How to change a car battery (with video)

Always consult your car's user manual or the Haynes workshop manual for your vehicle's model for more specific information – not all methods will be exactly the same as this.  Be aware that by disconnecting your battery you may lose electronic settings for things like you're your stereo presets, your alarm and key fob settings – if in any doubt consult your car's manufacturer or take it to a professional!

Always ensure that the engine are other components are cool before carrying out any work under your bonnet!

Difficulty rating: 2

Tools required:

• Set of spanners
• Ratchet and 8" extension
• Socket set for ratchet
• Flat head screw driver
• Wire brush
• Baking soda
• Vaseline or anti-corrosion solution
• An old rag
• Surgical gloves - to protect your hands
• New battery

Step 1:

Buy the correct replacement battery. Never fit a smaller battery than the one originally fitted by the manufacturer. Consult your manual, check the label on your old battery, and/or tell the shop your car make, model and year to be sure that you are getting the correct replacement.

Step 2:

Ensure the engine is off and that all components are cool.

Open your bonnet and locate your battery. It will usually be clamped in place to one of the edges of your car's engine bay (the area under the bonnet!). It should be obvious because you will see the red and black battery terminals, but in some cars the battery will have aplastic cover over it, which will need to be removed first. (nb: in some older classic cars the battery can be located in the boot).

Step 3:

Once located, look at the two battery cables attached to the terminals on the battery.

Check that the cables are either labeled with a negative ("-") andpositive ("+") symbol, or are colour coded black and red respectively.

If they are not marked, it is advisable to label them now whilst they are attached to the terminals.

Later you do not want to be re-connect them to the wrong terminal as this can seriously damage your alternator and electrical system.

Step 4:

Now detach the negative (black "-") battery cable from the negative battery terminal.

First loosen the nut with the correct size spanner (or if space and access is an issue, use a socket and ratchet arm), then twist and pull up on the end of the cable to detach the clamp from the terminal – it may be easier to prize up the connection using your screwdriver.

Step 5:

Repeat the above step to detach the positive (red "+") battery cable from the battery.

Step 6:

Most batteries are held in place with a clamp. Using the right sized spanner or a socket and ratchet, undo the nut and bolt and remove the hold-down clamp.

Step 7:

With extreme care, take the battery out of the battery tray and away from the car. Batteries are heavy, so get a firm grip of the bottom using both hands.

Be careful of your back when lifting and lowering the batteries – they are heavy. Always bend your knees to support the load on your back, and never twist your spine when carrying the heavy objects.

If you have any existing back troubles get someone else to lift the battery for you, as you will need to bend forward whilst lifting and lowering it.

Battery acid is extremely corrosive and harmful. Take care not to splash it or spill any on your hands, body or clothing, or on car paint.

Step 8:

Using water, baking soda and a wire brush, clean any corrosion from the battery tray, the hold-down clamp and the terminal clamps.

Dry thoroughly with an old rag.

Step 9:

Before lifting the new battery, ensure you have the connections facing the correct way round for placing it back in the battery hold.

Place the new battery into the hold-down tray and re-attach the hold-down clamp.

Step 10:

Attach and tighten the positive battery cable to the positive terminal first. Then attach and tighten the negative battery cable to the negative terminal. 

At this point to prevent corrosion you can spray the terminals with anti-corrosion solution or smear on Vaseline.

Double check that all cable connectors are tight. If they are at all loose your car may not start, or you will experience problems later.

Step 11:

It is advisable to check the water level in your new battery.

Using your screwdriver, prize off the battery chamber cover on the top of the battery. You should be able to see the top of the lead plates of the battery and the water level should be at the top of these plates. Only use distilled water to top up these levels.

If you are in any doubt at all, consult the store you have just purchased the battery from.

Re-instate the battery chamber cover.

Step 12:

Check that you have removed all tools etc from the engine bay, and start the engine.

Close your bonnet, and that's it!

Car battery disposal

Do NOT dispose of the old battery with regular rubbish.

Either take it to a local authority waste disposal facility or scrapyard that accepts hazardous material for recycling, or you may be able to return it to the shop where you bought the replacement battery.