What Can Drain A Car Battery? Here Are 6 Common Reasons To Learn

A dead battery means your car won’t start – making the headlights dim and the engine unresponsive. It can be real trouble should it drop dead in the middle of nowhere or in the morning when you are already late for work. What drains a car battery? Are you curious about what the reasons might be?

What Can Drain A Car Battery?

Many of us wonder what causes car battery to drain. Contrary to popular belief, there are quite a few things that can happen that lead to drained batteries even if you are already equipped with the best-rated car batteries. Read on, and learn about the 6 most common reasons that may suck the juice out of your car battery.

what can drain a car battery when the car is off
What can drain a car battery when the car is off (Photo: mechanicbase.com)

1. Keeping the lights on

Keeping the lights on is one of the reasons what kills a car battery. It’s a mistake that every driver has made at least once in their lifetime as they ask more than one time “what could be draining my car battery”. You have come from work really tired and rushed to the home leaving the headlights on or the trunk open, making the battery drain overnight.

Even the small dome lights can drain the car battery dramatically. Or after packing your car at home, you forget the light so the car battery drains overnight. So, make sure you haven’t left any lights on before closing the door behind you.

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2. Electrical problems

If someone asks you the question “what drains a car battery when the car is off?”. Electrical problems are the answer you should bear in mind. Even if you turn the ignition key off, some functions still keep running. It’s normal for the security alarm, clock, and radio presets to be operational all the time. However, some other components might be switched on if there’s an electrical glitch. For example, the parasitic drain could extend to turning on the trunk and glove box lights, which typically remain off.

3. The battery is in a weak condition

Poor maintenance can leave a battery in a fragile condition, so it may not retain power for a long time and it is what causes a car battery to die quickly. It will be vulnerable to every condition. Even small drains like the clock or the radio’s memory function can leave it dead. Besides, such a battery doesn’t fare well in extremely hot or cold weather. So, take care of it if you don’t want to deal with a dead car in the morning.

Note: Trickle charger is an effective solution for battery maintenance. A trickle charger helps charge a battery slowly and prevents it from overcharging. Therefore, if you need to buy one, here is the list of the best trickle charger products to purchase recommended for you.

4. Corroded or loose battery connections

It’s another consequence of irregular maintenance. Loose or corroded connections won’t let the charging system work properly. It may drain the car battery even when you are driving. Many car models use the alternator to charge radios, clocks, lights, and other small components. In that case, a charging issue can make the draining worse. If the battery doesn’t charge properly, you should have it diagnosed by a professional mechanic.

5. Faulty alternator diode

Faulty alternator
If its diode is corroded, it will cause the circuit to draw power (Photo: pinterest.com)

Another answer to the question of what drains a car battery is a faulty alternator diode. The alternator does the job of supplying power to a few electrical systems and recharging the battery. If its diode is corroded, it will cause the circuit to draw power even when the engine is not running.

6. Old battery

If the car consistently shows the problem of not starting, the problem might be a worn-out battery. An old battery is the last reason that drains a car battery. Typically, car batteries have a lifespan of 4 to 5 years. So, if you often face the drain car battery trouble, it’s probably time for purchasing a quality battery. Changing a new battery is the right choice for you by going to the trustful garage.

What Drains A New Car Battery?

A normal lifespan of a car battery is about 3 – 4 years. After that, the battery can start wearing out eventually and need to be replaced by a new one. If you have got a new battery for your car but you find out that your battery keeps dying? Here are 3 reasons for it:

1. Driving in too many short distances

If you often drive your car short distances, it could be a reason that drains a car battery. There is no surprise that your battery has a tendency to end too soon. The main function of the car battery is to supply power to the vehicle’s ignition. Driving too many short distances means your alternator doesn’t have enough time to recharge between starting and stopping your vehicle. Gradually, it makes your battery drained and doesn’t last long as it should.

2. Extreme hot and cold weather

If the weather gets too high (above 100 degrees) or drops too low (below 10 degrees Fahrenheit), this will result in a bad impact on your car battery. Leaving your car in these bad temperatures for a long period of time will force a build-up of lead sulfate crystals. The sulfate buildup is one of the main reasons that shortens your battery life and increases the recharged time that your battery needs.

3. Faulty charging system

What drains a car battery could be a faulty charging system. In order to recharge your car battery, the alternator of your vehicle must provide it with energy. If some parts of the system go wrong, it is not surprising that your car battery will be dying too soon.

What Happens If Your Battery Drain?

If you have a drained battery, and you ignore it, the battery will drain to 0 % and dead. So most of the time you can not start the engine. Think about you are driving on the highway, and you have a dead battery. You will be in trouble since everything will be delayed and it affects other drivers too. Or you are about to go to work or date but your engine does not start? What a bad day. So remember to check your car or go to the garage to make sure your car works continuously.

How To Detect Battery Draining

It is frustrating to have a battery that won’t hold a charge, and figuring out what’s causing the problem can be tricky. Given that the cause of the battery drain is not human error, you will need the assistance of a qualified mechanic who can diagnose your car’s electrical problems and determine if it’s a dead battery or something else in the electrical system. Or else, you may also learn these tricks to perform at home.

1. New battery

In case your battery is still new (car batteries have a lifespan of approximately six years), a jumpstart should be all you need to get your hand dirty. This solution comes with jumper cables or a standalone jump started stashed away in the truck. Since the battery is healthy, it’ll receive electricity from the other battery, and then charge up properly.

  1. Parking and turning off the car with a jumpstart next to the dead one. You need to pop both cars’ hoods and get the jumper cables out. You should also protect your hands and eyes in case something goes wrong.
  2. Connect from one end of the red (positive) jumper cable to the red post of the dead battery.
  3. Connect from the other end of the red cable to the red post of the charged battery.
  4. Connect from one end of the black (negative) jumper cable to the black post of the charged battery. And the other end to an unpainted metal part in the dead car away from the battery. This safeguard grounds the circuit to prevent sparking.
  5. Start the car with the charged battery. Let the engine run for 5-10 minutes.
  6. Go ahead and try to start the car with the previously dead battery. If it starts, let it idle for at least 20 minutes when you don’t plan on immediately driving. If you do need to take off right away, drive for at least 5-10 miles to completely charge the battery back up.

Before taking off though, remove the battery cables in the reverse order they were attached. That means the black cable is attached to the metal ground first, and so on.

2. Old battery

A new battery is all you need here. However, it’s best to determine if it’s actually your battery and not something else before spending over $80 on a new one.

There are a few popular signs of a bad battery. One evident sign would be the complete absence of any lights or cranking when you try to turn on the car. Another would be the engine cranking furiously but not actually starting. This one is less clear but happens more times than not, it’s the battery.

It’s easy to jump straight to towing the car to a garage if it won’t start, but you’ll spend less time and money by doing a little self-diagnosis.

Note that you’ll most likely be able to jump a dying battery to get somewhere, but there’s a good chance it won’t begin under its own power if you try it again with the same bad battery (i.e. don’t strain yourself somewhere).

Sometimes the battery can be so damaged that it’s unable to take a charge for a jumpstart, too. The best way to know for sure is by taking your battery somewhere that does free battery testing. Auto parts stores like O’Reilly, Autozone, and Advance Auto Parts will all offer this—then you can buy a new one right there if need be.

Watch the video below to see how to check for and fix a car battery drain in your car:

What You Should Do To Avoid Drained Battery?

  1. First, make sure you turn off all the interior lights and that nothing left is turning on before you leave the car. Same with the radio, you should turn it off if you do not drive. Interior lights and radios when turned on can drain the battery.
  2. Second, keep the battery clean. It is really important and you should do it frequently. Use a dry rag to wipe off any dirt or residue near the terminal and connections areas, An unclear battery can sometimes be the cause of its damage.
  3. Third, remember to check the cable connections to the battery. The connection must be tightened and cleaned. A loose or dirty connection between the cable and the battery can lead to the draining of the battery.
  4. Fourth, use a portable car battery charger or a jumpstart and charge the battery if it is below the performance level. The charger can be found at the automotive store where you can find other things rather than only the charger. Remember to use the charger’s jumper cable to test the wattage of the battery.
  5. Last but not least, taking your car to the garage for annual maintenance will keep you far away from what drains a car battery. The specialist will check and if it needs, they will replace the new battery for you.

Sump Up

As you can see both old and new car batteries can drain if you don’t take care of them in the right way. Hopefully, after reading this article you will get a deep knowledge about most of the reasons that make your car battery keep draining and do know how to handle them. If you have any questions about “what drains a car battery” or any car questions, feel free to leave us a comment in the box below.