Chevrolet 30 Series 1967 Service Manual page 352

ENGINE-ELECTRICAL 6Y-4
in all cells. Thus when the Indicator shows water is
needed, check the level in all six cells.
An alternate method of checking the electrolyte level
is to remove the vent plug and visually observe the
electrolyte level in the vent well. The bottom of the
vent well features a split vent which will cause the
surface of the electrolyte to appear distorted when it
makes contact. The electrolyte level is correct when
the distortion first appears at the bottom of the split
vent (fig. 4b).
ELECTROLYTE LEVEL
The electrolyte level in the Battery should be checked
regularly. In hot weather, particularly during trip driv­
ing, checking should be more frequent because of more
rapid loss of water. If the electrolyte level is found to
be low, then colorless, odorless, drinking water should
be added to each cell until the liquid level rises to the
split vent located in the bottom of the vent well. DO NOT
OVERFILL because this will cause loss of electrolyte
resulting in poor performance, short life, and excessive
corrosion.
CAUTION:
During service only water should
be added to the Battery, not electrolyte.
V
The liquid level in the cells should never be allowed to
drop below the top of the plates, as the portion of the
plates exposed to air may be permanently damaged with
a resulting loss in performance.
WATER USAGE
Excessive usage of water indicates the Battery is
being overcharged. The most common causes of over­
charge are high Battery operating temperatures, too
high a voltage regulator setting or poor regulator ground
wire connection. Normal Battery water usage is ap­
proximately one to two ounces per month per battery.
CLEANING
The external condition of the Battery should be checked
periodically for damage or for the presence of dirt
and corrosion. The top of the Battery should be kept
clean. An accumulation of acid film and dirt may permit
current to flow between the terminals, which will slowly
discharge the Battery. For best results when cleaning
the top of B atteries, wash first with a diluted ammonia
or a soda solution to neutralize any acid present, then
flush with clean water. Care must be taken to keep vent
plugs tight, so that the neutralizing solution does not
enter the cells.
CABLES
To insure good electrical contact, the cables should
be clean and tight on the battery posts. If the posts
o r cable terminals are corroded, the cables should be
disconnected and the terminals and clamps cleaned sepa­
rately with a soda solution and a wire brush. After
cleaning and installing clamps, apply a thin coating of
petroleum jelly on the cable clamps to retard corrosion.
CARRIER AND HOLD-DOWN
The Battery ca rrie r and hold-down should be clean
and free from corrosion before installing the Battery.
The carrie r should be in a sound mechanical condition
so that it will support the Battery securely and keep it
level.
To prevent the Battery from shaking in its ca rrier,
the hold-down bolts should be tight (50-80 in. lbs.).
However, the bolts should not be tightened to the point
where the Battery case or cover will be placed under a
severe strain.
BATTERY SAFETY PRECAUTIONS
When Batteries are being charged, an explosive gas
mixture forms in each cell.
through the holes in the vent plugs and may form an
explosive atmosphere around the Battery itself if venti­
lation 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.
The following precautions should be observed to pre­
vent an explosion:
1. Do not smoke near Batteries being charged or
which have been very recently charged.
2. Do not break live circuits at the terminals of Bat­
teries 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 fast chargers. Poor con­
nections are a common cause of electrical arcs
which cause explosions.
BATTERY CHARGING
There are three methods of recharging Batteries.
They differ basically in the length of time the Battery
is charged and the rate at which charging current is
supplied. One is the Slow Charge method, the second is
the Fast Charge method, and the third is the Emergency
Boost Charge method.
Before recharging a Battery by any method, the elec­
trolyte level must be checked and adjusted if necessary.
SLOW CHARGING
The Slow Charge method supplies the Battery with a
relatively low current flow for a relatively long period
of time. This is the only method that will bring the Bat­
tery to a full state of charge.
The Slow Charge method consists of charging at ap­
proximately a 4 ampere rate for 24 hours or more if
necessary to bring the Battery to full charge. A fully
charged condition is reached when the cells are gassing
freely and three corrected specific gravity readings
taken at hourly intervals show no increase.
FAST CHARGING
The Fast Charge method supplies current to the Bat­
tery at a 40 to 50 ampere rate for a 1 1/2 hour period
of time. If the electrolyte temperature reaches 125°F.
before the 1 1/2 hour period is completed, the Battery
must be taken off charge temporarily, or the charging
rate reduced to avoid damage to the Battery.
Although a Battery cannot be brought to a fully charged
condition during Fast Charge, it can be substantially
recharged or ''boosted" . In order to bring the Battery
to a fully charged condition, the charging cycle must be
finished by the Slow Charge method.
Part of this gas escapes
CHEVROLET TRUCK SERVICE M ANUAL