PREVOST LE MIRAGE XLII BUS SHELLS, Maintenance Manual

Page: 130 / 1260

Section 06: ELECTRICAL
PA1564
18
3.6 BATTERY CHARGING
The batteries used on this vehicle can be
charged either on or off the vehicle; however,
when they are removed from the vehicle, it is
recommended that an adapter kit, which is
available from any "A/C DELCO" dealer, be used
in charging sealed-terminal batteries. Use the
booster terminals to charge the batteries when
they are left on vehicle and
make sure that the
ignition key switch is set to the “On”
position.
The alligator clamps of the tester or charger must
be placed between the terminal nuts and the
lead pads of the terminal studs (Fig. 17) after the
vehicle cables are detached. The alligator
clamps should make firm contact with the lead
pads.
DANGER
During charging of the batteries, an explosive
gas mixture forms in each cell. Part of this gas
escapes through the vent holes and may form
an explosive atmosphere around the battery
itself if ventilation is poor. This explosive gas
may remain in or around the battery for
several hours after it has been charged.
Sparks or flames can ignite this gas causing
an internal explosion, which may shatter the
battery.
1. Do not smoke near a battery which is
being charged or which has been recently
charged.
2. Do not break live circuits at battery
terminals because a spark usually occurs
at the point where a live circuit is broken.
Care must always be taken when
connecting or disconnecting booster leads
or cable clamps on chargers. Poor
connections are a common cause of
electric arcs, which cause explosions.
3. The electrical system on this vehicle is
negative ground. Installing the batteries
with the positive terminals grounded or
incorrect use of the booster battery and
jumper cables will result in serious
damage to the alternator, batteries and
battery cables.
NOTE
If this connection cannot be made because of
the alligator clamp design, the load value for
testing must be reduced from 290 to 260
amperes.
On rare occasions, such as those that occur
following prolonged cranking, the green dot in
the test indicator may still be visible when the
battery is obviously discharged. Should this
occur, a boost charge of 20 amperes-hour is
recommended. Under normal operating
conditions, do not charge battery if the green dot
is visible. The battery should never be charged if
the test indicator (hydrometer) is clear or light
yellow. If this occurs, replace the battery.
A charge rate between 3 and 50 amperes is
generally satisfactory for any maintenance-free
battery as long as spewing of electrolyte does
not occur or the battery does not feel excessively
hot (over 125ºF (52ºC)). If spewing or violent
gassing of electrolyte occurs or battery
temperature exceeds 125ºF (52ºC), the charging
rate must be reduced or temporarily stopped to
allow cooling and to avoid damaging the battery.
Battery temperature can be estimated by
touching or feeling the battery case. The battery
is sufficiently charged when the green dot in the
built-in hydrometer is visible. No further charging
is required. Shake or tilt the battery at hourly
intervals during charging to mix the electrolyte
and see if the green dot appears.
WARNING
Always turn off the charger before connecting
or disconnecting to a battery.
NOTE
The charge rate must be doubled when the
batteries are charged by the booster
terminals, because of the series-parallel
circuit.
Battery charging consists of a charge current in
amperes for a period of time in hours. Thus, a 25
ampere charging rate for 2 hours would be a 50
ampere-hour charge to the battery. Most
batteries, whose load test values are greater
than 200 amperes, will have the green dot visible
after at least a 75 ampere-hour charge. In the
event that the green dot does not appear,
replace the battery.