General Information
Battery History
Battery Timeline
Battery Types
Selecting a Battery
Battery Life
Charging Batteries
Battery Chargers
Charging Q&A
Recycling Batteries
Testing Batteries
Specific Battery Issues
The Memory Effect
Cordless Phone Batteries
Glossary of Battery Terms
Technical Information
Battery Comparison Chart
Primary Batteries
Carbon Zinc
Zinc Chloride
Alkaline Batteries
Standard Alkalines
Premium Alkalines
Lithium Manganese
Zinc Air
Silver Oxide
Mercuric Oxide
Secondary Batteries
Nickel Cadmium
Nickel Metal-Hydride
Lithium Ion
Lithium Ion Polymer
Lead Acid

RadioShack's On-line Battery Guidebook

Testing Batteries

The most important thing to understand about testing batteries is that batteries will not show their correct voltage unless they are under a load. If you simply take a multimeter and connect the leads to each battery terminal, you will not get an accurate reading.

Battery testers are designed to place the battery under a load in order to get an accurate reading and are best for normal consumer use; however, multimeters provide a more accurate reading of the voltage potential. If you are needing a high level of accuracy (such as for design or testing), then you should use a multimeter. If you are just wanting a device to let you plug in a battery and know whether or not it's still good, a battery tester is a better choice.

Multimeter Battery TestWhen testing batteries with a multimeter, you must have the meter set to measure DC voltage and place the battery under load by using a resistor in parallel with the test leads of the meter (see illustration at right). If the voltage reads the same on a multimeter with the resistor or without, then the battery is either low or dead and should be replaced.

A battery can be used until it is down to about 30% capacity. After that, it typically will not supply enough voltage to power the product it is being used in. The actual cut-off voltage will vary with the battery type.


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