Lull 944E-42 Service Manual - Manual (Page 683)

9.173 Model 644E-42/944E-42 Rev. 6/04
Electrical System
d. Battery Charging
Charge rates between 3 and 50 amperes are generally
satisfactory as long as spewing of electrolyte does not
occur, or the battery does not feel excessively hot (over
125° F [52° C]). Battery temperature can be estimated by
touching or feeling the battery case. If spewing of
electrolyte occurs or temperature exceeds 125° F
(52° C), commonly referred to as “boiling” the battery, the
charging rate must be reduced or temporarily halted to
permit cooling. Failure to do so will destroy the battery.
When charging a battery, keep this point in mind:
• 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 result in a
50-ampere hour charge to the battery.
The time required for a charge will vary due to the
following conditions:
• Size of battery: For example, a completely
discharged, large, heavy-duty battery requires more
than twice the recharging as a completely
discharged small passenger car battery.
• Temperature: For example, more time will be
required to charge a battery at 0° F than at 80° F.
When a fast charger is connected to a cold battery,
the current accepted by the battery will be very low
at first, then, in time, the battery will accept a higher
rate as the battery warms.
• State of Charge: A completely discharged battery
requires more than twice as much charge as a half-
charged battery. Because the electrolyte is nearly
pure water and therefore a poor conductor in a
completely discharged battery, the current accepted
is very low at first. Later, as the charging current
causes the electrolyte acid content to increase, the
charging current will likewise increase.
• Charger Capacity: A charger that can only supply 5
amperes will require a much longer period of
charging than a charger that can supply 30 amperes
or more.
e. Battery Troubleshooting
If a battery has tested satisfactorily but then fails to
perform satisfactorily for no apparent reason, the
following items are among the more popular factors that
may help understand the cause:
1. Vehicle accessories left on, causing battery
discharge.
2. Charging system defect, such as slipping fan belt,
high wiring resistance, or faulty alternator.
3. A vehicle electrical load exceeds alternator output
capacity (common with the addition of electrical
accessories such as radio equipment, lights, air
conditioning, or window defogging/de-misting
devices).
4. Electrical system defects, such as shorted wires.
5. Extended slow speed driving with many accessories
on, and excessive engine idling (both cases DO
NOT allow engine rpm to reach a sufficient speed to
enable alternator output to sufficiently charge the
battery).
6. Loose or poor battery cable-to-post connections,
previous improper charging of a run-down battery, or
loose battery hold-down hardware.
7. High resistance connections or defects in the
starting system.
8. Failure to disconnect the battery before long periods
of vehicle storage. Small current drains of vehicle
accessories that are connected all the time can also
discharge the battery in a six- to eight-week period.
A battery left in a discharged condition for a
prolonged period of time is subject to freezing and
can become difficult to recharge.