A battery tester is an inexpensive alternative to a multimeter for testing the battery and charging system. It can tell you if the alternator is not charging the battery or if the battery is failing, and it can read measurements like volts (V), state of health (SoH), state of charge (SoC), cranking amps (CA), and more. This post reviews how to use a battery tester to test the battery and the charging system yourself.
How to Use a Battery Tester in 14 Steps
A battery tester works on conductance. It will send a flow of alternating current (AC) through the battery and measure the return signal.
The battery tester has two leads—one for the positive battery terminal and one for the negative battery terminal, and it does not have a power button but turns on once it’s connected.
Steps for Using a Battery Tester
- Connect the Positive (red) Lead to the Positive Battery Terminal
Clamp the positive or red lead to the positive battery terminal
- Connect the Negative (black) Lead to the Negative Battery Terminal
Clamp the negative or black lead to the negative battery terminal
- Read the Battery Voltage
The battery tester should report the battery voltage.
In this example, the battery voltage reads at 11.9 volts, which is low. Batteries should typically read between 12.4 and 12.8 volts
- Press Enter to Put in Info and Access More
Push the enter button to enter info about the battery and access different tests and readings
- Press enter for REGULAR LIQUID under BATTERY TYPE
Press enter for REGULAR LIQUID under BATTERY TYPE, which means the tool is asking for the battery type. For a typical car battery, this setting will be “REGULAR LIQUID”
Learn more about car batteries and how to test them for battery health
- Select CA under RATING STANDARD
Select the rating standard for your battery, which in the US is usually cranking amps (CA)
- Input the CA number on the Battery and Press Enter
Adjust the RATING CAPACITY number to reflect the cranking amp (CA) number on the battery, which is not to be confused with cold cranking amps (CCA). Then press Enter
- Read the Battery Analyzer’s Battery Health Report
The battery analyzer will test the battery and will report GOOD RECHARGE with the battery’s CA if the battery is good and needs to be recharged.
Press the arrow to see state of health (SoH) and state of charge (SoC) measurements, which measure a battery health and charge levels on a 100-point percentage scale
- Press Enter and Select between a Battery Charge Test or a System Charge Test
Push enter to select between a battery charge test and a system charge test
- Press the Next Arrow to Select the System Charge Test
Select the system charge test by pressing the next arrow
- Press Enter, Shut off all Electrical Loads, and Start the Vehicle
Press enter to start the test. You have 1 minute to start the vehicle. The tool will remind you to shut off all “loads” such as the headlights and radio
- Read the Cranking Volts
The analyzer will read the cranking volts and report if the reading is normal
- Push Enter and Read the Idle Volts
Press enter to access the charging test and press enter when commanded. The tool will remind you to shut off all “loads” such as the headlights and radio
The analyzer will read the idle volts and report if the reading is normal, which means there is normal charging and that the alternator is working
- Press Enter, Turn on Electrical Loads, and Press Enter to Read the Load Volts
Press enter. The tool will command remind you to turn on “loads” such as the headlights and radio. Press enter.
The analyzer will read the load volts, which will tell you if the alternator is able to keep up with the load and keep the battery charged, and tell you if the reading is normal.
Since we know the charging system is working and the battery is good and just needs to be recharged, we can drive the vehicle to recharge it or recharge it with a portable charger.
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Learn how to diagnose and fix parts on your own car with 1A Auto’s how-to videos that have step-by-step instructions from real mechanics for many makes and models.
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