Service Manual

Groundsmaster 580--D
Page 8 -- 16
Electrical System (S/N 30101 & Up) (Rev. E)
2. Conductahydrometertestofthebatteryelectrolyte.
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
hydrometerbarrel prior totaking areading to warm--
upthehydrometer.Atthesametimetakethetem-
perature of the cell.
B. Temperature correct each cell reading. Foreach
10
o
F(5.5
o
C) above 80_F (26.7
o
C) add 0.004 to
the specific gravity reading. For each 10
o
F(5.5
o
C)
below 80
o
F (26.7
o
C) subtract 0.004 from the spe-
cific gravity reading.
Example: Cell Temperature 100
o
F
Cell Gravity 1.245
ADD (20
o
above 80
o
F) 0.008
Correction to 80
o
F 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
battery. Charge at the recommended rate and time
given in Charging or until all cells specific gravity is
1.225 or greater with the difference in specific grav-
ity between the highest and lowest cell less than
0.050. If these charging conditions can not be met,
replace the battery.
3. Perform a high--discharge test with an adjustable
load tester.
Thisisoneofthe mostreliablemeansoftesting a battery
asitsimulates thecold--cranking test.Acommercialbat-
tery load tester is required to perform this test.
CAUTION
Follow the manufacturer’s instructions when
using a battery 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.
B. Ifthe batteryhasbeencharged, applya150 amp
load for 15 seconds to remove the surface charge.
Use a battery load tester following the manufactur-
er’s instructions.
C. Makesurethebatteryterminalsarefreeofcorro-
sion.
D. Measure the temperature of the center cell.
E. Connect a battery load tester to the battery ter-
minals following the manufacturer’s instruc-
tions. Connect a digital multimeter to the battery
terminals.
F. Applya test load of one half the Cranking Perfor-
mance rating (see Fig. 17) of the battery for 15 se-
conds.
G. Take a voltage reading at 15 seconds, then re-
move 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 test voltage is below the minimum, replace
the battery. Ifthe test voltage is at orabove the mini-
mum, return the battery to service.