Toro Groundsmaster 328-D, Service Manual

Page: 195 / 402

2. 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
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) be-
low 80
o
F (26.7
o
C) subtract 0.004 from the specific
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 specific gravity of all cells
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.
3. Perform a high–discharge test with an adjustable
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 manufacturer’s instructions when
using a battery 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.
B. 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.
C. Make sure the battery terminals are free of corro-
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. Apply a test load of one half the Cranking Perfor-
mance rating of the battery for 15 seconds.
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. If the test voltage is at or above the mini-
mum, return the battery to service.
Groundsmaster 300 Series Page 6A – 13 Electrical System (Rev. G)