Photo 1: Set voltage selector to battery size
Set the voltage selector to the 1.5V setting (1.5 volts) and touch the red probe to the (+) end (with the nub) and the black probe to the (-) end of 1.5-volt batteries.
Multitester readout for 1.5V battery
Read the battery test scale. Red is bad and green is good. This battery is bad.
Photo 2: Testing a 9V battery
Set the voltage selector to the 9V setting (9 volts) and touch the red probe to the smaller (+) connector and the black probe to the larger (-) connector (as marked on the battery label).
Readout for a good battery
The indicator is in the green area, which means this battery is still good.
Multitesters have many uses, and one of the handiest is testing common household batteries. A weak or dead smoke alarm battery in a fire, or a dim flashlight bulb during a blackout, can be downright dangerous. Pull out that multitester and check those vital batteries so they're ready when you need them.
Insert the black probe into the (-) terminal, and the red probe into the (+) terminal. Rotate the voltage selector switch until it points to the voltage you're testing, and then test batteries as shown in Photos 1 and 2.