Car battery buying guide

Are you in the market for a new car battery? Well, you’ve come to the right place.

This guide will help you find a replacement if yours is on the way out, along with some tips and tricks on how to make your current battery last as long as possible.

What is a car battery?

A car battery is a rechargeable battery that provides your car with electricity for various functions. It’s a plastic box with two connection points that connect to your car’s electric system. It will also often display a sticker with its manufacturer information and the number of years it’s covered under guarantee.

How do car batteries work? 

A car battery provides the jolt of electricity needed to power all the electrical components of your vehicle. So even though it looks small, the power it provides is pretty huge. Let’s take a look at how the little box works:

  • It’s a chemical reaction that gets your car going. When the key is half-turned in the ignition, the reaction takes place, converting chemical energy into electrical energy to power your car, with the battery delivering voltage to the starter.
  • The battery is also responsible for keeping your car engine running. By keeping the electric current steady, it’s also stabilising the voltage (that’s the term for the energy supply). 

Over time, the battery will lose its charge but, luckily, the reaction can be reversed – meaning energy can be stored in the battery by charging it.

What do car batteries do?

As mentioned, the battery is responsible for some vital jobs, and without one, you won’t be going anywhere!

  • Starting – when you half-turn your key in the ignition, your car battery is there to help your car wake up. You can put on your air conditioning, turn on interior lights, check your dashboard lights and play your tunes without having to turn the engine on. That’s all being powered by your battery so it’s important you don’t do any of these things for an extended period without the engine on, as you’ll soon run out of charge!
  • Lighting – all of your lighting runs off the battery; that includes interior lights, indicators and rear and main headlights. On top of this, car batteries power the other electrical items that can be fit into your car or plugged into a 12V outliet – for example, sat navs, phone chargers, or even mini fridges!
  • Ignition – of course, your car needs electricity to get going, and your battery will provide the spark needed to make it run.

    What battery do I need for my car?

    Choosing the right battery will help ensure your car performs as well as it should and minimise the risks of costly breakdowns.

    Each battery has a three- or four-digit code, such as 075 or 096T. This code indicates the size, power rating and terminal positions of the battery, amongst other things, and helps you find the correct replacement battery for your car.  Meanwhile, the size of battery you choose will depends on several factors, such as where the terminals sit and the space that’s available under the bonnet. 

    As a general rule, we would suggest fitting the same type and size as the manufacturer’s original. A quick look at the owner’s manual will hopefully give you all the information you need. Additionally, Autoparts has a tool that lets you enter your registration number to find the correct battery for your car. Check it out here.

    The main types of car batteries

    Car batteries come in various sizes and types, and so there isn’t a ‘one size fits all’ approach. Though the traditional lead-acid battery is still commonplace, different cars require different battery types depending on their on-board systems. Check out our full range here.

    • Lead acid batteries are the oldest type of rechargeable batteries. They’re also one of the most common batteries found in vehicle. Importantly, they’re durable and easy to replace.
    • Calcium batteries are a derivative of the lead acid battery. They offer a bit more starting power and durability and are also known as ‘wet lead acid’ batteries. They also have a good shelf life and they’re maintenance-free, but they do require regular use.
    • Yuasa silver batteries are top-end calcium batteries that are often required for high performance vehicles. With a 5-year guarantee and offering up to 50,000 starts, you can get an additional 33% starting power compared to an ordinary battery.
    • AGM batteries are versatile and designed to cope with the high demands of modern vehicles. They’re more expensive than other options, but, unlike wet lead acid batteries, they have no fluid, meaning they’re leak-free, spill-proof, and maintenance free. They have a higher durability and greater cycle life than ‘wet’ batteries. They have excellent starting power, even at low states of charge, and recharge much faster. AGM batteries are also ideal for vehicles with automatic stop/start systems as traditional batteries can’t handle the high-power demands of these systems. 
    • EFB batteries have similar qualities to the AGMs in that they charge rapidly between starts and are more durable than standard ‘wet’ batteries. An optimised version of the ‘wet battery’, they are used in vehicles with simple stop/start technology. Some car manufacturers often use them as a cost-effective alternative to the AGM or as an upgrade from the conventional lead acid batteries.

    How long do car batteries last?

    There’s no definite answer to this, but generally, a car battery will last for around three to five years – with the higher end calcium batteries usually lasting longer. There are several factors that can affect this, such as temperature extremes, taking regular short trips, long periods of inactivity, vibrations from rough journeys and the number of electronic devices, like sat navs and smartphones, that join you on your drives. For example, batteries in cars driven mostly on short trips may not fully recharge and batteries in vehicles parked for extended periods naturally self-discharge.

    How long do electric car batteries last?

    Most electric vehicles use lithium-ion batteries, so they also naturally degrade over hundreds of uses. They’re slightly different to traditional car batteries in that EVs depend on their battery to get from A and B, instead of fuel.

    However, drivers can expect upwards of 10 years or 100,000 miles of use – with reports of twice that distance. This, of course, can be affected by a number of factors, such as extreme cold or hot temperatures, overcharging or using the battery’s minimum capacity. 

    Battery degradation won’t affect the EV’s performance, but it could potentially lessen the range over time.

    How do I charge a car battery?

    Not sure how to charge your battery? Autoparts has a range of battery charging products that can come to your rescue. Even if you jump start it as a quick fix, it’s always good to look into charging it properly so the battery stays in good condition.

    • Firstly, check what kind of battery you have. If your car has stop/start technology, you’ll have an AGM or EFB battery. A conventional charger won’t work for these and you may need a ‘smart’ charger instead. If you’re unsure, feel free to contact us and we can send you in the right direction.
    • Check the contacts – if your lead terminals or clamps look dirty or corroded, you should give them a clean before charging.
    • Disconnect your battery – to avoid a shock, disconnect the negative lead first and reconnect it last. Undo the terminals (negative first) and move to one side. Remember, when you disconnect your battery, you may need to reset your radio and dashboard.
    • Connect the charger – make sure the charger is as far away from the battery as is possible, and don’t leave the charger on top of the battery while it’s charging. Connect the clamps of the charger to the terminals on the battery, matching positive with positive and negative and negative. Next, plug the charger in.
    • Turn on the charger – some chargers will turn off automatically when the battery is charged, but others will need to be disconnected. Check the manual for your charger to find out how long it will take and what you need to do. If you’re using a smart charger, it may tailor the charge cycle to fit to avoid overcharging.
    • You’re charged! Once the battery is charged, unplug the charger and then disconnect the clamps. Then, reconnect the car battery (positive first and negative last, remember!) and away you go!

    How do I look after my car battery? 

    Regular car maintenance can extend the life of your battery and save you money in the long term. A smart charger can repair existing issues, as it charges and can help prevent any further damage, so by using one regularly, you can avoid having to buy another battery sooner.

    Otherwise, we’d recommend giving it a visual check now and again and cleaning it every few months to keep it in good shape. Of course, try and remember to turn off your lights and avoid running electrical functions with the engine off, as this may cause it to drain quickly. Similarly, don’t leave your car stationary for long periods of time.  

    How do I know if my car battery needs to be replaced?

    There are various signs that your car battery could be on the way out. For example, if you notice that the engine is cranking a bit slowly or if it’s taking longer for your car to start, this can be a warning that the battery may be about to die. If you hear a click when you start the engine, it could possibly mean you don’t have enough to power to crank the engine, in which case you’ll need a jump-start.

    Another sign is losing power to electrical systems, like your windows, lights and heaters, but the most obvious sign your battery is nearly done remains the illuminated battery symbol on the dashboard. If you notice any of these signs, it could be worth booking your car in for an appointment with a technician. They may be able to fix the issue, or you may need a new car battery. Either way, it’s better to act sooner so you don’t end up stranded at the side of the road.

    How do I replace a car battery?

    Not everyone is mechanically minded, so if you aren't confident replacing a battery yourself, seek professional help and advice from a garage which is accredited to do the work.

    If you are feeling up to the challenge, then follow the steps outlined above to disconnect your old battery. Then, to fit your new battery, simply place it into the cage and reverse the removal process, connecting the positive terminal first, then the negative. It is likely that you will now need to reset any electricals inside the car – such as the clock or infotainment system.

    How do you dispose of an old car battery? 

    If your car battery needs to be replaced, you’ll have to safely dispose of it. It’s illegal to just throw it in the bin, so you’ll have to safely remove it and recycle it – usually with the help of trained professionals from a recycling service. 

    Looking for a new battery? Shop car batteries here

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