Turn off the device and remove the battery if needed
Set the voltmeter to DC voltage
Select a voltage range above the battery’s rated voltage
Touch the red probe to the positive terminal
Touch the black probe to the negative terminal
Read the voltage on the display
Compare the reading to the battery’s rated voltage
Check for a low or dead battery if the voltage is significantly below normal
Test under load if you need a more accurate result
Replace the battery if the voltage is too low for proper use