How to check a car battery with a multimeter.
Check car battery with multimeter uk.
I have always advocated for a reliable multimeter to be one equipment that should always be in the toolbox.
In this video i make some simple tests using a multimeter and establish that the battery in my wife s car is faulty and that the alternator is good.
Set the dial to 20 which will allow you to accurately measure between 0 20 volts.
Set the multimeter to 15 20 volts.
Any reading of voltage below 9 5 volts or if the battery holds a good record for a while and steadily drops or even when it falls instantly to 0 volts then it means there is a problem and the battery.
Turn the headlights on for two minutes to get rid of any surface charge the battery may have.
You can use a multimeter to find out if your battery has enough charge.
How to check car battery with multimeter.
Testing a battery with a multimeter is a simple process.
Testing a car battery using your digital multimeter testing the voltage.
The first test with your multimeter will measure dc voltage indicated with a solid line and a dashed line above a letter v.
For your battery to pass a load test the multimeter must read between 9 5 to 10 5 volts straight for 30 seconds when the battery is tested.
So one of the primary diagnostic uses of a multimeter is to check the battery voltage in a car that is having problems starting.
On some car models the voltage of the battery can be checked at the dashboard but that won t help you know how good is your battery since the voltage reading in the dashboard actually shows the power coming from the alternator and not the battery.
Car batteries are 12v affairs but a fully charged battery should be expected to read above 12v.
Your battery may be failing but for you to be sure you need to know how to test a car battery.
Most people have experienced or at least know of someone whose car did not start due to a low battery charge.
The first thing to do is make sure you can access the two terminals on the top of the battery.
Touch the red probe to the positive terminal and the black probe to the negative terminal.
Turn the lights off.
With the headlights on at 80 f there should be a voltage drop of at least 11 8 volts 25 charged and ideally 12 5 volts between the positive and negative terminals.
How to test a car battery.
