b. Periodically determine whether the performance of the battery is within acceptable limits.
c. If required, determine whether the battery, as found, meets the design requirements of the system to which it is connected.
Among the tests we offer for acid batteries in Stationary Applications:
An acceptance test of the battery capacity should be made at the manufacturer’s factory or upon initial installation, as determined by the user. The test should meet a specific discharge rate and duration relating to the manufacturer’s rating or to the purchase specification’s requirements. An acceptance test could establish the baseline capacity for trending purposes.
A performance test of the battery capacity should be made within the first two years of service. It is desirable for comparison purposes that the performance tests be similar in duration to the battery duty cycle. Batteries should undergo additional performance tests periodically. When establishing the interval between tests, factors such as design life and operating temperature should be considered. It is recommended that the performance test interval should not be greater than 25% of the expected service life. Annual performance tests of battery capacity should be made on any battery that shows signs of degradation or has reached 85% of the service life expected for the application. Degradation is indicated when the battery capacity drops by more than 10% from its capacity on the previous performance test or is below 90% of the manufacturer’s rating. If the battery has reached 85% of service life, delivers a capacity of 100% or greater of the manufacturers rated capacity, and has shown no signs of degradation, performance testing at two-year intervals is acceptable until the battery shows signs of degradation. If capacity is calculated by the rate-adjusted method, degradation can be indicated by a capacity drop of less than 10% from the previous test, depending on the discharge rate. Contact the manufacturer for further guidance.
A service test of the battery capability may be required by the user to meet a specific application requirement. This is a test of the battery’s ability, as found, to satisfy the battery duty cycle. A service test should be scheduled at the discretion of the user at periodic times between performance tests. When a service test is also being used on a regular basis, it will reflect maintenance practices. When a battery has shown signs of degradation, service testing should be performed on its normal frequency, and performance testing should be performed on an annual basis.
Modified performance test
A modified performance test is a test of battery capacity using a constant current modified by increasing the current to bound the currents in the duty cycle. The locations and duration of the changes in current levels could have profound effects on the battery’s ability to maintain its minimum required voltage. Initial conditions for the modified performance test should be identical to those specified for a service test. The system designer and the battery manufacturer should review the design load requirements to determine if the modified performance test is applicable and to determine the test procedure.