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How to charge a car battery

Stephen Wright, 1 year ago

4 min read

  • Advice
  • howto
Car Battery Test

A step by step guide to charging your car battery from WhoCanFixMyCar

Car batteries can go flat for a whole host of reasons, and while jump starting your battery is a quick and easy fix, if the problem persists, save for a replacement, then it is often advisable to invest in a battery charger to ensure it remains in the best possible condition.

Not quite sure exactly how to charge a car battery? Don’t worry, you're not alone. Our guide has the answers you need to get you powered up and back out on the road in no time.


Why do batteries go flat?

How to check which type of battery you have?

How to charge your battery?

Why do batteries go flat?

  • Too many short journeys don’t give the battery time to fully recharge

  • Overuse of devices when the car isn’t running

  • Leaving headlights or interior lights on overnight

  • Extreme temperatures (both hot and cold)

How to check which type of battery you have

Before you go rushing off the shops to buy yourself a battery charger, make sure to check what kind of battery you have. There are two types of chargers on the market:

Standard Chargers - if you’re looking for simple and straightforward charger (and you’ve got a lead acid battery) to get the job done then a standard is ideal. Please note they aren’t suitable for vehicles with stop/start technology

Smart Chargers – Smart chargers are designed for AGM or EFB batteries and tend to be a lot more technologically advanced, enabling them, for instance, to charge in stages for more efficient charging as well as switching to a trickle charge when your battery is full to avoid over-charging.

How to charge your battery

Check your contacts

Once you’ve bought the right charger, it’s worth looking at the battery terminals and the clamps that connect them. If they look dirty or corroded make sure to clean them before recharging.

Disconnect your battery

It’s always advisable to disconnect your battery before you begin charging. However, before you do that make sure you have your PIN code to hand as you may have to reset things like your car electrics when you reconnect your battery.

Always disconnect the negative (black) lead first and reconnect last - otherwise you might get a shock when you touch the negative terminal. Next, undo the terminals (negative first) and move to one side.

Connecting the battery charger

Once you’ve disconnected the battery it’s time to start charging. Simply connect the charger clamps to the terminals on your battery, matching positive to positive and negative to negative. Only then plug the charger into the mains.

How long should you charge a battery?

This will depend on the type of charger you have. If it’s a standard charger then always consult the instruction manual to find out how long it will take. With smart chargers, these will assess the condition of your battery and automatically switch over to what’s known as a ‘maintenance charge’ to avoid overcharging once your battery is full charged.

And that’s it. Simply unplug and disconnect the charger clamps. All that’s left to do is reconnect the car battery (positive first, negative last) and you are done.

Obviously, if problems persist with your battery, we would recommend speaking with a professional as it may mean that your car needs replacing.

WhoCanFixMyCar can help by connecting you with garages in your local area. Click on the link below to compare prices on a range of new car batteries from the garages closest to you.

Compare Car Battery Prices
Get a quote now!

Suggested reading

Still want to know more about batteries? Then why not check out the following guides:

Where is my car battery located?

How long does a car battery last?