Battery Testing - Toro Groundsmaster 4700-D Service Manual

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
o o o
10 F (5.5 C) above 80
specific gravity reading. For each 10
o o
low 80 F (26.7 C) subtract 0.004 from the specific
gravity reading.
Example: Cell Temperature
Cell Gravity
o o
100 F minus 80 F equals 20
o
(37.7 C minus 26.7
o
20 F multiply by 0.004/10
o
(11 C multiply by 0.004/5.5
ADD (conversion above)
o
Correction to 80 F (26.7
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 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 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
12.4 VDC, recharge the battery.
B. If the battery has been charged, apply a 150 amp
load for fifteen (15) seconds to remove the surface
charge. Use a battery load tester following the
manufacturer's instructions.
Groundsmaster 4500--D/4700--D
o
F (26.7 C) add 0.004 to the
o o
F (5.5 C) be-
o
100 F
1.245
o
F
o o
C equals 11.0 C)
o
F equals 0.008
o
C equals 0.008)
0.008
o
C) 1.253
Page 5 - - 35
C. Make sure battery terminals are free of corrosion.
D. Measure the temperature of the center battery
cell.
E. Connect a battery load tester to the battery termi-
nals following the load tester manufacturer's in-
structions. Connect a digital multimeter to the
battery terminals.
F. Apply a test load of 325 amps (one half the Crank-
ing Performance rating of the battery) for fifteen (15)
seconds.
G. Take a battery voltage reading after the load has
been applied to the battery for fifteen (15) seconds,
then remove the load. Record the voltage reading.
H. Using the table below, determine the minimum
voltage for the cell temperature reading:
Minimum Battery Electrolyte
Voltage Temperature
o
9.6 70 F (and up)
o
9.5 60 F
o
9.4 50 F
o
9.3 40 F
o
9.1 30 F
o
8.9 20 F
o
8.7 10 F
o
8.5 0 F
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.
o
21.1 C (and up)
o
15.6 C
o
10.0 C
o
4.4 C
o
--1.1 C
o
--6.7 C
o
--12.2 C
o
--17.8 C
Electrical System