STARTING & CHARGING SYSTEM DIAGNOSIS

Battery

Starter

Alternator

Test Equipment

VAT–40 & AVR Voltmeter Ammeter Carbon-pile variable

resistor

Safety Issues

Batteries can explode if sparks occur around them.

Battery acid is very corrosive. It can burn skin and cause blindness.

Remove negative battery cable if making any large repairs.

Battery Identification

Conventional Lead Acid (Cap Battery or Deep Cycle)

Maintenance Free AGM (Absorbed Glass Mat)

Battery Testing

Battery capacity or load test. Battery drain test. Hydrometer test. (Cap batteries only) Special Testing for AGM Batteries (Absorbed

Glass Mat)

Battery Load Test

Discharge battery ½ cold cranking amps.

+ -

Carbon pile

voltmeterammeter

>9.6v½ CCATurn resistorto get amperage(artificial load)

Battery

On the Car Connections

Battery Services

Clean battery case Clean battery terminals Check proper hold down Charging batteries Jump starting Replacing batteries

Cleaning Batteries

Battery Charging

Standard Slow Charger2 – 12 amp capacity.

Fleet Battery Chargerhigh amps can jump andfast charge.

Jumping or Boosting aDead Battery

Positive to Positive Negative to Ground

Starting System Testing

Starter load or draw test. Starter voltage drop. Cable voltage drop. Solenoid voltage drop.

Starter Draw Test

ammeter

voltmeter

Note: ammeter in series and voltmeter in parallel.

Measure whilecranking engine

On the car connections

Battery Cable Test (Voltage drop)

voltmeter

voltmeter

Note: Voltmeters to be set at low volt scale.

0.2v max.

0.5v max.

Measure whilecranking engine

Testing the Solenoid (voltage drop)

voltmeter

0.2v max.

Measure whilecranking engine.

Starter Bench Test

Installing a New Starter

Safety tip: Always remove negative battery terminal.

Alternator/Regulator Testing

Alternator output test. Voltage regulator setting. Full field test.

Alternator Output (amps)

- +

Alternator

To vehicle load

Carbon pile

amps

Battery

Adjust to max.alternator output(artificial load)

Amp ratingon alternator

Read outputhere.

Run engine at 1500 –2000 rpm.

On the Car Connections

Voltage Regulator Setting

- +

Alternator

To vehicle load

Carbon pile

Battery

Quickly load alternatorand back off.

Run engine at 1500 –2000 rpm.

Voltmeter

13.8 - 15.3v

Full Field an Alternator

When you have a dead charging system use this test todetermine if the alternator is at fault or the regulatoris at fault.The test basically puts full battery voltage to the fieldwinding in the rotor of the alternator. If the alternator is OK it will put out maximum output and the regulatoris the problem. If no output is still noticed the alternatoris faulty.

Full Fielding

This will build a largemagnetic field in thefield coil.

Diode Scope Pattern