PS 564
Watch voltmeter
ou, as a vehicle or equipment op-
erator, may look at your preventive
maintenance responsibilities for
lead-acid batteries as a low priority.
After all, you can’t do any more
than eyeball the batteries, cables,
connections and battery box.
But don’t forget it’s your eyes that
see things first when it comes to
battery PM. If you don’t look and
report what you see, you’ve got no
one to blame if those batteries let
you down.
In addition to what your operator
TM requires for PMCS, here’s what
you must do to get the most out of
your equipment batteries:
Most vehicles have either a volt-
meter or a BAT-GEN indicator. By
watching this gauge, you can get a
good picture of the shape the batter-
ies are in. The gauge tips you off to
trouble, so you can tip off your me-
chanic that the batteries need help.
Lead-Acid Batteries . . .
Watch Color Coding
Watch the gauge when you turn the
switch ON and before you crank up
the engine. The gauge needle should
hang in the yellow section, or between
22–26 volts. If the needle goes into the
red at the left of the gauge, your bat-
teries are weak, defective, need charg-
ing or there’s a short in the system.
Yellow: 22–26 volts
Charge is OK to start engine
Green: 26–30 volts
Before you check the gauge, turn
off all electrical components. Then,
it’s just the battery and your alter-
nator/generator showing up on the
gauge.
8
PS 564
9
Now, crank
up the engine. If the needle hangs to
the left after you’ve started the engine,
one battery could have a bad cell.
After the engine starts, run it at
fast idle—about 1,500 rpm. The bat-
tery charging system’s working OK
if the needle settles at about 28.5
volts, shown by the notch in the green
section.
Correct charging at about 28.5 volts
didn't
you check
your
voltage
indicator
before we
left?
i think
the battery's
dead!
JUST
ASK HIM IF
HE HAS A
slave
CABLE
.