How to change a car battery: 12 steps (with pictures)

How to change a car battery: 12 steps (with pictures)
How to change a car battery: 12 steps (with pictures)

So far, no car manufacturer has found better than a battery to start and operate certain on-board devices. Today's batteries have a lifespan of three to five years, and what makes them unpredictable is that they suddenly fail: one morning, you can't start! It's time to replace it. Even if you are not a mechanic at heart, it is very easy with a few simple tools to replace a battery.


Part 1 of 2: remove a used battery

Change a Car Battery Step 1

Step 1. Park your car in a flat area

Apply the handbrake, stop the engine and remove the ignition key. For safety reasons, avoid changing your battery on the side of the road, in a place where there are flames, sparks, in short, a safe place. The ignition key must be removed to prevent accidental starting of the vehicle.

Your garage, a private driveway, a parking space in a supermarket are perfect. Make sure you work in a ventilated area. In a garage, leave the gate open


by disconnecting the battery, you will reset the clock, the radio, the on-board navigation system and the alarm. Before you act, make sure you have all the reset codes. Check the vehicle booklet for this information.

Step 2. Lift the hood to access the battery

Remember to equip yourself, because a battery contains sulfuric acid (electrolyte), dangerous acid if there is one. It is both corrosive (on metal and skin) and in the open air, it gives off toxic vapors and flammable gas (hydrogen). Work safely by putting on fireproof gloves and wearing eye protection. Lift your hood and possibly make it hold with its kickstand.

  • To avoid being a conductor, remove any metallic object (rings, bracelet, watch) from your fingers and wrists.
  • Wear old clothes that you don't mind getting dirty.
Change a Car Battery Step 3

Step 3. Locate the location of the battery

Usually, it is on the side of the engine compartment and in the upper position. It is a kind of plastic cube, often black, with two cables coming out on top, one black, the other red. On some models, it is under a cover that must be lifted.

  • If you really can't find it, refer to the manufacturer's manual.
  • The battery is often in the engine compartment, but sometimes it is in the trunk or under a back seat.

Step 4. Undo the negative cable first

It is a fundamental question of security. This cable is black and is attached to the negative terminal of the battery (a "-" sign is stamped on the lead). Lift the protective cap off the terminal. With a wrench (open or socket), loosen the fastener bolt, then disengage the cable from the terminal. To prevent this somewhat rigid cable from coming back to touch its terminal, secure it temporarily to the side with a plastic cable tie.

  • Use one of these small plastic cable ties (serflex) to hold the cable to a nearby part. The cable must not come back to touch its terminal, or even a metal part.
  • The fixing nut can be removed with a 7, 8, 10 or 13 wrench. Some somewhat sophisticated batteries have terminals which are in a way clipped: they therefore have no bolts and can be removed without tools. the hand therefore.

Step 5. Then undo the positive (red) cable

It is on the other terminal (this time, marked with a "+" sign) and comes apart in the same way: lift the cap (if there is one), undo the nut with the 10 wrench and secure the cable with a plastic cable tie (a piece of string, this also works) on a non-metallic fixed part.


the two ends of the cables must not touch each other, nor must they touch any metal part.

Step 6. Remove the battery from the vehicle

In general, a battery is fixed on its bottom support by means of a small jaw (at the bottom of the battery) which is held by a nut of 13. To undo it, you need a somewhat long pipe wrench. Fully remove the battery by hand or using a battery strap. Place it on a hard floor.

A battery is certainly small, but it is heavy, possibly get help with transport

Part 2 of 2: install a new battery

Step 1. Clean the battery terminals

Over time, these terminals become covered with a white, green, gray or blue deposit: this is slightly acidic corrosion. Put on gloves and goggles, then clean both of your pods with sandpaper, a wire brush, and baking soda. Try to find the shiny appearance of the lead.

This corrosion powder is certainly aggressive, but without any real danger. Gloves and glasses are there to avoid inconvenience

Change a Car Battery Step 8

Step 2. Buy the correct battery

There are many, many batteries, each designed by the manufacturer. You should therefore purchase a battery that exactly matches (in size, voltage and amperage) to the recommended one. If you buy it from your dealer or a spare parts store, don't forget your registration card. In supermarkets, consult the plastic sheet for the battery section.

  • Regardless of the brand of battery (even if the one sold by the manufacturer is ideal!), What matters is that the specifications are the same as the old one (dimensions, voltage and current at the terminals).
  • Both polluting and so interesting, a battery cannot be thrown away just anywhere: it must be recycled (lead). Many solutions free are available to you: drop it off at your recycling center, leave it at a garage or dealer, or at the one who sold you the new battery.
  • All of these collection points are required by law to accept your battery. In general, there is never a problem. At the recycling center, ask the caretaker in which specific container you should drop it off, because these are special types of waste.

Step 3. Install the new battery

Position it identically to the old one. Secure it to the foot with the 13 nut. Before fixing the battery definitively, pay attention to the orientation of the terminals, otherwise your cables will not go. Once done, grease the two terminals with contact grease (protection and better conductivity) available where you bought the battery.

  • Look at your cables, one is longer than the other and orient your battery so that these cables can come to cover their respective terminals.
  • When this work is done, (gently) shake the battery to make sure it is secure, it would not be moving due to vibration.
  • Grease (usually lithium) should only be deposited on the terminals and nowhere else on the battery or motor.

Step 4. Reconnect the positive cable

While holding the cable so that it does not touch anything metallic, cut the cable clamp, then engage the terminal on the terminal marked "+". Push it all the way in, then retighten the nut without forcing too much, but still firmly. Put the cabochon back in place if necessary.


the reassembly of the cables always starts with the positive cable (red) in order to avoid a short circuit. In this case, the circuit is always open and therefore safe.

Step 5. Reconnect the negative cable

Do with this second cable, exactly what you just did with the first … and with the same precautions. The black cable is inserted into the “-” terminal of the battery. Push in the terminal all the way, tighten the nut and replace the protective cap. Here is ! Remove the excess grease with a cloth, it is no longer useful now.

If your battery is protected by a general cover, replace it now as it was previously

Change a Car Battery Step 12

Step 6. Lower the hood and attempt a start

Before closing the cover, check that everything is in order, no parts, no tools and no rags should be lying around. If the cause of the failure was really the battery, you should see all the lights on the dashboard come on and start successfully. Enter the secret codes to operate your various on-board devices.

Check that all these electrical devices are working properly, reset the correct time, check the on-board computer


  • Wear old clothes that you don't care about.
  • On certain vehicles, the battery is in the trunk, not under the hood.
  • Some large vehicles have two batteries placed in two different places.


  • Always put your battery correctly, that is to say the terminals up, not on the side or worse… upside down!
  • Avoid working in rainy weather.
  • Before working, remove all your metal jewelry (rings, curb chains, etc.)
  • Never put the two terminals of a battery in direct contact.
  • Wear protective goggles and flame retardant gloves.
  • Never place a metal bar, such as an open-end wrench, on the battery which would bring the two terminals into contact: this will ensure the short circuit.

Popular by topic