45
Rev.12/31/97
Percent Capacity =
actual time
rated time
x 100
correction factor for electrolyte temperature. Contact the manufacturer or
consult the instruction manual for correct data for the specific battery to be
tested.
consult the instruction manual for correct data for the specific battery to be
tested.
1. Set up the instrumentation to measure time, test current, and the
required voltages.
2. Disconnect the charger, connect the test load, and maintain the constant
current discharge for the duration of the test. Begin timing the test when
the discharge current begins.
the discharge current begins.
3. Read and record individual cell voltages and the battery terminal voltage
as soon as possible after the discharge begins. Repeat the readings at the
required intervals and just before completion of the test with the rated
discharge load connected. At least three sets of readings should be taken
at rated discharge current flow. More readings are preferred. Individual
required intervals and just before completion of the test with the rated
discharge load connected. At least three sets of readings should be taken
at rated discharge current flow. More readings are preferred. Individual
cell voltages should be taken between like polarity posts of adjacent cells
to include the voltage drops of intercell connections.
4. Maintain the discharge and record the elapsed time at the point when
terminal voltage decreases to the manufacturer's specified minimum
volts per cell, usually 1.00 volt times the number of cells. If one or more
cells approach polarity reversal before the specified test time, continue
the test for the originally planned test time. Ni-cad cells are not damaged
as a result of polarity reversal, so bypassing weak cells is unnecessary.
Contact the manufacturer if the battery fails the test, that is, if the
specified terminal voltage (1.00 volt per cell) is reached prior to the
specified test time.
volts per cell, usually 1.00 volt times the number of cells. If one or more
cells approach polarity reversal before the specified test time, continue
the test for the originally planned test time. Ni-cad cells are not damaged
as a result of polarity reversal, so bypassing weak cells is unnecessary.
Contact the manufacturer if the battery fails the test, that is, if the
specified terminal voltage (1.00 volt per cell) is reached prior to the
specified test time.
5.
Battery capacity can then be calculated by dividing the
actual time
to reach
specified terminal voltage by the
rated time
to specified terminal voltage
and multiplying by 100.
B. Five-Year Capacity Discharge Test
B. Five-Year Capacity Discharge Test
Perform this test every 5 years as in step A above. A battery capacity of 90
percent or less than rated capacity indicates that the battery is reaching the
end of its service life. A battery that falls to 90-percent capacity must be
tested annually as in step C below.
percent or less than rated capacity indicates that the battery is reaching the
end of its service life. A battery that falls to 90-percent capacity must be
tested annually as in step C below.
C. Annual Capacity Discharge Test
C. Annual Capacity Discharge Test
Perform capacity discharge tests annually after the capacity falls to 90
percent as revealed in the 5-year test in step B above. Replace the battery as
soon as possible after the capacity falls to 75 percent.
percent as revealed in the 5-year test in step B above. Replace the battery as
soon as possible after the capacity falls to 75 percent.