1

VAT: Volt Ampere Tester

2

Battery Testing

3

Battery Testing

Basics:

Load test: At the end of 15 seconds, the battery voltage should be at least _____ volts or higher.

4

Pre-checks/set-up:

• Turn off all switches, lights, accessories, make sure all doors are _________.

• Perform a battery _______ inspection. Check for cracks, corrosion, and other damage.

• Test battery ‘open circuit’ (no load) voltage.

If less than ______ volts, charge the battery.• Remove the battery ________ cable.

5

Battery Testing

Tester set-up:

• Turn the tester large LOAD control knob fully ________ -- __________.

• Set TEST SELECTOR to the _______________ position.

• Turn voltage selector switch to _____ V.

• Use the Zero-Adjust control to adjust the AMPERES (ammeter) to read _______.

• Connect the large alligator clamp tester leads, red to battery ________, black to ___________.

• Clamp the green inductive ammeter pickup around the _________ tester lead.

6

Battery Testing

Determine test load using battery CCA

method. ( ______ ________ ____ ):

• Look up the CCA rating on the side of the battery.

• Divide that number by ___. Using this method, the load required for this test will be ______ amps.

7

Battery Testing

Determine test load using battery Amp-hour rating method:

• Look up the Amp-hour rating on the side of the battery.

• Multiply that number by ___. Using this method, the load required for this test will be ______ amps.

8

Battery Testing

• Perform battery test:• Turn the large LOAD control knob slowly _________

until the ammeter needle reaches the capacity test load you determined in your calculation.

• At the end of 15 seconds, the VOLTS needle should remain above ______ volts.

NOTE: For every 10 degrees below 70 degrees, the voltage may be 0.1 volts less than 9.6 volts.

9

Starter Testing

10

Starter Testing

• Turn off all switches, lights, accessories; make sure all ________ are closed.

• Make sure the battery is in good condition. Perform a visual inspection. Check for cracks, corrosion, other damage.

• Test battery ‘open circuit’ voltage. If less than

______ volts, charge the battery.• Disable the vehicle ignition system. If in doubt, refer

to the vehicle _______ diagram for the correct ignition system wire(s) to disconnect.

11

Starter Testing

• Turn the large LOAD control knob fully counter-clockwise.

• Set TEST SELECTOR to the____ ___________ ___________ setting.

• Turn voltage selector switch to ____ V.• Use the Zero-Adjust control to adjust the AMPERES

ammeter to read ________.• Connect the large alligator clamp tester leads, red to

battery positive post, black to negative post.• Clamp the green inductive ammeter pickup around the

negative _________ battery cable

12

Starter Testing

• Crank the engine over for about 5 seconds.

• Read the ammeter. The amperage draw should be approximately the following:

• V-8 about ______ amps.

• Six cylinder about ______ amps.

• Four cylinder about ______ amps.

13

Alternator Testing

14

Alternator Testing

Task overview:• With the engine running at about 2,000 RPM, you’ll

be applying an AMPS load on the alternator to obtain the highest AMPS reading possible without causing the battery voltage to drop lower than ____ volts.

• A low amperage output reading could mean the alternator or regulator may need replacing.

• For this test, you’ll use a VAT (____ -- _____

________ ) machine.

15

Alternator Testing

• Turn off all switches, lights, accessories, make sure all doors are closed.

• Perform a visual inspection on the battery and cable connections.

• Check for cracks, corrosion, other damage to the battery.

• Write down the alternator _______ rating specification for the vehicle you’re working on: . Use the vehicle service manual for reference.

16

Alternator Testing

• Turn the tester large LOAD control knob fully counter-clockwise.

• Turn TEST SELECTOR to #___ ____________.

• Turn VOLT selector switch to _____ ____.

• Turn TEST SELECTOR to #____ __________.

• Use the Zero-Adjust control to adjust the AMPERES (ammeter) to read ZERO.

• Connect the large alligator clamp tester leads, red to battery positive, black to negative.

• Clamp the green inductive ammeter pickup around the negative vehicle battery cable.

17

Alternator Testing

• Turn the ignition switch to ON, don’t start the vehicle.

• Read the amount of discharge on the ammeter. This reading is the vehicle ‘running amps’, or the current the alternator must supply to the vehicle before charging the battery.

• The reading is usually around 6 amps.

18

Alternator Testing

• With the engine running at around 2,000 RPM, turn the large LOAD control knob slowly clockwise to obtain the highest ammeter reading without causing the voltage to drop lower than 12 volts.

• Write down this reading: _______ Now add the running amps you figured earlier.

• Write down your final reading: _______ This reading should be within 10% of the alternator’s rated output.