Service Manual

Groundsmaster 360 Page 5 − 61 Electrical System
(Rev. A)
Battery Testing
1. 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
100F minus 80F equals 20F
(38C minus 27C equals 11C)
20F multiply by 0.004/10F equals 0.008
(11C multiply by 0.004/5.5C equals 0.008)
ADD (conversion above) 0.008
Correction to 80F (27C) 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 cannot be met, replace
the battery.
2. 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 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 before proceeding with
test.
B. Make sure battery terminals are free of corrosion.
C. Measure the electrolyte temperature of the cen-
ter battery cell.
D. Connect a battery load tester to the battery termi-
nals following the manufacturer’s instructions.
Connect a digital multimeter to the battery terminals.
E. If the battery has recently been charged, apply a
150 amp load for fifteen (15) seconds to remove the
surface charge. Wait ten (10) minutes before pro-
ceeding with load test.
F. Apply a test load of 270 amps (one half of the bat-
tery cranking performance rating) for fifteen (15) se-
conds.
G. After test load has been applied for fifteen (15) se-
conds, take the test voltage reading and then re-
move the load. Record test voltage reading.
H. Using the table below, determine the minimum
voltage based on the center cell electrolyte tempera-
ture reading.
Minimum
Voltage
Battery Electrolyte
Temperature
9.6 70F (and up) 21C (and up)
9.5 60F 16C
9.4 50F 10C
9.3 40F 4C
9.1 30F −1C
8.9 20F −7C
8.7 10F −12C
8.5 0F −18C
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.
3. After connections are made, apply battery terminal
protector (Toro Part No. 107−0392) or a light coat of
grease on all battery posts and cable connectors to re-
duce corrosion.
Electrical
System