B
BATTERIES AND CHARGING
Read all of SAFETY and this section before attempting any procedure. Pay particular attention to Notices, Cautions, Warnings and Dangers.
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Repair and Service Manual
634756
The batteries must be cleaned and all deposits neutral-
ized and removed from the battery case to prevent self
discharge. The batteries should be tested or recharged at
thirty day minimum intervals.
.
Fig. 6 Freezing Point of Electrolyte
Battery Charging
The
battery charger is designed to fully charge the battery
set. If the batteries are severely deep cycled, some auto-
matic battery chargers contain an electronic module that
may not activate and the battery charger will not function.
Automatic chargers will determine the correct duration of
charge to the battery set and will shut off when the battery
set is fully charged. Always refer to the instructions of the
specific charger being used.
Before charging, the following should be observed:
Do not overfill batteries. The charging cycle will
expel electrolyte and result in component damage.
•
The electrolyte level in all cells must be at the recom-
mended level and cover the plates.
•
The charging must take place in an area that is well
ventilated and capable of removing the hydrogen gas
that is generated by the charging process. A mini-
mum of five air exchanges per hour is recom-
mended.
•
The charging connector components must be in
good condition and free from dirt or debris.
•
The charger connector must be fully inserted into the
vehicle receptacle.
•
The charger connector/cord set must be protected
from damage and located in an area to prevent injury
that may result from personnel tripping over the cord
set.
•
The charger is automatically turned off during the
connect/disconnect cycle and therefore no electrical
arc is generated at the DC plug/receptacle contacts.
In some portable chargers, there will be a rattle present
in the body of the charger DC plug. This rattle is caused
by an internal magnet contained within the charger plug.
The magnet is part of the interlock system that prevents
the vehicle from being driven when the charger plug is
inserted in the vehicle charging receptacle.
AC Voltage
Battery charger output is directly related to the input volt-
age. If vehicle is receiving an incomplete charge in a nor-
mally adequate time period, low AC voltage could be the
cause and the power supply should be checked.
FAULT DIAGNOSIS
In general, fault diagnosis will be done for two distinct
reasons:
•
A battery that performs poorly and is outside of the
manufacturers specification should be identified in
order to replace it under the terms of the manufac-
turer’s warranty. Different manufacturers have differ-
ent requirements. Consult the battery manufacturer
or the manufacturer’s representative for specific
requirements.
•
The second reason is to determine why a vehicle is
not performing adequately. A vehicle that runs slowly
or a vehicle that is unable to operate for the time
required are examples of performance problems.
A new battery must mature before it will develop its maxi-
mum capacity. Maturing may take up to 100 charge/dis-
charge cycles. After the maturing phase is complete,
battery capacity will start to diminish. The only way to
determine the capacity of a battery is to perform a load
test using a discharge machine following manufacturer’s
recommendations.
A cost effective way to identify a poorly performing battery
is to use a hydrometer to identify a battery in a set with a
lower than normal specific gravity. Once the problematic
cell or cells are are identified, the suspect battery can be
removed and replaced. At this point there is nothing that
1.100
1.120
1.160
1.200
1.240
1.280
1.140
1.180
1.220
1.260
1.300
+15
+5
-5
-15
-25
-35
-45
-55
-65
-75
-85
-95
-9
-15
-21
-26
-32
-37
-43
-48
-54
-60
-65
-71
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SPECIFIC GRAVITY
ELECTROLYTE FREEZING POINT
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