How to charge a Car Battery
People often ask why their car battery is flat, how to charge a car battery, and does it need replacing, so we’ve put together some information to help answer your questions.
Why is my battery flat?
During lockdown many cars will be parked up for long periods of time and many journeys will only be short ones. This could result in your car battery losing charge and you might find it difficult to start your car.
If you are not using your car regularly, we recommend that you start up your engine every couple of days and let it run for a while, please stay with your car while the engine is running.
Car batteries can also lose charge if you leave your exterior or interior lights on while parked and both can quickly drain your battery. Using a Sat Nav, charging phones and other electrical gadgets can also drain your battery.
Batteries can also lose charge in the cold weather, especially older batteries. Batteries don’t last forever like many other components in your car. They naturally lose charge with age, so it may just be time to replace it.
Sometimes batteries go flat if there is a fault with the alternator. If the alternator isn’t working properly it won’t charge the battery, so get this checked.
If you don’t charge your battery frequently and for sufficient distances, your battery will eventually go FLAT!
Related: How long do car batteries last
How do I get my car started?
In many cases, you may need to jump start your car to get it going, but in order for the battery to charge you would need to do some miles to top it up. In many cases just driving your car isn’t enough and the car battery may need to be charged using a battery charger.
Related: How to jump start a car
Many vehicles today have stop-start technology and batteries for these vehicles are different, which are either AGM or EFB batteries. Battery chargers for stop-start cars are different so please remember to check you have the correct battery charger.
How do I use a battery charger?
Before you use a battery charger it is best to disconnect the battery and you need to make sure the terminal leads and clamps are clean. They often get very dirty and corroded under the bonnet. If you do not remove the dirt or corrosion you may not get a proper connection. Disconnect the black negative lead first, then the positive lead. When reconnecting please make sure to leave the negative lead to the last, so you don’t get a nasty shock.
You may lose some dashboard settings when you disconnect the battery, including the radio settings, so make sure to have your security code to hand, so you can reset these.
When you are ready to start charging, please do not sit the charger on top of your battery, the leads are usually long enough to sit the charger on the floor. Connect the charger clamps to the battery terminals, making sure to match negative with negative and positive with positive. Once you are set plug in the charger and turn it on. Some battery chargers will switch off when the battery is fully charged, please check the instructions for your charger.
When reconnecting the leads, please check they are tightly fitted.
Battery still not charging?
Charging your car battery may not totally solve your battery problem and your battery may lose charge again, which could indicate the battery needs changing. If this happens, we would suggest you get your battery tested as soon as possible.
All our branches offer FREE Battery Health Checks and our technicians have the latest testing equipment. It only takes a few minutes to complete and we can provide a printout of the test results.
- If the battery test result is ‘GOOD BATTERY’, then you would be recommended to have a re-test in 12 months time, providing your driving conditions remain the same.
- If the battery test result is ‘GOOD RECHARGE’, this means the battery is in good health but needs a good recharge. We recommend a 45-minute motorway journey at up to 70mph and a re-test in three months time, to make sure the battery is still in good health.
- If the battery test result is ‘RECHARGE AND RETEST’, this means your battery has insufficient charge and will need to be recharged ASAP, then retested in 7 days.
- If the battery test result is ‘REPLACE BATTERY’, it indicates that the battery is no longer providing enough power to start your car and will need to be replaced.
Related: How to test a car battery
For great deals on batteries, simply enter your registration number into the search box at www.national.co.uk/batteries. All our prices include fitting and there are no hidden extras.
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