How to fix a dead car battery?

By Julia Freeman

A dead car battery is one of every driver's worst nightmares, but it's a problem most of us have had to endure at least once.

mechanic changing car battery

Flat batteries can seem like a major inconvenience, but you don't always need to purchase a new one just because the car won't start. There are plenty of reasons (lack of use, cold weather, age of the battery) that your battery might be dead, but there are two main ways that you can hopefully bring it back to life.

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Jump starts

Jump starts are the best way to kickstart a dead battery. Years of experience tell us that this is the first method you should try, and in most cases, it will get you back on the road. You'll need a set of jump lead cables and a power source to attach them to. Contrary to popular belief, you don't always need another car to perform a jump start. Hooking the cables up to another battery or battery booster can get the job done (although connecting to other vehicles remains the most common option).
Connect the jump leads to the correct battery terminals following the manufacturer's instruction, start the other car and then wait 3 minutes. With a bit of luck that should do the trick. Your car will start but that's not the end of the job. Let both cars run for another 10 minutes or so, on idle, before you disconnect the leads and get back on the road. Jump starts are usually successful but there are a few notes of caution. Never attempt a jump start on a frozen battery (there's a chance it could explode) and don't try it on leaking or damaged batteries.

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Slow charge

It's not always possible to jump start a battery, especially if the charge is incredibly low or next to nothing. In these cases, you might be best opting for a slow charge. Slow charges are actually better for long term battery health, but (as the name suggests) they take much longer. A slow charge can take up to 24 hours, so it certainly isn't the option when you're in hurry. Nonetheless, there are plenty of slow chargers available, and it's just a matter of connecting them to the right terminals then waiting. Again, do check the manufacturer's instructions.
There are several types of slow charger available. Linear chargers deliver a low amp charge over a long period of time, charging the battery slowly but surely. Multistage chargers are much quicker and deliver charge in short bursts, which is better for battery cells. Some drivers opt to keep their batteries hooked up to a trickle charger during the winter. These are no use for reviving a dead battery, but they deliver the low amps required to see a vehicle through the winter.

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Battery health is something that should be monitored continuously. Ensure that your vehicle's charging system is functioning correctly and consider a trickle charger over the winter. Vehicle maintenance, which includes topping up fluids, checking tyres and swapping worn tyres for quality replacements from manufacturers like Falken and Bridgestone, is essential. If you're concerned about your vehicle, our friendly mechanics at Protyre's local garages offer a free health check, which you can book online by clicking the button below.

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About the author

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By Julia Freeman
Julia is Head of Retail Marketing for Protyre and loves engaging with customers and the business as a whole to make sure Protyre is more than just a local garage.
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