Opel 1900 1973 Service Manual page 28

421 Test F$ocedure
1. Visual Inspection - The first step in testing the
Energizer br 12-V& Battery should be a visual in-
spection which very often will save time, labor and
expense in determining the condition.
(a) Check for broken or cracked case or cover.
(d) Check for other visible signs of physical damage.
Obvious d?mage as a result of conditions described
above indicates the need for Energizer or battery
2. The "421" Test is a programmed test procedure
consisting bf a series of timed discharge and charge
events, reqtdring approximately 2 to 3 minutes, that
will determine the condition of the Energizer or bat-
tery with a high degree of accuracy when used in
Testers a$ produced by a number of different manu-
facturers r+nd their directions for tester operation
should be carefully followed. General comments on
overall "42 1" Tester operation follow:
(a) Energi@rs or batteries
to making this test.
prior
be hidden by the charging and erroneous test results
will be obtpined.
(b) Erratic, or extremely low, initial meter readings
may indicate poor connections at the tester termi-
nals.
forming the 421 Test.
(c) All meter readings should be made
after the meter indicator light comes on even if the
meter needle is still moving.
(d) If additional discharges are required after the
initial discbarge, set meter indicator following the
discharge cycle.
be replaced.
complaint or indication of poor performance, should
be left in s+vice. Posts, cable clamps, and top should
be cleaned, water should be added and recharging
should be ,performed, if required. For dependable
and reliable battery service, the battery should be in
at least a 75 per cent state-of-charge.
of being questionable because of owner complaint, or
should nor be charged
Defects within the unit can
immediately
BATTERY AND CABLES - ALL MODELS
age of the battery, should be further tested by the
Hydrometer Test.
HYDROMETER TEST OF BATTERY
The 421 Battery Test as described in the previous
paragraph is the fastest and most accurate means of
determining the serviceability of a one-piece cover
battery. However, ifa 421 Battery Tester is not avail-
able, a hydrometer test may be used on a battery that
has failed to give proper service.
Hydrometer Test
1. Fully charge battery.
2. Measure specific gravity of each cell as described
in sub-paragraph below.
Decide battery serviceability as follows:
(a) If all cells read between 1.230 and 1.310, the
is okay. All it needed was a full charge.
battery
(b) After fully charging battery, if any cell reads less
than 1.230, the battery is defective and should be
replaced.
Use of Hydrometer
The Hydrometer measures the percentage of sulphu-
ric acid in the battery electrolyte in terms of specific
gravity. As a battery drops from a charged to a dis-
charged condition, the acid leaves the solution and
enters the plates, causing a decrease in specific
gravity of electrolyte. With a hydrometer, an indica-
tion of the concentration of the electrolyte is ob-
tained.
The specific gravity of the electrolyte varies not only
with the percentage of acid in the liquid, it also varies
with temperature. As temperature increases, the
electrolyte expands so that the specific gravity is re-
duced. As temperature drops, the electrolyte con-
tracts so that the specific gravity
these variations in specific gravity are taken into
account, the specific gravity obtained by the hy-
drometer may not give a true indication of the con-
centration of acid in the electrolyte.
Correction can be made for temperature
the hydrometer reading for every 10 degrees F. that
the electrolyte is above 80 degrees F. or subtracting
80 degrees F. Figure IA-4 shows the exact correction
degrees F., the three steps used in obtaining the cor-
rected or true specific gravity, and two examples
showing how it is figured.
increases. Unless
by adding