Activity Industry Sector

Activity Originally Created By: MaryRose Lovgren

Opener: Importance of good battery testing

Part of Lesson Plan: **Perform a battery, starter, charging system test using the VAT-40 (updated) by Eli Jaramillo

Activity Overview / Details

Materials needed:

  • Whiteboard:  Write the following:  "Load-testing the battery, starter, alternator using one machine"
  • One fully-charged battery
  • One low battery
  • One VAT-type load tester (we'll use the SUN VAT- for this lesson)


This will be a short introductory session in which students are shown how a typical load tester works.  Then they see first-hand the results from testing a good battery, and results from a low battery.


Instructor:  In the classroom:  Start the session out with a discussion about the following:

  • Being stranded by a low battery
  • Misdiagnosis of a defective alternator vs. a low battery
  • Misdiagnosis of defective starter vs. a low battery

This discussion usually sparks counter-discussions by students with similar experiences.  Limit sharing personal experience to four or five students, it could go on for a long time.

Then move into the demonstration of the VAT.  NOTE:  This is the opener for your lesson, you won't be showing specific setting up and hookups, etc.  That's in the next part.  This opener is a quick show-and-tell to emphasize the importance of testing the battery.

1)  Start by comparing the test you're doing to what repair technicians and parts counter persons do all the time.

2)  Test the good battery, show the pass voltage.  Test the low battery, show the fail voltage.

3)  Emphasize the following:

  • Importance of good understanding of this process to prevent mis-diagnosis and low customer satisfaction.
  • Safety aspects of this task including safety glasses, washed hands (battery acid).
  • Safety aspects pertaining to using this equipment:  LOAD knob always counter-clockwise unless testing, don't hold LOAD condition too long.