Service Manual

Workman HD Series Page 8 -- 31 Electrical System
Battery Testing
1. If battery filler caps are removable, conduct a
hydrometer test of the battery electrolyte.
IMPORTANT: Make sure the a rea 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--
upthehydrometer. At thesametimetake thetemper-
ature of the cell.
B. Temperature correct each cell reading. For each
10
o
F(5.5
o
C) above 80
o
F (26.7
o
C) add 0.004 to the
specificgravityreading.Foreach10
o
F(5.5
o
C)below
80
o
F (26.7
o
C) subtract 0.004 from the specific grav-
ity reading.
Example: Cell Temperature 100
o
F
Cell Specific Gravity 1.245
100
o
F minus 80
o
F equals 20
o
F
(37.7
o
C minus 26.7
o
C equals 11.0
o
C)
20
o
F multiply by 0.004/10
o
F equals 0.008
(11
o
C multiply by 0.004/5.5
o
C equals 0.008)
ADD (conversion above) 0.008
Correction to 80
o
F (26.7
o
C) 1.253
C. If the difference between the highest and lowest
cell specific gravity is 0.050 or greater or the lowest
cellspecificgravityislessthan 1.225,charge the bat-
tery.Chargeattherecommendedrateandtimegiven
in Charging or until all cells specific gravity is 1.225
or greater with the difference in specific gravity be-
tween 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 test with an adjustable
load tester.
Thisisone of the mostreliablemeansoftesting a battery
asitsimulates thecold--crankingtest.A commercial bat-
tery load tester is required to perform this test.
CAUTION
Follow t he manufacturer’sinstructions when us-
ing a battery load tester.
A. Check the voltage across the battery terminals
prior to testing the battery. If the voltage is less than
12.4 VDC, charge the battery.
B. If the battery has been charged, apply a 150 amp
load for 15 seconds to remove the surface charge.
Usea battery load tester following the manufactur-
er’s instructions.
C. Make sure battery terminals are free of corrosion.
D. If battery filler c aps are removable, measure the
temperature of the center cell.
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 testload of 270amps (onehalftheCrank-
ing Performance rating of the battery) for 15 se-
conds.
G. Take a battery voltage reading at 15 seconds,
then remove the load.
H. Using the table below, determine the minimum
voltage for the cell temperature reading.
Minimum
Voltage
Battery Electrolyte
Temperature
9.6 70
o
F (and up) 21.1
o
C (and up)
9.5 60
o
F 15.6
o
C
9.4 50
o
F 10.0
o
C
9.3 40
o
F 4.4
o
C
9.1 30
o
F -- 1 . 1
o
C
8.9 20
o
F -- 6 . 7
o
C
8.7 10
o
F --12.2
o
C
8.5 0
o
F --17.8
o
C
I. If the measured battery voltage is below the mini-
mum voltage shown in the table, replace the battery.
If the measured voltage is at or above the minimum
voltage shown in the table, return the battery to ser-
vice.
Electrical
System