28/08/2016
Checking the alternator is a relatively simple process, so it’s the kind of task that you could add to your maintenance routine – whether you check the condition of your car and the levels of your fluids weekly, fortnightly or monthly. To start with, open the bonnet and locate the alternator, which is connected to the battery.Take a multimeter and set it to around 20 DCV. Then connect the negative terminal on the battery, followed by the positive terminal, and this should give you a reading. Anything around the 12-volt mark would be desirable in this case. At this point you can then start the car and this will test the performance of the alternator. When the engine starts the voltage displayed on the multimeter should increase to around the 14-volt mark – anything above this could cause damage to the battery by giving it too much power, while anything below this would indicate that it isn’t being charged sufficiently. You should then switch on any additional electrical parts in the car – such as headlights, the radio and interior lights – as this will affect the voltage reading. Again, if this drops below the original 12-volt mark then it may mean that the battery isn’t being charged by the alternator.
