There are few things more frustrating than sitting behind the wheel of your car, ready to go somewhere, only to find that your car's battery is dead. But why is your car battery dead, and what can you do to fix it? Let's take a closer look at what can cause your vehicle's battery to malfunction, how to jump-start a dead car battery, how to test a car battery, and how to replace a dead car battery.
POSSIBLE CAUSES OF A DEAD CAR BATTERY
USER ERROR
A common cause of a dead car battery is simple user error. Either you've inadvertently left an overhead light on, left something charging in the accessory power source, or used too much accessory power when you've only driven a short distance. That means a lot of your battery's power was used when you started your vehicle, but your alternator, which returns power to your battery, didn't have enough time to juice up your battery fully.
BATTERY AGE
Another potential cause of a dead car battery is age. Most car batteries utilize lead-acid, multi-cell batteries. Each cell is filled with a dilute solution of sulfuric acid as well as lead. As your vehicle's battery ages, it undergoes a natural process called sulfation. Sulfation is when the negative plates in your car's battery are coated in sulfate crystals, which can then build up and reduce your battery's ability to deliver power to your vehicle and prevent your car from starting. If your car's battery is between 2-5 years old, this could be the culprit, and it might be time for a replacement.
BATTERY DEFECT
On occasion, a dead battery could be caused by a defect in your automobile's battery itself. If you are repeatedly experiencing a dead battery and your vehicle or battery is new, it might be worth bringing your car into the shop to have a mechanic run a battery test to determine if it has an internal defect.
CAR CHARGING SYSTEM
At times, a dead car battery might not indicate a problem with the battery, per se, but rather your car's charging system. If the battery warning icon comes on while you're driving, this is likely a sign that there's a malfunction within your charging system. You should have a mechanic check to see if your alternator, serpentine belt, battery cable and terminals, and alternator belt are all functioning correctly.
CORROSION ON BATTERY TERMINALS
Finally, a dead car battery could be indicative of corrosion on your battery terminals. These are the posts that connect your battery to the rest of the charging system. At times, corrosion — which looks like white, ashy deposits — builds up between the terminal posts and the battery cables and can cause a reduction in the flow of power in your vehicle. You can use a wire brush and baking soda to remove corrosion from your battery. However, if it keeps occurring, this might suggest that either your battery, battery cables, or terminals need to be replaced.
8 STEPS OF CHARGING A CAR BATTERY
If you find yourself suddenly stranded with a dead car battery, your best bet is to jump-start it using another car's battery. Luckily, if you can locate some jumper cables and a willing Good Samaritan, charging a car battery is relatively simple. Here are some simple steps and tips for properly charging your vehicle's battery.
1. CHECK JUMPER CABLES
Ensure that your jumper cables are clean, the alligator clips are free of corrosion, and that there aren't any tears or kinks in the wires.
2. TURN OFF ENGINES ON BOTH CARS
Make sure that both vehicles are in Park and that the ignitions are fully disengaged.
3. RED ON DEAD
Attach the red alligator clip to the positive terminal of the dead battery. The positive terminal will be marked with a plus symbol and, often, a red plastic flip cap.
4. CLAMP TO THE LIVE VEHICLE
Attach the red alligator clip to the positive terminal of the live vehicle. Then, attach the black alligator clip of the corresponding side to the live vehicle's negative terminal. The negative terminal is marked with a minus symbol.
5. GROUND THE DEAD VEHICLE
Use the final black alligator clip to complete the circuit by grounding the charge. Instead of attaching the clip to the negative terminal of your battery, you'll want to find an unpainted metal surface — such as the body of the car or the metal rod that props open your hood — which isn't near the battery. This is to help ground the electrical flow and prevent sparking from the battery.
6. DOUBLE CHECK
It's important to remember to do this in the correct order. You, Them, Them, You.
7. START THE ENGINE
Start the car with the good battery first and allow it to run for a few minutes. Then you can try starting your own (dead) vehicle. If your car doesn't start at first, check your connections and allow for more time for power to flow between the batteries. Three to five minutes should transfer enough power to start the dead vehicle.
8. LET YOUR VEHICLE RUN
Once you get your car restarted, it's important to remember that your battery will still be low on power. Give it 15-30 minutes of running, preferably at highway speeds, without using peripheral devices like your radio or phone charger that drain the battery. You're less likely to have to jump your vehicle again if you let it recharge with a long drive. For safety, make sure the destination you choose to complete your drive and turn off your vehicle for the first time is your home or intended final destination.
STILL HAVING ISSUES?
If you repeatedly find your car's battery is dead, and you can't identify any user error like an overhead light left on, you'll likely want to test your car battery.
HOW TO TEST A CAR BATTERY
Car batteries can be tested at home or in an auto service shop with a multimeter. Or, if you fancy yourself a bit of a DIY mechanic, you can buy a multimeter online for about $10 and test your battery at home. How to test your car battery with a multimeter?
Set the multimeter to 15-20 volts, hook up the multimeter to the positive and negative battery terminals, and read the voltage. Your owner's manual will give you a clearer understanding of where your battery voltage should be, but in most cases, you're looking for approximately 12.6 volts. A battery might need replacement if its volts suggest it's gone bad.
As your battery ages, it loses its capacity to hold an electrical charge. An old battery can cause some identifiable issues, especially when you're starting your car. If your battery isn't dying, but you're concerned for your battery life, look for the sound of a lazy engine — meaning it takes longer to turn over when you're starting your vehicle — or flickering overhead lights when you're starting your vehicle. If you hear or notice these signs, that's a clear indication that your battery is weakening and that it may be time for a new one. Consider having the battery tested for a definitive answer.
HOW TO CHOOSE THE RIGHT CAR BATTERY
Your car battery is one of your electrical system's most critical parts, so getting the right battery replacement is essential. But car batteries aren't universal, and picking the right one can be confusing. So, what should you look for when it's time to replace your battery?
First, your battery has to physically fit into your car's battery tray. Batteries can vary in size! Consult your owner's manual for battery size guidance.
Second, you want to be sure that you're choosing a battery that will be powerful enough for your vehicle. Consult your owner's manual and see what it suggests is the right number of cranking amps (the amount of power that's required to turn over your vehicle's engine) and choose a battery that fits within those parameters.
Third, you may need to consider cold-cranking amps or the amount of power it takes to turn over the engine in freezing temperatures. This is especially important if you live in a colder climate. It can make the difference between your car dying or starting on a cold winter day.
Finally, you'll need to decide whether a maintenance-required or a maintenance-free battery is the best option for you. While a maintenance-required car battery, which requires regular electrolyte monitoring and top-offs, is cheaper on the front-end, maintenance-free batteries are a lot more hassle-free and don't need much attention. Ensure you're ready for the commitment if you decide to save money and go for the cheaper option.
HOW TO REPLACE A DEAD CAR BATTERY
While you could always have your battery replaced in an auto shop, replacing a dead car battery is something you can easily do at home. If you decide to go the DIY route, there are a few things that you'll want to keep in mind.
First, always check your owner's manual for any safety precautions that might be listed.
Second, always wear gloves and eye protection as battery acid can be quite harmful to the skin.
Third, always disconnect your battery's negative terminal before the positive.
Fourth, never touch a metal tool to the battery posts or terminals.
Finally, be cautious of sparking both from the battery and around the battery.
With these safety tips in mind, here's how to replace a dead car battery:
1. MAKE CERTAIN YOUR ENGINE ISN'T RUNNING
This might seem obvious, but it's an important first step. Put your vehicle in park and turn the engine off.
2. DETACH THE NEGATIVE
Using a wrench or special battery pliers, detach the battery's negative cable by loosening the nut. If there's a lot of corrosion that makes this difficult, you can clean it away either with a solution of baking soda and water or with a little automobile-safe lubricant.
Once the negative cable hardware is loosened, remove the cable by twisting and gently pulling. You can also use a battery terminal puller tool — found affordably at an auto parts store — to help pull it up and off. Use caution because you don't want to break your battery terminal.
3. DETACH THE POSITIVE
Repeat the process of detaching the negative cable on the positive cable to disconnect it, too. Your positive terminal might be under a red plastic hood that will flip back to allow the nut to be loosened and the cable to be removed. If your car doesn't have color-coded cables, it's worth flagging the positive cable with a piece of tape or a twist tie.
4. REMOVE THE BATTERY CLAMP
The battery clamp holds the battery in place. Unscrew it with a wrench or socket to move it out of the way. Frequently, the battery clamp will be three pieces that are attached but independently mobile. So, if the clamp seems stuck at first, try to move the clamp's sidearms up and down to remove them from the battery tray at the bottom. Once they're free, the entire clamp will quickly come off.
5. REMOVE THE DEAD BATTERY
Have a level, dry place to set down the old battery before lifting it from the car. Remove the dead battery and prep the space it leaves for the new battery. How do you prep the space?
6. CLEAN UP ANY CORROSION OR RESIDUE
Clean the tray, battery posts, or battery connector with either a baking soda water solution or automobile-safe lubricant, and a clean cloth or wire brush. If there's too much corrosion and deposits on the hardware and tray, you may need to utilize a battery cleaning solution.
7. INSTALL THE NEW BATTERY
Set the new battery in the empty space and make sure it sits securely in the tray. Attach the clamp — again, by moving the side arms independently into place — and tighten it so the battery doesn't move or jostle in its new home.
8. ATTACH THE POSITIVE
Fit the newly cleaned positive cable onto the positive battery post and tighten the hardware so there's no movement.
9. ATTACH THE NEGATIVE
Repeat the process of attaching the positive cable on the negative cable to reattach it, too. Make sure the connections are clean and the final mount doesn't move at all.
10. DOUBLE CHECK ALL CONNECTIONS
You want to be sure that the terminals are tight against the posts for a good connection. If you can wiggle the cables at all, tighten them more. Loose battery cables can lead to problems starting the car, low voltage, or headlights flickering.
11. PRACTICE SAFE BATTERY DISPOSAL
Finally, because car batteries are highly acidic, they can't simply be thrown away. Instead, you'll need to recycle your battery correctly. Most auto shops (including Bridgestone retail stores like Firestone Complete Auto Care, Tires Plus, and Wheel Works), parts stores, and many car dealerships offer free battery recycling. Just give them a call first to check.