Is My Car Battery Dead? 8 Warning Signs That Your Battery Is Dying

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Learn how to jump-start or change a dead or dying car battery
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Nothing is more frustrating than a dead car battery, and often, drivers don’t realize the battery is dying until it’s too late. In this article, we’ve gathered all the most common signs your car battery is dying or dead, and we’ll teach you how to jump-start your car and replace a dead battery with expert tips from automotive repair specialist Duston Maynes. Plus, find out what causes car batteries to die, how to extend your battery’s life, and answers to other common questions about car batteries.

Weak Car Battery Symptoms

  1. The car won’t start, is slow to start, or starts only to die immediately.
  2. The car has electrical issues like failing interior lights or headlights.
  3. The battery warning light on the dashboard is on.
  4. The battery is leaking, corroded, swollen, or cracked.
  5. The battery is emitting a rotten egg smell.
Section 1 of 6:

8 Signs Your Car Battery is Dying or Dead

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  1. This is one of the most common signs a car battery is dead or dying. Turn your key in the ignition and see if the car starts. If the battery is dead, you may hear a clicking sound, or nothing will happen at all. If it’s dying but has a bit of power left, the engine may stutter or emit a moaning when you turn the key, and it may take several tries before the car starts. [1]
  2. If the battery warning light on your dashboard comes on , it’s a good indication that something is wrong with the battery. This doesn’t always indicate a complete battery failure, but the problem will eventually impact the battery’s life if it hasn’t already. This is a good sign to check your battery. [2]
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  3. Sometimes, a dying battery may have enough juice left to start the car. However, the engine may idle for just a few seconds before turning off again. Just like a car that refuses to start , this is a common sign that your battery is dying and needs to be replaced. [3]
  4. Normally, your car’s dome lights will turn on when you open a car door. If they don’t, this could be a sign that they’re not receiving power due to a weak battery. Unless you’ve turned off this function or the fuse is blown, this is likely a sign to check your battery. [4]
    • A dying car battery can also lead to other electrical issues. Your power windows may move more slowly, your radio might cut in and out or not work at all, or your lights and radio may come on, but the car won’t start.
  5. Your car’s headlights will often appear duller and dimmer than normal when the car’s battery is dying, as there isn’t enough power for them to function normally. The lights may adjust their brightness randomly or not turn on at all. [5]
    • If this is the only sign, there could just be something wrong with your headlights. However, when accompanied by one or more other warning signs, it’s likely an indication that your battery is dying.
  6. Pop your hood and take a look at the battery itself. If there is evidence of corrosion or leaking (like dried fluid or blue, powdery battery acid), it’s time to replace the battery. Similarly, if the battery box appears swollen or cracked, it needs to be discarded. [6]
    • A misshapen car battery needs to be properly disposed of via recycling. Ask your local auto repair shop how to do so. [7]
    • Handling a leaky battery can be dangerous. Never touch battery acid with your bare hands. If you have to remove the battery yourself, wear gloves.
  7. Dying batteries sometimes emit a rotten egg smell. This is because car batteries contain sulfuric acid, which may leak from the battery. This acid can be dangerous and corrode your car’s electrical system. If you notice an odd smell, have your battery replaced immediately. [8]
  8. This may seem pretty obvious, but if your car can’t start without a jump, the battery is probably dying. This may happen if the battery was drained because you left your lights on or if it’s getting too old to hold a charge. Jump starts only work if the battery is weak, not if it’s completely dead, so try to get the battery replaced as soon as possible to avoid having to tow your car. [9]
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Section 2 of 6:

How to Jump Start Your Car

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  1. Have someone with a working vehicle park as close to the dead car as possible. In most cases, the battery is located beneath the hood, so parking hood-to-hood is ideal. Sometimes, though, the battery may be located elsewhere (like the trunk), so check your owner’s manual if you have trouble finding it. [10]
    • If you suspect your car battery is dying and don’t see any obvious signs of corrosion, try jump-starting it first to see if you can recharge it before replacing the battery altogether. It could’ve died because of a fluke, like leaving your lights on or being exposed to cold weather. If you have to jump-start it frequently, however, it’s probably time to see a mechanic or replace the battery.
    • If your battery is located somewhere other than beneath the hood, Maynes says it’s called a “relocated battery.” Vehicles with these batteries have “jump points underneath the hood,” so refer to your owner’s manual for instructions on how to jump-start your car.
  2. Once you’ve found your car’s battery, look for the battery terminals, which are metal nubs located on the top or side of the battery. Keep the metal clamps of the jumper cables from touching each other while clipping the batteries, and wear gloves and protective eyewear. Follow these steps to properly attach the jumper cables: [11]
    • 1. Attach a red clamp to the positive (+) terminal on the dead battery.
    • 2. Attach the other red clamp to the positive (+) terminal on the booster battery.
    • 3. Attach a black clamp to the negative (-) terminal on the booster battery.
    • 4. Attach the other black clamp to an unpainted metal part on the car with the dead battery.
    • Maynes says attaching the second black clamp to an unpainted metal part prevents the energy spike from “[jumping] over and [spiking] your system” when the car starts. Otherwise, it could damage your alternator.
  3. First, start the car with a good battery, letting it idle for a few minutes to charge the other car’s battery. Then, try starting the dead car. If it doesn’t start immediately, continue to charge it for a few minutes. When it starts, it should be charged enough to run. [12]
    • Generally, it should take about 5 minutes to jump-start a car, but it could take longer depending on outside factors, like cold weather.
  4. Leave both cars running as you disconnect the jumper cables, as the car with the dead battery may not start again if it’s turned off too soon. Disconnect the jumper cables in the reverse order they were attached. Make sure the metal clamps do not touch each other as you disconnect them. Follow these steps to disconnect the cables properly: [13]
    • 1. Disconnect the black negative (-) clamp from the jumped (dead) car.
    • 2. Disconnect the black negative (-) clamp from the booster car.
    • 3. Disconnect the red positive (+) clamp from the booster car.
    • 4. Disconnect the red positive (+) clamp from the jumped car.
  5. Now that the battery has a bit of juice, the alternator needs time to charge it further. To ensure your battery is charged properly, drive the vehicle for at least 20 minutes before turning it off. [14]
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Section 3 of 6:

How to Replace Your Car Battery

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  1. While changing a car battery yourself isn’t too difficult, it can be dangerous if done incorrectly. If you’re not sure about your abilities, play it safe and have a mechanic or other auto professional replace it for you. This may cost a bit more than doing it yourself, but it isn’t worth injuring yourself or causing damage to your car. A professional can also determine if the car battery is dying or if something else is the problem. [15]
    • If you feel confident that you can replace the battery yourself, proceed to the next steps.
  2. Turn off the ignition and any accessories, and set your multimeter to 20V DC if it isn’t auto-ranging. While wearing gloves, attach the red, positive (+) multimeter lead to the positive battery terminal and the black, negative (-) lead to the negative terminal. Turn the ignition key to the “On” position and turn the headlights on for 30 seconds. If the reading is over 12.5 volts, the battery is fully charged and in good condition. If it’s between 12-12.3 volts, it’s operating at 3/4 capacity and shouldn’t need to be replaced right away. If it’s at 11.8 volts or lower, it’s in critical condition, operating at only 25% capacity, and needs to be replaced. [16]
    • Sometimes, it may seem like your battery is to blame when something else is actually wrong with your car. Testing the battery is a great way to see if it actually needs to be replaced or not.
    • If the battery isn’t entirely dead, try jump-starting it before replacing it. If nothing is obviously wrong with the battery, it could’ve died on a fluke, like cold weather.
    • If you’re not comfortable testing the battery yourself, take your car to a professional. Generally, it’s recommended to have your battery tested at least twice a year.
  3. Not all car batteries are the same, so make sure you choose a replacement that will work with your car. Note the size, dimensions, and part number of the original battery, as well as the year, make, model, and engine size of your car. Take this information to your local auto parts store to find an appropriate replacement. [17]
  4. If it isn’t already, put your vehicle in park and engage the emergency brake. Pop the hood and locate the battery. Use a socket wrench to loosen and remove the black, negative (-) terminal. Then, repeat the process with the red, positive (+) terminal. Always remove the negative terminal first when replacing a car battery. [18]
    • Before changing a car battery, always make sure the engine is cool enough to work in that area.
    • Wear work gloves and safety glasses whenever working with a car battery. This will protect you in case any battery acid leaks.
  5. Use a socket extension to remove the clamp that holds the battery in place, then remove the battery from its tray. Car batteries can be heavy (between 40-60 lbs or 18-27 kg), so keep your hands steady. If the battery is hard to remove, use a terminal battery puller . [19]
    • Do not use tools to try to pry up the battery cable, as this can cause damage.
    • Collect any loose pieces in a bowl or magnetized plate to prevent them from falling into the car.
    • If the battery has a handle, use it to pull the battery out.
  6. Examine the battery terminals for signs of corrosion, like a blue or green residue. To clean the terminals , mix a solution of baking soda and water and use a wire brush to scrub the tray and terminals. Make sure everything is completely dry before installing the new battery. [20]
    • Do not install a battery if anything is even slightly damp.
  7. Place the new battery in the battery tray, aligning the positive and negative ends with the matching terminals. Reinstall the clamps to secure the battery. Attach the red, positive (+) terminal to the battery post and tighten it with a wrench. Then, do the same for the black, negative (-) terminal. [21]
    • Before installing the new battery, install anti-corrosion washers on both battery posts and spray the car’s terminal ends with anti-corrosion solution or gel .
    • After attaching the terminals, try to move the battery to make sure the connections are secure. If the battery shifts, tighten the clamps and cables.
    • If the battery was originally covered, reinstall the cover the way it was removed.
  8. Close your hood and start the car. If it starts properly, the battery has successfully been installed. If it fails to start, double-check that you’ve installed the battery correctly. Otherwise, take it to a certified auto service technician to have it checked professionally. [22]
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Section 4 of 6:

What causes a car battery to die?

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  1. In general, car batteries have a lifespan of 3-5 years, depending on usage and environmental factors. Often, a battery may die simply because it’s gotten old. Look for the manufacture date on the battery. If it’s approaching the end of its lifespan, replace it before it dies completely. [23]
  2. Even if it was minor, a car accident can easily loosen your battery cables or damage the battery case. The damage may not be obvious at first, so it’s important to get your car and battery inspected to avoid unwelcome surprises down the line. [24]
  3. If a car battery is exposed to extremely cold temperatures for an extended period of time, it’s more likely to fail prematurely. At 32 degrees Fahrenheit (0 degrees Celsius), car batteries are 35% weaker than normal, though they’ll try to function at 100%. This will cause the battery to permanently weaken over time until it fails completely. If possible, keep your car out of extreme weather or use a battery blanket if you live somewhere cold. [25]
    • Extremely high temperatures can also damage car batteries. Try to keep your car out of direct sunlight on very hot days. [26]
  4. Corrosion is one of the main reasons a car battery will die . Battery acid will sometimes leak out onto the conductive metal of the connectors, which hinders the battery’s ability to send power to the starter. This acid can also be dangerous if it touches your skin, so it’s important to replace a corroded battery immediately. [27]
  5. Forgetting to turn your headlights off is one of the most common reasons a car battery will die. While newer models have a function that turns your lights off after a certain amount of time, the headlights on older models will stay on until you turn them off or your battery dies completely. This also applies to other electrical accessories like the radio or interior lights. [28]
    • Maynes says leaving your dome or headlights on causes “a parasitic draw,” which causes a module to “stay awake [which will] cause a drop in the battery.”
  6. The alternator is the component that uses energy from your car’s motor to recharge the battery when the car is running. If the alternator isn’t working properly , the battery will drain and have no way of regaining power. Take your car to a mechanic to make sure your alternator is functioning correctly. [29]
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Section 5 of 6:

How to Extend Your Car Battery’s Life

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  1. A car’s battery loses its charge when the vehicle sits idle for extended periods of time. Driving your car regularly is one of the easiest ways to keep your battery in good shape. Try to drive your vehicle at least once a week to keep the battery well-charged. [30]
  2. Regular maintenance is another great way to keep your battery healthy. Dirt and corrosion cause car batteries to deteriorate faster, so clean your battery terminals regularly (at least once every 6 months). Be sure to wear rubber gloves and goggles or other eye protection when handling the battery. [31]
    • To clean car battery terminals, disconnect the cables (starting with the negative cable) and inspect the battery for buildup. Mix a teaspoon (7 g) of baking soda with some water and apply the paste to the terminals. Scrub them clean with a steel wire brush or an old toothbrush. Rinse with clean water, then allow everything to dry completely before reconnecting the battery.
  3. Accidentally leaving your headlights or radio on when your car is off will drain the battery. When you turn your car off, double-check that you’ve turned off all electrical components, as well, to avoid discovering a dead battery the following day. [32]
  4. Most manufacturers recommend having your car battery checked twice a year or every 6,000 miles to make sure it’s functioning properly. Take your car to a mechanic or auto service center near you to make sure it’s still holding a charge and is in good condition. [33]
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Section 6 of 6:

Car Battery FAQs

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  1. The exact price depends on the type of battery you get. When shopping for car batteries online, the price can range from as low as $45 to more than $250 for a conventional battery. Expect to spend around $200 for a replacement. Absorbed glass mat (AGM) batteries cost more because of their newer technology and typically cost at least $300. [34]
  2. AGM (absorbed glass mat) batteries use technology from the aerospace industry to make them more compact and lightweight than conventional batteries. AGM batteries are maintenance-free and discharge more slowly than conventional batteries, meaning they retain their charge longer. They typically outlive conventional batteries by 2-3 years. [35]
  3. Car batteries are composed of lead plates alternating with plates of other materials, which are surrounded by an electrolyte solution of sulfuric acid and water. When the car ignition is engaged, the electrolyte solution reacts with the lead plates and starts the car. In short, the battery sends electrical energy to the car’s ignition and starter motor. [36]
    • The alternator helps the battery recharge and maintain a charge. When the engine runs, the alternator siphons some energy from the engine and turns it into electrical energy, which is then transferred to the battery to recharge it.
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      Tips

      • If you know or suspect your battery is reaching the end of its lifetime, replace it before it dies completely. This will save you from the inconvenience and expense of a dead battery.
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      Warnings

      • If you don’t have experience working with cars, take your vehicle to a mechanic or auto specialist. Attempting to fix the problem yourself could lead to injuries or damage to your vehicle. [37]
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      • Never throw a car battery away in the trash. Take it to a service station to have it disposed of properly. [38]
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      References

      1. ↑ https://www.popularmechanics.com/cars/car-technology/a26549/car-battery-how-to/
      2. ↑ https://www.popularmechanics.com/cars/car-technology/a26549/car-battery-how-to/
      3. ↑ https://www.theengineeringchoice.com/signs-of-a-dead-car-battery/
      4. ↑ https://www.popularmechanics.com/cars/car-technology/a26549/car-battery-how-to/
      5. ↑ https://www.carcare.org/2020/07/summer-heat-takes-a-toll-on-your-cars-battery/
      6. ↑ https://autotraining.edu/automotive-tips/engine-information/car-battery-wear/
      7. ↑ https://www.beavertonoregon.gov/795/Batteries
      8. ↑ https://www.theengineeringchoice.com/signs-of-a-dead-car-battery/
      9. ↑ https://autotraining.edu/automotive-tips/engine-information/car-battery-wear/
      1. ↑ https://www.tdi.texas.gov/pubs/videoresource/fsvehiclebat.pdf
      2. ↑ https://www.tdi.texas.gov/pubs/videoresource/fsjumpbattery.pdf
      3. ↑ https://www.tdi.texas.gov/pubs/videoresource/fsjumpbattery.pdf
      4. ↑ https://www.tdi.texas.gov/pubs/videoresource/fsjumpbattery.pdf
      5. ↑ https://www.tdi.texas.gov/pubs/videoresource/fsvehiclebat.pdf
      6. ↑ https://www.themechanicdoctor.com/when-should-replace-car-battery/
      7. ↑ https://www.themechanicdoctor.com/how-to-test-car-battery-with-digital-multimeter/
      8. ↑ https://www.consumerreports.org/cars/car-batteries/buying-guide/?srsltid=AfmBOopEuA7UaMikZOU980t-CwmxieKu7DsecGl4Ou8753iis49sMDPj
      9. ↑ https://transportation.wv.gov/highways/training/TrainingDocuments/Crawfords_Auto_Repair_Guide.pdf
      10. ↑ https://www.jiffylube.com/resource-center/how-to-disconnect-car-battery
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      12. ↑ https://www.jiffylube.com/resource-center/how-to-disconnect-car-battery
      13. ↑ https://transportation.wv.gov/highways/training/TrainingDocuments/Crawfords_Auto_Repair_Guide.pdf
      14. ↑ https://www.themechanicdoctor.com/when-should-replace-car-battery/
      15. ↑ https://lawyers.law.com/legal/why-wont-my-car-start.html
      16. ↑ https://www.popularmechanics.com/cars/car-technology/a26549/car-battery-how-to/
      17. ↑ https://www.themechanicdoctor.com/make-your-car-battery-last-longer-with-proper-care/
      18. ↑ https://www.tdi.texas.gov/pubs/videoresource/fsvehiclebat.pdf
      19. ↑ https://www.themechanicdoctor.com/make-your-car-battery-last-longer-with-proper-care/
      20. ↑ https://www.themechanicdoctor.com/bad-car-battery-vs-alternator/
      21. ↑ https://www.tdi.texas.gov/pubs/videoresource/fsvehiclebat.pdf
      22. ↑ https://www.themechanicdoctor.com/make-your-car-battery-last-longer-with-proper-care/
      23. ↑ https://www.themechanicdoctor.com/make-your-car-battery-last-longer-with-proper-care/
      24. ↑ https://gogirl.co.uk/news-and-advice/check-car-battery/
      25. ↑ https://www.themechanicdoctor.com/when-should-replace-car-battery/
      26. ↑ https://www.renogy.com/blog/what-is-an-agm-battery/?srsltid=AfmBOorkvHZSDi6d_ycVtxuyjR258Kqn2UCcEV46hzG0TmOCdJkDCqz6
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      28. ↑ https://www.tdi.texas.gov/pubs/videoresource/fsjumpbattery.pdf
      29. ↑ https://www.tdi.texas.gov/pubs/videoresource/fsjumpbattery.pdf

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