Interpretation Of Hydrometer Readings; Discharge (Load) Test; Preparation For Discharge Test; Interpretation Of Discharge Test Results - Columbia ParCar P4G Service Manual

Interpretation of Hydrometer Readings

State of charge: Check specific gravity of each cell. Refer
to Tables 6 and 7.
Specific Gravity
Reading at 80ºF
1.250-1.270
1.220-1.240
1.190-1.210
1.160-1.180
Condition: If the difference between the highest and low-
est cell is .050 (50 points) or more, the battery is nearing
the end of its useful life and should be replaced.
Note: If the highest cell reads less than 1.200, the test for
condition is questionable. Recharge battery, and perform
test again.

Discharge (Load) Test

The discharge, or load test, is the recommended method
of determining battery condition because it simulates golf
car operation under controlled conditions. A 75 amp draw
is applied to the battery bank with a Load Tester. The time
it takes the battery bank to drop to 31.5 volts, along with
individual battery voltages, is used to determine battery
condition.
Note: Use of automotive type of load tester is not
recommended and will offer inaccurate results.

Preparation for Discharge Test

The following preparations must be verified before dis-
charged load testing. Should any of the following recom-
mendations not be performed, results of testing will be
inaccurate and misleading.
a. Batteries must receive a full charge before conducting
Discharge (Load) Test.
Specific Gravity Reading Each Cell at 80º F
Battery
1
2
3
4
Table 6
State of
Charge
100%
75%
50%
25%
1 2
1.100 1.100
1.260 1.180
1.250 1.260
1.190 1.170
b. Discharge (Load) Test must be performed within 18
hours of charging.
c. Vehicle must not be used, even for short runs, prior to
Discharge (Load) Test.
d. Electrolyte level must be correct in all cells.
Discharge (Load) Test Procedure
Caution: Discharge Load Test must be performed
in well ventilated area.
a. Connect tester leads to battery bank.
b. Check and record electrolyte temperature of center
cell of each battery.
c. Turn tester on.
d. After 20-30 minutes, with tester on, check and record
individual battery voltages to the nearest .1 (1/10) volt.
Note: All six individual battery voltage readings must be
made as rapidly as possible to be accurate.
e. Allow tester to shut off automatically, and record time
elapsed from start of discharge.
Note: Tester shutoff should occur at a battery voltage of
31.5v +/- .2v. Check tester shutoff voltage periodically.
This setting must be accurate for a valid test.

Interpretation of Discharge Test Results

a. Compare individual battery voltages recorded in Step
'd' of Discharge (Load) Test Procedure and discard
any battery that is .2 (2/10) volt lower than the highest
battery in bank. If defective battery is found, recharge
the entire bank for 12 hours. Then, replace the defec-
tive battery with a good fully charged battery of the
same brand and date code, if possible. Equalize the
bank by placing it on charge for an additional three
hours, then retest.
b. If all battery voltages are within .2 volts of each other,
compare discharge time from Step 'd' of Discharge
(Load) Test Procedure with minimum times in Table 8.
Table 7
3
1.100
1.250
1.250
1.120
8-19
Required Action
Charge and recheck
Bad cell (2) replace battery
Good
Charge and recheck (suspect cell #3)