Agm Battery Rating; Battery Testing; Visual Inspection; Removing Surface Charge - PREVOST H3-41 Maintenance Manual

9.7

AGM BATTERY RATING

Each of the 12-volt batteries used on the vehicle
has the following rating:
Reserve capacity: 200 minutes
•
Cold Cranking Amps (CCA): 800 @ 0
•
(-18 C)
o
• Weight: 69 lb (26,7 kg)
The reserve capacity is defined as the number
of minutes a new, fully charged battery at 80
(26,6 C) can be discharged at 25 amperes and
o
maintain a minimum of 1.75 volts per cell (10.5
volts total for one 12-volt battery). This rating
can be used as a basis for determining how long
a vehicle might run after an alternator failure.
The cold cranking rating is defined as the
minimum discharge current a battery will deliver
in amperes for 30 seconds at 0
maintaining a minimum of 1.2 volts per cell (7.2
volts total for one 12-volt battery). This rating
can be used as a basis for comparing starting
performance.
9.8

BATTERY TESTING

Several factors influence battery performance.
The methods and
proposed here will ensure your batteries are in
good shape.
9.8.1

Visual Inspection

1. Check the outside of the battery for a broken
or cracked cover or case that could permit
loss of electrolyte. If obvious physical
damage is noted, replace the battery. If the
battery is bulged, replace the battery. Also
check for wet areas around the terminals.
2. Check for loose terminal posts, cable
connections, damaged cables, and for
evidence of corrosion. Correct conditions as
required before proceeding with tests.
3. Check for damaged or loose battery tie-
downs.
9.8.2

Removing Surface Charge

Disconnect cables from the battery and attach
alligator clamps to the contact lead pad on the
battery as shown in Figure 56. Connect a load
F
o
F
o
F (-18 C) while
o o
inspection procedures
PA1621 Maintenance Manual All Series | Revised Sept 2019
SECTION 06: ELECTRICAL
equal to half the CCA across the terminal for 5
seconds to remove surface charge from the
battery.
9.8.3

Load Test

This test is one means of checking the battery to
determine its ability to function as required in the
vehicle.
To make this test, use test equipment that will
withstand a heavy electrical load from the
battery, such as a carbon pile load tester. A
charging system analyzer test equipment may
also be used.
FIGURE 55: LOAD TEST
CAUTION
Observe the polarity of the meters and the
battery when making connections, and select
the correct meter range.
1. You cannot test a discharged battery. If the
voltage is below 12.4 volts, be sure to
completely charge
continuing.
2. Connect a voltmeter, ammeter, and a
variable load resistance as illustrated in
Figure 55.
3. Apply a load equal to one-half the CCA
rating @ 0 F for 15 seconds. Note the
o
voltage at 15 seconds with the load on and
immediately shut the load off.
4. A voltage reading at least equal to the value
from the chart below indicates a good
battery.
5. If the voltage reading is less than the value
from the chart
temperature, replace the battery.
06064
the battery before
for a given battery
65