Modern car batteries are designed to start your car or truck, run all of the electronics, and maintain the vehicle’s computer memory. But over time, batteries do eventually run out of juice — sometimes way before their time.
Here are the real reasons your car battery dies, or keeps dying, and what you can do to get the most out of it.
“Electrical devices or lights left running, a defective charging system or alternator, and extreme weather are some common reasons but maybe it’s just time to get a new battery.”
What Drains A Car Battery?
A dead car battery can be annoying, but it can also be avoided. To help prevent a dead battery, you first have to know what causes one. So, put those jumper cables aside, and check out these seven things that could explain why your car battery keeps dying.
#1. You left your headlights on.
If your car battery continues to run out, the first thing to do is to check your lights. Many newer vehicles have headlights that can be turned off after a certain period of time.
If your car doesn’t have this feature, your headlights may stay on until you either turn them off or until your car battery is completely discharged.
#2. Something is causing a “parasitic draw.”
The simple act of draining a car battery even after the motor has been shut off is known as a parasitic drain or parasitic draw.
A parasitic draw is anything that uses energy from the battery in your car or truck. Some parasitic drains are perfectly normal to power things like interior lighting, clocks, radio settings and alarm systems.
The problem occurs when your electrical system isn’t functioning properly. Issues such as faulty wiring, bad fuses, malfunctioning interior lights and other electronics that fail to shut off will continue to drain your battery while the engine is off.
#3. Your battery connections are loose or corroded.
Cables are connected to the positive and negative terminals of your car battery. For safety reasons, it is customary to disconnect these before performing any maintenance on your car. The battery may discharge if these cables get loose.
The wires can be tightened and appropriately reinstalled to fix this issue, but you should always exercise caution when working on a car’s electrical system to prevent shocks or other harm to the automobile.
Get professional assistance if you have any doubts at all. Another potential cause of your battery’s poor performance might be corrosion at the battery terminals.
With the above safety precautions in mind and the batteries unplugged, cleaning the terminals with a diluted baking soda solution and a brush, coating them with petroleum jelly, and reattaching the cables can be done, but only if you are certain that you can do it effectively.
#4. It’s extremely hot or cold outside.
It seems like batteries die most often in the winter. You go to start your car, and the battery just cannot turn the engine over. But it’s not the cold that kills most batteries.
Hot summer months can deteriorate your battery. Then, you notice that lack of power in the winter. To help avoid damage to your battery from heat, park your vehicle in a garage or under a shelter on hot summer days.
#5. The battery isn’t charging while you drive.
Your car relies on your battery to start the engine. However, when your vehicle is driving, your battery relies on the alternator to keep it charged.
If your alternator isn’t working properly, it can’t effectively power your battery, which can make your car difficult to start even if you’ve just been driving!
If your car won’t start after driving, there may be a possibility that it is your alternator.
#6. You’re taking too many short drives.
Starting the engine uses a tremendous amount of power from your battery, but as mentioned earlier, the alternator charges your battery while the engine is running.
However, if you make frequent short trips, the alternator may not have enough time to properly charge the battery between pit stops, especially if you have an older battery. In the long run, frequent short trips can shorten the life of your car battery.
#7. Your battery is old.
As a car battery ages, it struggles to maintain a charge and loses its ability to function at its best, just like anything else. A new battery holds its charge longer before an old one does.
If your vehicle continuously performs below average and cannot run even with optimum power, then your car’s battery is draining, probably due to an internal factor. Still, it may result from the battery’s numbered days running out and necessitating replacement.
Though various outside circumstances influence the lifespan of a battery, you should typically replace the batteries every four to five years.
Signs of a dying car battery
If your vehicle has a battery marked with LOWER and UPPER on its side, you can check the electrolyte level, which should ideally between the LOWER and UPPER mark. Other most common signs of a dying car battery include:
Before Startup
- The gauges and lights don’t turn on when you turn the key for ignition
- Jumping your battery every 3-5 days or even more frequently
- Battery death within 15-30 minutes of idling with the engine off while other accessories are running
During Startup
- Three or more turns for ignition
- Dimming lights and/or accessories prior to startup
- Greater difficulty in startup after idling for long hours, especially in the cold
During Driving
- Slightly rough stops for traffic
- Intermittent shutdowns of the radio and/or other accessories
- Dimming lights and/or accessories when the accelerator is pressed
How to Prevent Your Battery From Draining, and What Causes It
The life of your car battery depends on where you live, how much you drive, and more. Here are a few tips to help keep your battery from draining.
- Unplug Extra Accessories: Known as parasitic draw, your car battery can drain from stereo components and phone chargers that continue to work when the car is turned off. Also, be on the lookout for glove-box lights, trunk lights, and interior lights that remain illuminated.
- Take a 15-minute drive: At least once per week, take your car for a short drive. As long as your alternator is working correctly, this will help maintain the battery state of charge.
- Don’t leave your headlights on: Turn the switch to the “off” position, even if your lights go off automatically.
- Avoid deep discharging: Don’t leave the lights on or the stereo going while the car is turned off. This can result in a dead battery.
- Tighten and Clean Battery Connections: If your battery terminals are loose or corroded, they can drain or damage the battery. It could also cause your car to stall. If you do find corrosion, it’s easy to clean with a stiff-bristle brush (an old toothbrush works great), and a mixture of one part baking soda to three parts water. With a little elbow grease, the corrosion will vanish. Just be careful not to get any of the baking soda/water mixture in your battery or on other parts of your engine or vehicle.
FAQs.
What drains a car battery when the car is off?
Something Is Causing a “Parasitic Draw.” Even while your car is off, your battery provides power to things like the clock, the radio, and the alarm system. These things shouldn’t have a major impact on your battery. However, interior lights, door lights, or even bad relays can drain a car battery when it’s
What is the main cause of car battery drain?
Electrical devices or lights left running, a defective charging system or alternator, and extreme weather are some common reasons but maybe it’s just time to get a new battery.
How do I find out what is draining my car battery?
If the drain is excessive, the most common way of isolating the cause is removing one fuse at a time. If the current drops to normal when you remove a fuse, then that fuse identifies the offending circuit.
What shortens car battery life?
The abrupt motions of daily driving like quick starts, driving around corners, and panic stops could loosen your car battery. If your battery loosens too much within your engine, this could lead to excessive vibration, which will put a strain on your battery, the surrounding components, and its circuits.
Why is my car battery dying overnight?
Common causes include: Forgetting to turn off interior or trunk lights can drain the battery overnight. Defective relays or switches can fail to disconnect electrical components, causing a drain. Aftermarket accessories like remote engine starters, alarms, GPS devices, or stereo systems can draw power continuously.