Chevrolet 10 Series 1968, Service Manual, Page: 429 / 713

ENGINE-ELECTRICAL 6Y-4
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 dis­
charge the Battery. For best results when cleaning the
top of Batteries, 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
or 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 carrier and hold-down should be clean
and free from corrosion before installing the Battery.
The carrier 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 carrier,
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. Part of this gas escapes
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.
EMERGENCY BOOST CHARGING
In cases where the Battery is not sufficiently charged
to crank the engine, an emergency boost charge may be
applied as a temporary expedient in order to crank the
engine. The Emergency Boost Charge method consists
of charging at a 40 to 50 ampere rate for a period of
one-half hour.
12 VOLT BATTERY
SUGGESTED CHARGING RATES
(100 Amp*hr or Less Capacity)
Type
of Charge
Length
of Time
Charging
Rate
Boost Charge for
Light Load Test
20 Minutes
50 Amps
Slow Chage
24 Hours 4 Amps
Fast Charge 1-1/2 Hours 40-50 Amps
Emergency Quick
Boost
30 Minutes 40-50 Amps
Dry Charge
Warm-up Boost
10 Minutes 15 Amps
CHEVROLET TRUCK SERVICE MANUAL