Komatsu 830E-AC Shop Manual page 259

PROBLEM
4. The regulator has four different voltage settings
from 27.0V to 29.5V on the 28.0V systems.
Which is used?
Refer to the Regulator Removal procedure in the
Alternator Disassembly section for additional infor-
mation.
D10003 07/06
The voltage regulator is equipped with a selectable voltage
set point. This feature allows the choice of the regulated volt-
age output of the alternator according to the type of batteries
in use on the truck.
The lower voltage settings are used for maintenance-type
batteries. The maintenance-type batteries require slightly
lower charge voltage to maintain performance. Excessive
voltage settings on the maintenance-type batteries will lead to
overcharging and premature failure of the batteries.
The higher voltage settings are used for maintenance-free
batteries. In general, a vehicle equipped with maintenance-
free batteries must have the regulator charge voltage set
point adjusted to one of the two higher settings on the regula-
tor. If the voltage setting is set too low for the maintenance-
free batteries, the insufficient charge voltage will keep the
battery from reaching full charge. Over time, this can lead to a
no start condition and reduce the battery life. An incorrectly
adjusted regulator voltage set point will result in either a con-
tinuous overcharging or undercharging condition, which can
affect battery performance and shorten the battery life.
The highest regulator voltage setting can be used only on
vehicles equipped with battery isolators. The battery isolators
are generally used on vehicles with two or more batteries.
The isolator set-up allows for independent discharge of one
battery, while the other battery remains fully charged for
engine restart. Due to the design nature of the isolator, the
alternator voltage setting must be increased to overcome a
voltage drop that occurs as the current flows through the iso-
lator. This voltage drop can be as high as one Volt. If the volt-
age is set lower than the battery type requires, it will lead to
an undercharge condition, a no start situation, and will reduce
the battery life.
If regulator replacement is necessary, set the new regulator
charge voltage set point to the same voltage setting as on the
regulator being replaced. Confirm that this is the correct set-
ting for the type of battery being used. The ambient tempera-
ture may also play a role in determining the correct regulator
charge voltage set point. When the vehicle is operated contin-
uously in cold climates, and the battery is not maintaining a
state of full charge, the regulator voltage set point may be
adjusted to the next higher set point appropriate for the given
battery type.
Battery Charging Alternator
CAUSE/SOLUTION
D10-29