car and pay attention when you leave it parked. Your battery is essential for starting the car, and if it is drained, you will need to jump it to get going. Leaving your interior lights on for a period of time will drain the battery unless your car automatically turns them off. Pay attention when you leave your car so that it will start up the next time you use it.
Related: How Long Before Your Battery Dies With the Radio On