How to test car battery with multimeter
Car batteries provide electricity when the engine is not running. It's used for starting, lighting, ignition, etc. Without a good battery, you cannot start your engine. So, how do we know if the battery is good or bad?
Test it, and to test a car battery, we need a common tool called a multimeter. Yes, using a multimeter to test car battery can be a good choice to see if the car battery is in good condition or not.
A multimeter is a standard tool to check and test a car battery. A multimeter can measure the battery voltage. We can see if the battery is good or bad with that tool by measuring the battery voltage.
So, how to test car battery with a multimeter? Here's how to do :
I. Set the multimeter to measure the battery voltage
Set the multimeter to DCV mode to measure the battery voltage. Common car battery voltage range is between 0 - 13 Volt DC. So, to test a car battery with multimeter is we have to set a higher range from the battery voltage.
To do that:
- Turn the selector to pointing at DC voltage. If you are using an analogue multimeter, turn the selector to 20 Volt DC.
- Remember, a common multimeter has two pointing voltage selectors. The first is AC voltage, and the second is DC voltage.
- Choose the DC voltage to test a car battery voltage.
II. Attach the multimeter to the battery
Attach the multimeter to the battery to measuring the battery voltage. Here's how :
- Put the red probe test lead from multimeter to the positive battery (the positive battery usually marked with + (plus) sign or with red cable terminal)
- Put the black probe test lead from multimeter to the negative battery (the negative battery marked with - (minus) sign or with black cable terminal)
- Read the battery voltage on the multimeter display. If you're getting a reading with a minus value in front of it (-12.6 rather than 12.6), then you've got the probes the wrong way round!
- Last, compare your multimeter reading to this table:
| Battery condition | Voltage range |
|---|---|
| Fully charge (Good) | ⩾12.6 Volt |
| Fair to use | 12-12.5 Volt |
| Low voltage | 11.8-12 Volt |
| Discharge | ⩽11.8 Volt |
Suppose the reading voltage shows a value of 12.60 Volt or more. In that case, this means that your car battery is in good condition because this is the state of fully charged car battery voltage. But if the reading value is below 12 volts, this means that your car battery is already in low voltage or in discharge condition.
Discharge conditions hold two or more causes, but mainly are charging system failure or signs of a dying battery. Just read the blog post I've been made below for the dead battery and the reasons why the car battery won't recharge
For safety reasons, always use rubber gloves and goggles whenever you service your battery. It will protect your hands and eyes from acid.