fall below 7.2 volts during or after the thirty second
discharge period. The CCA required is generally
higher as engine displacement increases, depending
also upon the starter current draw requirements.
• Reserve Capacity - The Reserve Capacity (RC)
rating specifies the time (in minutes) it takes for bat-
tery terminal voltage to fall below 10.5 volts, at a
discharge rate of 25 amperes. RC is determined with
the battery fully-charged at 26.7° C (80° F). This rat-
ing estimates how long the battery might last after a
charging system failure, under minimum electrical
load.
• Ampere-Hours - The Ampere-Hours (AH) rat-
ing specifies the current (in amperes) that a battery
can deliver steadily for twenty hours, with the volt-
age in the battery not falling below 10.5 volts. This
rating is also sometimes identified as the twenty-
hour discharge rating.
SPECIAL TOOLS
BATTERY SPECIAL TOOLS
BATTERY
DESCRIPTION
From the factory, this model is equipped with a
maintenance-free battery. The battery is located in
the trunk. (Fig. 2).
Maintenance-free
batteries
have
non-removable
battery vent caps. Water cannot be added to this bat-
tery. Under normal service the composition of this
battery reduces gassing and water loss at normal
charge rates. If the battery electrolyte level becomes
low, this battery must be replaced.
OPERATION
The battery is designed to store electrical energy in
a chemical form. When an electrical load is applied to
the terminals of the battery, an electrochemical reac-
tion occurs. This reaction causes the battery to dis-
charge electrical current from its terminals. As the
battery discharges, a gradual chemical change takes
place within each cell. The sulfuric acid in the elec-
trolyte combines with the plate materials, causing
both plates to slowly change to lead sulfate. At the
same time, oxygen from the positive plate material
combines with hydrogen from the sulfuric acid, caus-
ing the electrolyte to become mainly water. The
chemical changes within the battery are caused by
the movement of excess or free electrons between the
positive and negative plate groups. This movement of
electrons
produces
a
flow
of
electrical
current
through the load device attached to the battery ter-
minals.
As the plate materials become more similar chem-
ically, and the electrolyte becomes less acid, the volt-
age potential of each cell is reduced. However, by
charging the battery with a voltage higher than that
of the battery itself, the battery discharging process
is reversed. Charging the battery gradually changes
the sulfated lead plates back into sponge lead and
MICRO 420 BATTERY TESTER
Fig. 2 BATTERY LOCATION
1 - BATTERY COVER
2 - BATTERY
3 - HOLDDOWN BRACKET
8F - 6
BATTERY SYSTEM
ZB
BATTERY SYSTEM (Continued)