Isuzu N-Series. Service manual - part 534

Engine Electrical   6D-3

Battery

General Description

There are six battery fluid caps at the top of the battery.

Diagnosis

Visual Inspection

Inspect the battery for obvious physical damage, such
as a cracked or broken case, which would permit
electrolyte loss.
Replace the battery if obvious physical damage is
discovered during inspection.
Check for any other physical damage and correct it as
necessary.

Fluid Level Check

The fluid level should be between the upper level line
and lower level line on side of the battery.

Legend

1. Battery
2. Upper Level
3. Lower Level

Voltage Check

1. Put voltmeter test leads to battery terminals.

a. VOLTAGE IS 12.4V OR ABOVE - Go to “Load

Test”.

b. VOLTAGE IS UNDER 12.4V - Go to procedure

2 below.

2. Determine fast charge amperage from

specification.
Fast charge battery for 30 minutes at amperage
rate no higher than specified value.
Take voltage and amperage readings after charge.
a. VOLTAGE IS ABOVE 16V AT BELOW 1/3 OF

AMPERAGE RATE - Replace battery.

b. VOLTAGE IS ABOVE 16V AT ABOVE 1/3 OF

AMPERAGE RATE - Drop charging voltage to
15V and charge for 10 — 15 hours.

Then go to “Load test”.
c. VOLTAGE IS BETWEEN 12V AND 16V 

- Continue charging at the same rate for an
additional 3-1/2 hours. Then go to “Load test”.

d. VOLTAGE IS BELOW 12V - Replace battery.

Load Test

1. Connect a voltmeter and a battery load tester

across the battery terminals.

2. Apply 300 ampere load for 15 seconds to remove

surface charge from the battery.
Remove load.

3. Wait 15 seconds to let battery recover. Then apply

specified load from specifications (See Main Data
and Specifications in this section).
Read voltage after 15 seconds, then remove load.
1) VOLTAGE DOES NOT DROP BELOW THE

MINIMUM LISTED IN FOLLOWING TABLE 
- The battery is good and should be returned to
service.

2) VOLTAGE IS LESS THAN MINIMUM LISTED

- Replace battery.

On-vehicle Service

Battery Charging

Observe the following safety precautions when charging
the battery:

1. Never attempt to charge the battery when the fluid

level is below the lower level line on the side of the
battery.
In this case, the battery must be replaced.

N6A0983E

ESTIMATED 

TEMPERATURE

MINIMUM VOLTAGE

°F

°C

70

21

9.6

60

16

9.5

50

10

9.4

40

4

9.3

30

− 1

9.1

20

− 7

8.9

10

− 12

8.7

0

− 18

8.5

The battery temperature must be estimated by feel 
and by the temperature the battery has been 
exposed to for the preceding few hours.

6D-4   Engine Electrical

2. Pay close attention to the battery during the

charging procedure.
Battery charging should be discontinued or the
rate of charge reduced if the battery feels hot to the
touch.
Battery charging should be discontinued or the
rate of charge reduced if the battery begins to gas
or spew electrolyte from the vent holes.

3. Battery temperature can have a great effect on

battery charging capacity.

4. The sealed battery used on this vehicle may be

either quick-charged or slow-charged in the same
manner as other batteries.
Whichever method you decide to use, be sure that
you completely charge the battery. Never partially
charge the battery.

Jump Starting

Jump Starting With An Auxiliary (Booster) Battery

Caution:
Never push or to the vehicle in an attempt to start it.
Serious damage to the emission system as well as
other vehicle parts will result.
Treat both the discharged battery and the booster
battery with great care when using jumper cables.
Carefully follow the jump starting procedure, being
careful at all times to avoid sparking.

WARNING:
FAILURE TO CAREFULLY FOLLOW THE JUMP
STARTING PROCEDURE COULD RESULT IN THE
FOLLOWING:

1. SERIOUS PERSONAL INJURY, PARTICULARLY

TO YOUR EYES.

2. PROPERTY DAMAGE FROM A BATTERY

EXPLOSION, BATTERY ACID, OR AN
ELECTRICAL FIRE.

3. DAMAGE TO THE ELECTRONIC COMPONENTS

OF ONE OR BOTH VEHICLES PARTICULARLY.

Never expose the battery to an open flame or electrical
spark. Gas generated by the battery may catch fire or
explode.
Remove any rings, watches, or other jewelry before
working around the battery. Protect your eyes by
wearing an approved set of goggles.
Never allow battery fluid to come in contact with your
eyes or skin.
Never allow battery fluid to come in contact with fabrics
or painted surfaces.
Battery fluid is a highly corrosive acid.
Should battery fluid come in contact with your eyes,
skin, fabric, or a painted surface, immediately and
thoroughly rinse the affected area with clean tap water.
Never allow metal tools or jumper cables to come in
contact with the positive battery terminal, or any other
metal surface of the vehicle. This will protect against a
short circuit.

Always keep batteries out of the reach of young
children.
Jump Starting Procedure

1. Set the vehicle parking brake.

If the vehicle is equipped with an automatic
transmission, place the selector lever in the
“PARK” position.
If the vehicle is equipped with a manual
transmission, place the shift lever in the
“NEUTRAL” position.
Turn “OFF” the ignition.
Turn “OFF” all lights and any other accessory
requiring electrical power.

2. Look at the built-in hydrometer. (If equipped)

If the indication area of the built-in hydrometer is
completely clear, do not try to jump start.

3. Attach the end of one jumper cable to the positive

terminal of the booster battery.
Attach the other end of the same cable to the
positive terminal of the discharged battery.
Do not allow the vehicles to touch each other.
This will cause a ground connection, effectively
neutralizing the charging procedure.
Be sure that the booster battery has a 12 volt
rating.

4. Attach one end of the remaining cable to the

negative terminal of the booster battery.
Attach the other end of the same cable to a solid
engine ground (such as the A/C compressor
bracket or the generator mounting bracket) of the
vehicle with the discharged battery.
This ground connection must be at least 450 mm
(18 in) from the battery of the vehicle whose
battery is being charged.

WARNING:
NEVER ATTACH THE END OF THE JUMPER CABLE
DIRECTLY TO THE NEGATIVE TERMINAL OF THE
DEAD BATTERY.

5. Start the engine of the vehicle with the good

battery.
Make sure that all unnecessary electrical
accessories have been turned “OFF”.

6. Start the engine of the vehicle with the dead

battery.

7. To remove the jumper cables, follow the above

directions in the reverse order.
Be sure to first disconnect the negative cable from
the vehicle with the discharged battery.

Removal

1. Negative cable
2. Positive cable
3. Retainer screw and rods
4. Retainer
5. Battery

Engine Electrical   6D-5

Installation

To install the battery, follow the removal procedure in
the reverse order, noting the following points:

1. Make sure that the rod is hooked on the body side.

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6D-6   Engine Electrical

Charging System

General Description 

The main charging system components are the
batteries, the generator and the battery discharge
indicator light circuit. The generator is a 110-amp,
selfrectifying type with a built-in regulator. The battery
discharge indicator light is mounted in the instrument
panel. For more details on this circuit, refer to “Meter
and Warning/Indicator Lights” in Section 8.

Circuit Diagram

Legend

1. Engine Control Switch
2. Generator (Integral Regulator)
3. Charge Relay
4. To Heater and A/C Relay
5. Low Charge Indicator Light
6. Glow Plug Relay
7. Glow Plugs

8. Glow Plug Indicator Light
9. ECM

10. Starter Cut Relay

11. To Exhaust Brake Solenoid Valve

12. Starter Relay
13. Starter
14. ECM Main Relay

N6A6586E