Video Transcript
If your car’s engine doesn’t turn over when you try to start it using the key or push the starter button, and if your battery is less than five years old, it’s likely that the battery needs to be recharged. Even a good battery can lose its charge if the vehicle hasn’t been driven for a long time, if it’s only used for short trips, or if an accessory like an interior light was left on when the vehicle was turned off.
If you possess a portable battery charger, you can recharge the battery yourself. If you don’t have a charger, the experts at AutoZone can assist you in selecting one. If you prefer not to work under the hood, you can bring your dead battery to an AutoZone store, where they will test and recharge it free of charge. However, if you’re watching this video, you likely want to handle it yourself. So let’s discuss the proper method to charge a dead battery right now.
Welcome to the AutoZone DIY Garage. To charge your battery, you’ll need a portable charger, an extension cord, a wire brush, and a voltmeter could be helpful as well. Charging a battery is a straightforward process, but for safety reasons, it’s crucial to do it correctly. Wearing safety goggles and gloves is recommended whenever you work on a car. Make sure that the area where you’re charging the battery is well-ventilated, as charging can produce flammable fumes.
If your car isn’t positioned close enough to an electrical outlet for in-car charging, refer to the video titled “Replacing Your Battery” and remove the battery from the car. Most modern cars have their batteries under the hood, although there may be exceptions. If you can’t locate the battery after opening the hood, consult your owner’s manual. It might be under a seat, in the trunk, or even inside a wheel well.
Did you know that battery electrolyte is acidic and can damage skin and most fabrics? When handling an automotive battery, wear rubber gloves and avoid letting the battery case touch your clothing. Unless your car is quite old or you’re charging a battery from another vehicle like an ATV or lawnmower, the battery will likely be a 12-volt unit with its negative terminal grounded to the car’s chassis or engine block. Double-check to confirm this. Some older vehicles prior to 1955 had six-volt batteries, and some were grounded on the positive side.
A voltmeter can help you determine if your battery requires charging or if another issue like a faulty starter motor is causing the no-start problem. A fully charged battery should show a voltage of at least 12.65V. Even a nearly dead battery can briefly display this voltage. If the battery reads 12.65V, turn on the headlights for a few minutes and then turn them off. Wait a few more minutes and check the voltage again. If it has dropped more than 0.1V, the battery needs to be charged.
Your battery charger comes with a cord that plugs into an electrical outlet and a set of cables with clamps on the ends that can be attached to the battery terminals. Place the charger as far away from the battery as the cables allow, and avoid placing it in the engine compartment where it could cause a connection to ground out.
Before attempting to hook up the charger, examine your battery. One terminal is positive, usually marked with a plus sign, and the other is negative, identified with a minus sign. The positive terminal is typically larger. Clean both terminals with a wire brush to ensure a good connection, as corrosion can hinder charging.
Disconnecting the battery from the vehicle is not necessary if you’re charging it in place. Chargers restore energy to batteries by delivering current measured in amperes. Most modern chargers are automatic and require you to select either 6V or 12V before charging. Most vehicles today use 12-volt batteries. Vehicles manufactured before 1956 might have 6-volt batteries, and heavy-duty vehicles might have 24-volt batteries, which require a different charging setup.
Certain chargers allow you to adjust the amount of current being applied to the battery. Charging at 10 amps is safe for most modern automotive batteries. If the battery isn’t completely discharged, charging at lower currents like 2 to 3 amps will provide a slower, more thorough charge. Before charging, ensure the battery’s electrolyte level hasn’t dropped below the recommended level. If your battery has caps on its cells, remove them to check. The electrolyte should reach the ring below the opening, about an inch from the top. Add distilled water if necessary, but avoid overfilling.
Connect the charger to the battery’s terminals before plugging it in or turning it on. Attach the positive clamp, often red, to the positive terminal of the battery. Then connect the negative clamp to the vehicle chassis or engine block, away from the battery or its negative terminal. To avoid sparks, make sure the charger is only plugged in after the cables are attached to the battery.
Once the charger is connected and powered on, its meter or digital display will indicate whether the battery is charging. Sometimes, a completely discharged battery won’t accept a charge until it warms up a bit, so be patient. Eventually, the display should show that current is flowing to the battery. As the battery approaches full charge, the charging current from an automatic charger will decrease.
Charging a fully dead 100-ampere hour battery at 10 amps can take up to 10 hours. When charging is complete, turn off the charger and unplug it from the wall outlet before removing the clamps from the battery terminals.
That covers the process of charging your battery yourself. If you have any remaining questions, don’t hesitate to consult the experts at AutoZone. Remember, AutoZone is here to assist with parts and more.
