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ELECTRICAL SYSTEM DESCRIPTION
The truck utilizes a 24VDC electrical system which
supplies power for all non-propulsion electrical com-
ponents. The 24VDC is supplied by four 12 volt stor-
age batteries wired in series and parallel. The
batteries are a lead-acid type, each containing six 2-
volt cells. With keyswitch "On", and engine not oper-
ating, power is supplied by batteries. When the
engine is operating, electrical power is supplied by a
24 volt alternator.
BATTERY
During operation, the storage batteries function as an
electrochemical device for converting chemical
energy into the electrical energy required for operat-
ing the accessories when the engine is shut down.
Lead-acid storage batteries contain sulfuric acid,
which if handled improperly may cause serious
burns on skin or other serious injuries to person-
nel. Wear protective gloves, aprons and eye pro-
tection when handling and servicing lead-acid
storage batteries. See the precautions in Section
"A" of this manual to insure proper handling of
batteries and accidents involving sulfuric acid.
Maintenance and Service
The electrolyte level of each cell should be checked
at the interval specified in the Lubrication and Ser-
vice Section "P", and water added if necessary. The
proper level to maintain is 3/8 - 1/2 in. (10-13 mm)
above the plates. To insure maximum battery life, use
only distilled water or water recommended by the
battery manufacturer. After adding water in freezing
weather, operate the engine for at least 30 minutes to
thoroughly mix the electrolyte.
DO NOT SMOKE or allow flame around a dead
battery or during the recharging operation. The
expelled gas from a dead cell is extremely explo-
sive.
D02023
24VDC ELECTRIC SUPPLY SYSTEM
24 VDC Electric Supply System
Excessive consumption of water indicates leakage or
overcharging. Normal water usage for a unit operat-
ing eight hours per day is about one to two ounces
per cell per month. For heavy duty operation (24
hour) normal consumption should run about one to
two ounces per cell per week. Any appreciable
increase over these figures should be considered a
danger signal.
Troubleshooting
Two most common troubles that occur in the charg-
ing system are undercharging and overcharging of
the truck's batteries.
An undercharged battery is incapable of providing
sufficient power to the truck's electrical system.
Some possible causes for an undercharged battery
are:
• Sulfated battery plates
• Loose battery connections
• Defective wire in electrical system
• Loose alternator drive belt
• A defective alternator
• A defective battery equalizer
Overcharging, which causes battery overheating, is
first indicated by excessive use of water. If allowed to
continue, cell covers will push up at the positive ends
and in extreme cases the battery container will
become distorted and cracked.
Leakage can be detected by continual wetness of the
battery or excessive corrosion of the terminals, bat-
tery carrier and surrounding area. (A slight amount of
corrosion is normal in lead-acid batteries). Inspect
the case, covers and sealing compound for holes,
cracks or other signs of leakage. Check battery hold
down connections to make sure the tension is not
great enough to crack the battery, or loose enough to
allow vibration to open the seams. A leaking battery
should be replaced.
To remove corrosion, clean the battery with a solution
of ordinary baking soda and a stiff, non-wire brush
and flush with clean water. Make sure none of the
soda solution is allowed into the battery cells. Be
sure terminals are clean and tight. Clean terminals
are very important in a voltage regulated system.
Corrosion creates resistance in the charging circuit
which causes undercharging and gradual starvation
of the battery.
D2-1
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Troubleshooting
