Your car battery will probably have a metal plate on it indicating the year it was put into the car. This plate services the purpose of letting you know when it is due to be replaced as batteries for cars are recommended for use for a certain number of years only, perhaps one or two but some are for longer. If the battery is not replaced to time, it can become old and therefore not so efficient. It lack of efficiency will start to show by it taking longer to re-charge which means that if you stop and start the car a number of times without allowing time for the battery to re-charge fully, it may no longer start the car. As the battery gets older it increasingly charges at a slower pace, allowing for potentially more starting problems to occur but at this stage at least the battery is still charging, just that it probably does not hold as much charge as it used to and so, it may not have caused you problems in you have been driving your car in a regular manner. As the battery continues to get older though, it will eventually refuse to accept a charge and therefore totally run out of power, leaving you unable to start the car and if you do jump start it, as the battery will charge itself from the engine, you will have to continuously jump start it until you replace the battery. From experience this can be very disturbing if you are driving your car with the battery in this stage and then stall at the traffic lights.
If the car does not start right away from your battery and your battery is still relatively new, the battery could either be damaged or the alternator on the car is not working properly. The battery’s purpose is two-fold, it initially starts the engine by turning it over which takes a good bit of charge but then, once the car has successfully started, the battery continues to operate all the electrical devices the car may have, such as the lights, stereo, windshield wipers, automatic windows and horn although these do not use as much current as the initial starting of the car does. The alternator on the car transforms the spinning engine into electrical current which it passes on to the battery to either re-charge it or store it once it is fully charged. If the alternator is working properly and efficiently, it will supply more current to the battery than the battery is using operating the electrical devices and so should leave the battery with enough current to start the car next time is needed to.
Obviously then, a battery needs to be replaced regularly and to time and you can check Car Batteries online to see which is the correct battery for your car as they come in various sizes, plus various amounts of power and you must get one that not only fits the space provided for holding the battery but also ensure that it has enough power to start the size of your car’s engine.