There comes a time in every car battery’s life when the old pep just isn’t around anymore. No matter how many times you jump-start your car or recharge the battery, your headlights continue to dim, and the odds that you’ll hear the dreaded empty “click” when you turn the ignition key continue to rise. But changing a car’s battery is a simple process. We’ll explain how to get from removal to disposal to replacement in no time–so your car can get the new juice it needs.

Always exercise caution when dealing with car batteries. The danger isn’t just electricity; batteries contain a sulfuric acid electrolyte solution, which is highly corrosive and produces a flammable gas. So turn the engine off, work in a well-ventilated area (like outside), and use protective eyewear and gloves (especially if your battery is more than five years old).

While a leak is highly unlikely, you may want to keep a box of baking soda on hand to spread over possible spills. Also, a battery is heavy (30 to 60 pounds, or 13.5 to 27 kilos), and you’ll be bending into your engine area to remove and replace it. If you have back trouble, you may want some help with this part of the job.


Step 1 Check the battery

Before you plunk down the money for a new battery, make sure you’ve covered all the other possible options. Start with looks. If the top of the battery has cracks in it, you need a replacement.

Next, check the battery terminals, which are the positive and negative knobs that the wires leading to the alternator are bolted onto. Older batteries can produce a sulfate build-up (a whitish-looking residue) that corrodes the terminals and leads to a bad connection. Sometimes a gentle tap with a hammer on the terminals will break away the residue and solve the problem. Or you can scrub them with a pasty mix of baking soda and water using a wire brush or an old toothbrush.

If everything looks fine but you’ve had to jump-start the car more than once, the problem may be that the car wasn’t driven long enough to properly recharge the battery. About 30 minutes of constant driving should do it.

Note: When you drive, keep all unnecessary electric equipment off (such as the radio, the air conditioner or heater and, if possible, the headlights and windshield wipers).

Your car recharges the battery through the alternator, which supplies and distributes electricity after the car is started (when you start the car, you’re using only the battery). The alternator gets its energy from the movement of the actual engine via the alternator belt. If your battery still isn’t charged from extended driving, the alternator belt might be loose. Different car models require different belt tensions, so have it checked by a professional.

Another culprit could be the weather. Extreme cold or heat can affect battery performance–especially cold, which can freeze the electrolyte solution inside. If your battery has removable vent caps (located on the top), remove them and look inside to see if this is the problem (remember to always replace the caps tightly). If the solution is frozen, you’ll have to wait for the weather to warm up, or tow the car into an enclosed area.

Finally, your battery might simply be old and ready to retire. If this is the case, go to your auto supply store and buy a quality model that’s right for your car and climate (some types are better for hot climates; others are better for cold–consult the merchant).


Step 2 Remove the battery

Once you have the new battery, it’s time to remove the old one. Make sure your car is turned off, then scrub the top of the old battery with the baking soda/water mixture and the brush. This will cut down on the possibility of acid problems.

With your wrench, loosen the bolt that holds the negative (-) cable clamp (connected to the negative terminal) and slide the cable clamp off the terminal. Remove the positive (+) cable the same way.

Note: If your cables are unmarked, you may want to mark them as positive and negative before removal to help you remember which is which. Connecting cables incorrectly can damage or destroy the car’s entire electric system.

Next, unscrew the bracket or clamp that holds the battery in the battery tray. You can sometimes do this with your fingers. If not, use your wrench.

Get a good grip on the battery and remove it from the car. Remember, it’s heavy. Once the battery is out, clean the terminal clamps and the battery tray with the baking soda solution (wait for these areas to dry before replacing the battery). However, if the clamps and tray are severely corroded, you’ll want to have them replaced by a mechanic.


Step 3 Replace the battery

To put in the new battery, place it in the tray with the positive and negative terminals on the correct sides. Screw on the bracket so the battery is held firmly in place. Place the positive cable clamp over the positive terminal, and tighten the bolt. Connect the negative cable and terminal the same way. Once they’re both connected, you can close the hood and start the car.

Since the old battery contains highly toxic material, you must dispose of it properly. Do not treat it like regular garbage. You can dispose of the battery at service garages, auto supply stores (they may offer this service as part of your new battery purchase), and recycling centers. You might be charged a small fee for the service, but it’s well worth it.

Once you’re finished, drive easy. With the proper maintenance, your car will be using its new battery for years to come.