27th March 2022

What to do if you have a flat car battery

Flat car batteries are one of the most common reasons drivers breakdown. Here we look at the steps you need to follow to check the health of your battery and replace it when the time comes.

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One of the most common reasons a car breaks down is due to the battery going flat, but how do you stop this from happening, how long does it take to charge your car battery and what are the signs that it’s on its way out? We explain everything you need to know in this blog.

What causes a battery to go flat?

A flat battery can be caused by a number of things, including the following:

  • Leaving your car lights on
  • A faulty battery
  • A fault in the electrical system
  • Corrosion and cold weather
  • General wear and tear

If you find that your battery is flat, it could be time to buy a new one, or inject new life into the old one. 

Should I jump start the car or change my battery?

flat car battery

In the long run it’s better to recharge the battery, but in emergencies a jump start may do the job to get you to your destination. When jump starting a vehicle you are boosting the engine’s failing battery with a second battery, usually on another car. You connect the jump leads to the two battery terminals positive to positive and negative to negative. Learn how to do the full process in our guide to jump starting your car.

With the booster car’s engine running at a fast tick over, you allow the failing battery to take a little boost charge and the car should be able to start. The battery should begin to charge itself while the engine is running. 

If you’ve broken down on the side of the road, or your car won’t start at home thanks to a flat car battery, our instant breakdown cover ensures you can get up and running again.  

How much does it cost for a new car battery?

The price will vary depending on your vehicle and the size of battery it will need. Usually you can expect to pay in the region of £50-£200 at a reputable retailer. Make sure you do your research and speak to a professional either at a garage or a retailer to make sure you are buying the right battery for your car and you’re not getting ripped off.

How to change a car battery

Before you start, there are a few things you should be aware of. Make sure that you never change a battery during wet weather, and remember while a 12V battery will not shock you through your skin, there are still safety steps you must adhere to to make sure you remain safe. You must also avoid the two terminals from touching anything metal, as this can cause sparks and heat. 

If you are uncomfortable with changing the battery yourself, it is best to get a professional to change it for you at a garage or a retailer such as Halfords.

  1. Undo the clamp nut and remove the cable connected to the negative terminal first
  2. Repeat the same process for the positive terminal 
  3. Undo the battery bracket or the hold-down clamp and simply lift the battery out. Be advised batteries can be heavy
  4. Make sure the battery tray is clean before adding your new battery
  5. Place in your new car battery and fix the bracket or hold-down clamp
  6. Now it’s time to secure the cable. Make sure you attach the positive cable first before the negative one 

How long does it take to charge a dead battery?

Usually it will take between an hour and a full day to charge the battery, depending on how flat the battery is and the state it is in. It also depends on what type of battery your car has, and the mode of charging you choose.

Can a completely flat battery be recharged?

If the battery is your only problem and the car is in otherwise good working order, it is quite possible to recharge a completely dead battery.

How long can a car run on a flat battery?

If the battery is not faulty and the car is in good working order, you need only drive for half an hour or so to give your battery an adequate charge. However, you should always seek to buy a battery and change it at home or get an expert to do so. 

A battery can let you down any time, but Sterling won’t

Contact Sterling for all your motor insurance needs. The best deals do not appear on price comparison sites and are usually only available over the phone so call 0344 381 9990 to find out how much you could save.

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