Service Manual

Workman GTX GasolinePage 5 − 28Electrical System
Battery Testing
1. If the battery design allows removal of battery caps,
conduct a hydrometer test of the battery electrolyte:
IMPORTANT: Make sure the area around the cells is
clean before opening the battery caps.
A. Measure the specific gravity of each cell with a
hydrometer. Draw electrolyte in and out of the
hydrometer barrel prior to taking a reading to warm−
up the hydrometer. At the same time take the tem-
perature of the cell.
B. Temperature correct each cell reading. For each
10F (5.5C) above 80F (27C) add 0.004 to the specif-
ic gravity reading. For each 10
o
F (5.5C) below 80F
(27C) subtract 0.004 from the specific gravity read-
ing.
Example: Cell Temperature 100F
Cell Gravity 1.245
ADD (20 above 80F) 0.008
Correction to 80F 1.253
C. If the difference between the highest and lowest
cell specific gravity is 0.050 or greater or the lowest
cell specific gravity is less than 1.225, charge the bat-
tery. Charge at the recommended rate and time giv-
en in Charging or until all cells specific gravity is
1.225 or greater with the difference in specific gravity
between the highest and lowest cell less than 0.050.
If these charging conditions can not be met, replace
the battery.
2. Perform a high−discharge battery test with an adjust-
able load tester.
This is one of the most reliable means of testing a battery
as it simulates the cold−cranking test. A commercial bat-
tery load tester is required to perform this test.
CAUTION
Follow the battery load tester manufacturer’s
instructions when using a load tester.
A. Check the voltage across the battery terminals
prior to testing the battery. If the voltage is less than
12.0 VDC, recharge the battery before load testing.
B. Make sure the battery terminals are free of corro-
sion.
C. If the battery has been charged, apply a 150 amp
load for 15 seconds to remove the surface charge.
Use a battery load tester following the manufactur-
er’s instructions.
D. If battery design allows, measure the tempera-
ture of the electrolyte in the center cell. If battery is
sealed, estimate electrolyte temperature based on
ambient temperature of surroundings.
E. Connect a battery load tester to the battery termi-
nals following the manufacturer’s instructions.
Connect a digital multimeter to the battery terminals.
F. Apply a test load of 150 amps (one half the Crank-
ing Performance) for 15 seconds.
G. Take a battery voltage reading at 15 seconds,
then remove the load. Record this test voltage read-
ing.
H. Using the table below, determine the minimum
test voltage for the cell temperature reading.
Minimum
Test Voltage
Battery Electrolyte
Temperature
9.6 70F (and up) 21.1C (and up)
9.5 60F 15.6C
9.4 50F 10.0C
9.3 40F 4.4C
9.1 30F −1.1C
8.9 20F −6.7C
8.7 10F −12.2C
8.5 0F −17.8C
I. If the test voltage is below the minimum, replace
the battery. If the test voltage is at or above the mini-
mum, return the battery to service.