It happens to the best of us. We leave the radio or the lights on in the car overnight and wake up the next morning to find that the battery has gone flat just at the moment when we most need the car. If your battery does go completely flat, then you will need to charge it. You can do this in one of several ways.
How to charge a battery
- Disconnect the battery. If you can, it is best to remove the leads from the battery but this is not always possible. If not, unplug the negative cable. Nb. When you cut the power source to some of the electrical elements to your car, they may require you to enter a code when the battery is reconnected. You should have all of these codes in your car instruction manual or with the documents to the car. If you do not have them, you may not be able to use your radio, clock etc. until these codes are entered.
- Attach the charger. Not all car batteries are the same and will therefore require different chargers to do the job properly. Before you connect anything, make sure that the charger you have is appropriate for the battery in your car. Once you are sure that they are compatible, follow the instructions on the battery charger packaging to connect the wires correctly. Make sure that the charger is not switched on at the mains whilst you do this. You will usually find that you need to attach the charger’s red clip to the positive terminal and its black clip to the negative one.
- The next step is to switch the charger on at the mains. It will depend on the battery charger which you have purchased, but usually a green light will come on to say that the charger is switched on and working. If there is no signal to say that it has been switched on then you should switch it off at the mains and recheck all of the connections. If you have not connected the clips and wires correctly then the charger will not work and you could seriously damage your vehicle’s electrical system.
- Each battery charger is different but all of them will have some sort of indicator to let you know when charging is complete. This could be a light going off, a second light coming on or a light changing colour. The battery charger instructions will let you know what to expect. Once this signal shows, it is extremely important that you disconnect the charger from the mains before you remove the clips from the battery itself.
- Then all that remains is to turn the ignition and to see if the car starts. If you are not going to be driving the car straight after charging, then it is probably worth testing the battery charge levels 12 hours later to make sure that there are no problems with the battery itself.
What if charging the battery fails?
If charging the battery doesn’t work then there is likely to be a much more serious problem with it. You will probably find that you need a new battery altogether. You can either choose to replace this yourself (being extremely careful not to damage the vehicle’s whole electrical system) or you can take your vehicle into a workshop and get a professional to fully diagnose the problem.
Jump starting and driving
If you need to be off in a hurry and don’t have the time to fully charge your battery, you can jump start your vehicle by connecting it to someone else’s. This is a very simple process as long as you have a set of good quality jump leads in your car.