How to Get a Reliable Result with a Car Battery Load Tester » 35-50113

1. Bring the Battery to Ambient Temperature

Measurements taken at temperatures below 0 °C will give a false result. Allow the battery to warm to room temperature indoors for 2 hours.

Good to know

A car battery generally lasts from 5–7 years unless it is defective.

There are several types of automotive batteries that vary in design: lead-acid, AGM, wet, gel, etc.

Check your battery type on the battery label.

2. Connect the Tester to the Terminals and read the voltage

Compare the voltage to the chart in the tester’s instruction manual to see if it is sufficient to perform the load test.


Between 12.3 & 12.5 v

Go to step 3
The battery is sufficiently charged

12.2 v or less

The battery is insufficiently charged

A: Charge the battery with a smart charger.

B: Remove the surface charge* by activating the windshield wipers or turning on the headlights for 20 seconds.

* This is a residual overcharge in lead-acid batteries that can give a false voltage reading above the real voltage.

3. Do the Load Test

Follow the instructions on the tester. Compare the test result to the chart in the battery’s instructions manual to know if the vehicle battery is in good condition or needs to be replaced. You can also find a chart online, but make sure it is for the same type of battery as the one in your vehicle.