I have noticed a few people have had problems recently with batteries and charging etc.
As it is fairly easy to check things yourself, with the right equipment, I don't like to see people forking out huge money to electricians (unless it is me
), I thought I would do a how-to so that anybody who wants to have a go, can.
I will add checking the alternator etc later when I next have the inspection cover off.
There are several methods to check the battery voltage.
One easy way is if your Hi Fi has a voltage display. I would only use this as an indication of whether the car is charging the battery, as the actual voltage is not very accurate (mine isn't anyway)
First of all, select the voltage display which depends on your head unit, mine is a Pioneer AVIC.
The Voltage is the right hand meter
Check the display with the ignition on, but without the engine running. In this case it says 11.5V. I know for a fact that the battery voltage is well over 12.5V, so it shows how inaccurate the display can be.
Now start the engine and check the voltage again. If the Voltage is the same or lower then you have a charging problem. The Voltage shoul be about 1V higher if correctly charging.
There are other quick and easy ways to check your battery. I bought this device from the bargain bucket at Halfords. Not exactly sophisticated test equipment, but gives you some indication of what is going on.
It is designed to simply push into the cigarette lighter and give you a visual indication of the state of the battery.
Once in the cigarette lighter socket you should turn the ignition on, but not start the engine. You might not need to do this if your socket is permanently live.
As you can see, my vans battery is healthy. Now start the engine and see what the reading says.
The reading has now gone off the scale, which shows the alternator is charging.
Now if you want to do a proper job you should use a decent multimeter and check at the battery terminals. This will give you a more reliable and accurate reading.
The meter I use is a Fluke, but most meters work under the same principle.
To check the voltage you should set the selector switch to Volts, then connect the red lead to V and the black lead to COM (common).
Connect the other end of the black lead to the negative terminal of the battery and the red to the positive terminal. You should now have a reading of around 12.6V for a healthy, fully charged battery. If it is below 12.4V then it may need charging. Anything below 12V needs recharging or a new battery. While connected, switch the headlights on and the voltage will drop but should still stay above 12V. Switch the headlights off.
Now start the engine and look at the reading. You should now have about 13.8V which will show that the alternator is charging a healthy battery. If the battery is flat, you will see and increase in Voltage, but it will not be as high as 13.8V until it becomes charged.
The picture below shows the meter connected for battery Voltage and it also shows that it is charging with a reading of 13.9V.
That is how to check your battery and charging.
I will add further basic electrical checks to this when I get the chance.