7 Things That Can Drain Your Car Battery (2023)

A lot of things can leave you feeling drained, like an unbalanced diet, a long day at work, or even spending too much time with others. And though your car battery probably isn't going to many social gatherings in its off-hours, there are still plenty of other things that may leave it feeling just as drained.

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.

(Video) 7 Things That Can Drain Your Car Battery

1. You left your headlights on.

If your car battery keeps draining, the first things to check are your lights. Many newer vehicles have headlights designed to turn off after a certain amount of time. But if your car doesn’t have this feature, your headlights may stay on until you either turn them off or till your car battery is completely drained.

2. 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. What may drain a car battery when it's off are things such as interior lights, door lights, or even bad relays.

(Video) Here's Why Your Car Battery Keeps Draining

While your engine runs, the alternator recharges the battery — which is why you typically don't have to worry about the battery dying while you're blasting the radio on your drive to work! But when the engine is off, the alternator can't recharge the battery, allowing little electrical mishaps to drain your battery entirely. The battery strain caused by these electrical whoopsies is known as a parasitic draw.

You can help avoid parasitic draws by turning off every light and making sure your trunk, glove box, and doors are fully closed and latched before leaving the car.

(Video) Car Battery Drains Overnight Or After Days Of No Use! PARASITIC DRAIN

3. Your battery connections are loose or corroded.

The positive and negative terminals connected to your battery can sometimes jostle loose over time. These terminals may also become corroded. If your terminals become loose or corroded, you might have trouble starting the vehicle because your battery can't properly transmit its power! You could even stall out while driving or damage the vehicle's electronic components. You can help prevent corrosion-related problems by regularly cleaning your car’s battery terminals! If you are unsure on how to clean your battery terminals, come visit your local Firestone Complete Auto Care and have an expert technician do it for you.

4. It's extremely hot or cold outside.

Freezing winter weather and hot summer days may cause problems for your vehicle's battery. Newer batteries tend to have more resistance to extreme seasonal temperatures. But if your battery is older, intense cold or heat could weaken its performance or even cause it to die completely! If you notice your battery having a hard time braving the elements, come into Firestone Complete Auto Care for a free battery check — our auto technicians will help diagnose and troubleshoot the issue.

(Video) 10 things that cause your car battery to drain

5. The battery isn't charging while you drive.

Your car relies on your battery when you fire up the engine. But when your vehicle is running, your battery relies on the alternator to help it stay charged. If your alternator isn't working correctly, it can’t charge your battery effectively, which can make it hard to start your car even if you were just driving!

If your car won't start after driving, there's a chance it might be your alternator. Bring your car into a Firestone Complete Auto Care for a diagnostics check to find out what the problem could be.

(Video) EASILY Identify Vehicle Battery Draining Problems(Parasitic)

6. You're taking too many short drives.

Cranking the engine takes a tremendous amount of power from your battery, but as mentioned previously, the alternator recharges your battery while the engine runs. If you’re frequently going on short drives, though, the alternator might not have enough time to properly recharge your battery between pit stops — especially if you have an older battery. In the long run, frequent short trips can shorten your car battery’s lifespan.

7. Your battery is old.

Nothing lasts forever, including your car's battery. In some cases, your vehicle's battery could last up to five years, but that depends on where you live and how you drive. Extreme temperatures, frequent short trips, and general everyday use could shorten the life of your battery to two to three years. If your car battery dies quickly, even after a jumpstart, it might be time for a new one.

(Video) Most Common Battery Drain Causes And Fix For All Cars !!!!

Check and Replace Your Battery

Are you tired of bringing out the jumper cables every time you need to start your car? Get your battery tested for free at a Firestone Complete Auto Care near you. We'll tell you how healthy your battery is and how much life is left in it. Additionally, our Complete Battery and Electrical System check can help locate the issue if something is draining your battery. And if it's time for a new battery, we'll install a reliable replacement battery.


What drains your car battery the most? ›

Top 10 things that drain your battery

What kills your car battery the fastest? ›

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 battery quickly? ›

Here are some of the most common ones:
  • There are too many push notifications and alerts draining the battery.
  • There are too many apps running location services.
  • There are too many apps running in the background.
  • The screen is too bright.
  • The screen is staying on too long before going to sleep.
Jan 25, 2022

What can drain a car battery when the car is off? ›

What may drain a car battery when it's off are things such as interior lights, door lights, or even bad relays. While your engine runs, the alternator recharges the battery — which is why you typically don't have to worry about the battery dying while you're blasting the radio on your drive to work!

How do you work out what is draining a car battery? ›

How To Diagnose the Battery Drain
  1. Step 1: Remove Negative Battery Cable. Negative Cable Removed. ...
  2. Step 2: Check the Draw Across the Negative Cable and Battery Post. ...
  3. Step 3: Remove and Replace Fuses. ...
  4. Step 4: Isolate and Fix the Issue. ...
  5. Step 5: Replace Negative Battery Cable.
Oct 8, 2018

What shortens the life of a car battery? ›

Factors that can shorten its life include an extended period of partial or full discharge, vibration from not being properly secured, under- or overcharging, extreme temperatures, water loss, electrolyte contamination and corrosion on terminals.

Does running AC in car drain battery? ›

Question: Does having your air conditioning on while you start a car engine shorten the battery life? Answer: In a word, no – as long as your car was made in the mid-1980s or later.

Why does my car battery keep dying overnight? ›

This happens when something – a glovebox light, an amplifier, any electrical component – is pulling power from the battery when it shouldn't. Since the alternator isn't generating vehicle electricity, the problem component pulls from the battery, slowly draining it overnight until your vehicle won't start.

What can drain a car battery besides the alternator? ›

Here are six of the most common causes of a drained battery and what you can do to help prevent it from happening.
  • Parasitic Draws. A parasitic draw is anything that uses energy from the vehicle in your car or truck. ...
  • Driving habits. ...
  • Loose or Corroded Battery Terminals. ...
  • Extreme Weather. ...
  • Bad alternator. ...
  • Your Battery is Too Old.
Aug 6, 2021

What makes a battery last the longest? ›

Generally, the larger the battery is, the more capacity it has for energy storage. So even though a big and small battery are both rated at 1.5V, the big battery stores more energy and provides a longer battery life.

How do you drain a battery in 5 minutes? ›

12 Easy and Practical Ways to Drain Your Phone Battery Quickly
  1. Turn on the LED flashlight. ...
  2. Turn on The Notification Sound/Vibration Alerts. ...
  3. Turn on Auto-brightness. ...
  4. Make A Switch to Dark Mode. ...
  5. Turn on the Navigation mode. ...
  6. High-intensity games, movies, or series. ...
  7. Social media and messaging apps.

How do I know if my alternator is draining my battery? ›

If the engine starts but dies immediately, your alternator probably isn't keeping your battery charged. If a jump starts and keeps your car running, but the car can't start again off of its own power, a dead battery is probably your answer.

How long should you let your car run after the battery dies? ›

How Long Does It Take To Charge A Car Battery? If you have jump-started your car, it is recommended to let your vehicle run for at least 30 minutes because it would typically require at least half an hour to charge a dead battery entirely or at least sufficiently.

What should I turn off to save my car battery? ›

Turn off functions like the radio or air conditioner when your engine isn't running to put less wear and tear on your battery power. Extended periods of idling also can wear a battery down.

How many miles do car batteries last? ›

Typically, a car battery will last for about 5 to 6 years and about 30,000 to 50,000 miles before needing to be replaced. It is a relatively minor cost to keep your car running strong.

How often should a car battery be replaced? ›

Service experts estimate that you should replace your car battery every four to five years. Real-world battery life varies depending on a couple of factors, but you can find out how to know if your MINI Cooper battery needs to be replaced in this helpful guide.

Can windshield wipers drain your battery? ›

The answer is no, leaving your windshield wipers on when the car is shut down will not drain your vehicle's battery. Since the wiper blades won't be moving, there's no drain on your battery.

Is it OK to run car AC while parked? ›

Will turning the AC on while parking harm my car even if I put it on a high level? No, not as long as your cooling fans are working. Cars are made to run all day long with the AC on. If they have the cooling fan working, sucking air over the radiator into the AC condenser.

Does leaving the AC on in the car waste gas? ›

Yes: The alternator, which is powered by the engine, is what provides energy to the air conditioner. The engine runs on fuel, meaning you are using up gas when you run the AC.

Why does my battery keep dying but my alternator is good? ›

If your battery has been run dead too many times, has too much internal sediment buildup or is simply too old, it may be losing its ability to hold a charge. This means as soon as you turn off the engine, the battery starts discharging on its own even if the alternator works fine.

What is the most common cause of parasitic battery drain? ›

Several things could be causing problematic parasitic battery drain, including short circuits or electrical devices that remain energized, including: Under-hood or glove-compartment lighting. Headlights. Computer module.

Can a key fob drain a car battery? ›

A key fob will constantly try to communicate with the car. And that does cause a slight drain on the battery, but generally that won't completely drain a healthy car battery,” says Mike Monticello, Consumer Reports' road test manager. “The key fob is, in a sense, causing the issue.

Which brand battery is the best? ›

Top 10 Lead acid battery manufacturers in India 2022
  • Lento Industries Pvt. ltd. - Lento is the best battery manufacturer in India (2022). ...
  • Exide Industries Ltd.
  • Luminous Power Technologies Pvt. Ltd.
  • Amara Raja Batteries Ltd.
  • HBL Power Systems Ltd.
  • Su-Kam Power Systems Ltd.
  • Okaya Power Pvt. Ltd.
  • Base Corporation Ltd.

What is the 40 80 rule? ›

The 40-80 rule is a way to maximize the lifespan of your battery by limiting the damage ; specifically it refers to not discharging below 40% and not above 80%. Charging above 80% becomes increasingly cause damage to the battery life cycle. Normally the life cycle of lithium ion battery is 300 to 500 charge cycle.

How can I make my battery stronger? ›

Choose settings that use less battery
  1. Let your screen turn off sooner.
  2. Reduce screen brightness.
  3. Set the brightness to change automatically.
  4. Turn off keyboard sounds or vibrations.
  5. Restrict apps with high battery use.
  6. Turn on adaptive battery.
  7. Delete unused accounts.
  8. Turn on dark theme.

Can you fully drain a car battery? ›

If you let the charge drop too low, your battery can become irreparably damaged. So, how low are we talking? A typical 12-volt auto battery will have around 12.6 volts when fully charged. It only needs to drop down to around 10.5 volts to be considered fully discharged.

How do I disconnect battery so it doesn't drain? ›

Disconnecting A Car Battery
  1. Start By Turning The Ignition Off. ...
  2. Find Your Car Battery's Negative Terminal. ...
  3. Loosen The Nut On The Negative Terminal With A Wrench. ...
  4. Remove The Negative Connector, Then Repeat With The Positive Terminal. ...
  5. Remove The Battery If Necessary.
Mar 25, 2021

How do I stop my battery from draining so much? ›

Choose settings that use less battery
  1. Let your screen turn off sooner.
  2. Reduce screen brightness.
  3. Set the brightness to change automatically.
  4. Turn off keyboard sounds or vibrations.
  5. Restrict apps with high battery use.
  6. Turn on adaptive battery.
  7. Delete unused accounts.
  8. Turn on dark theme.

Can alternator drain battery while car is off? ›

A corroded or defective alternator diode will faultily continue charging the circuit even when the car off. This, in turn, will drain your car battery and cause the car not to start.

What are the signs of a weak alternator? ›

7 Signs of a Failing Alternator
  • Dim or Overly Bright Lights. ...
  • Dead Battery. ...
  • Slow or Malfunctioning Accessories. ...
  • Trouble Starting or Frequent Stalling. ...
  • Growling or Whining Noises. ...
  • Smell of Burning Rubber or Wires. ...
  • Battery Warning Light on Dash.
Aug 24, 2020

Can AutoZone test your alternator? ›

Alternator Testing

Dim or flickering lights, dead battery, battery light on, trouble starting or other issues. How to get your alternator tested: Just to visit a nearby AutoZone. We'll test the alternator while it's still in the vehicle.


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