So, your car battery has died… and you know that you need a new battery, but you can’t work out which battery that you need? This is the guide for you.

Step One - Check existing battery for any codes

You may find that your existing battery is printed with the UK part number. In most cases this is a three digit code such as ‘063′ or ‘096′. If you have this code then you have everything that you need in order to purchase a replacement battery. Simply type the code into our ‘Product Search’ box on the right hand side of any website page in the following format: ‘063 Car Battery’ replacing 063 with your part number. If you have the right code you should see the search results pop up in the centre of the page.

Step Two - Fitment Guides

If your current battery doesn’t have a UK part number printed, don’t worry. The first port of call in this situation is to check our excellent car battery fitment guides. The battery manufacturers provide us with a list of models that each battery may fit. The fitment is by no means a guarantee, but this should give you a good idea of which is the correct battery for your vehicle. Compare your current battery to the battery that our guide suggests in the following manner:

• Compare dimensions. Our measurements are all LxWxH and are in millimetres. (Remember that our measurements are to the most extreme parts of the battery, so the height is to the top of the terminals etc.)
   
• Compare the terminal layout. (Where the positive and negative terminals are located). For some reason many people find this a difficult concept. Remember that you are looking at the front of the battery if the terminals are closest to you (first picture). It may be mounted in the car so that when you look at it you are looking at the rear (picture 2). Both of these images show the same layout, Positive Front Right. People often say things such as “I’m looking from the driver’s seat and positive is on the right”. This means absolutely nothing to us as we need to know where the positive is in relation to the battery, not the car!
   
• 
  Compare terminal type. There are four distinct terminal types all of which have very different properties so it is very simple to find out which you require. The standard UK type (picture 1) are easily recognised as they are extremely common. Measurements (at the base of the tapered terminal) are 17.5mm for the negative post and 19.5mm for the positive terminal. Japanese terminals (picture 2) are visibly narrower at 13.1mm for negative post and 14.7mm for the positive. Lug terminals (picture 3) are square bolt-through terminals usually fitted to pre-1996 Ford vehicles. Finally, side terminals (picture 4) are easily recognised as they are on the side of the battery!

If the battery selected by the fitment guide matches all of these criteria, you have checked all that you need to to confirm that it is a suitable battery for your vehicle.

If the suggested battery does not match any of the above criteria, or your vehicle is not listed in our guides, you need step 3, the Battery Wizard.

Step Three - Our Car Battery Wizard

Our car battery wizard has been designed to take any information that you have about your existing battery and tell you what it is. You will need to have the dimensions, terminal layout and terminal type to hand before proceeding.

• Fire up the car battery wizard in your browser.
• Enter your dimensions in millimetres into the first section.
• Leave the ‘Capacity’ section blank.
• Choose your terminal layout from the pictures shown.
• Choose your terminal type from the pictures.
• Click ‘Find my Battery’.

The wizard will compare the detail that you have entered to all UK batteries. The dimensions will be compared +/- 10mm which usually gives a result. If your search returns no matches, you are given the option to search +/- 20mm, then 40mm and so on until a match is found. If you still can’t get a match, you have either taken down your measurements incorrectly or selected the wrong terminal layout or type.

Once you have found the battery, again compare this to the data you have collected from your existing battery to confirm fitment.