Understanding General Requirements and Methods Of Testing Lead Acid Storage Batteries

  • All the tests covered in this standard may not be applicable to all types of Batteries.  Provisions in the individual specifications shall be applicable.

    The Specification does not cover the requirements of batteries for Applications such as Aircraft, Marine and Minors cap lamp.





    CLASSIFICATION OF TESTS:

    There are Basically 3 classes of tests:

    1. TYPE TEST

    These tests are carried out to ensure that the batteries offered are in conformity with the requirement in terms of General Quality and Design of a required type of Battery

    2. ACCEPTANCE TEST:

    These tests are carried out on samples selected from a LOT for verifying the acceptance of the LOT.

    [What comprises a LOT? All cells and Batteries of  SAME TYPE, DESIGN & RATINGS manufactured in the  SAME FACTORY during the SAME PERIOD using SAME PROCESS & MATERIALS.]

    3. ROUTINE TESTS:

    These are the test carried out on each and every battery.


    We have not considered the general and physical requirements like materials, construction, dimensions, marking & packing  and have elaborated only Electrical test.

     

    Requirement of test instruments and equipment for carrying out various electrical tests:

    1. Voltmeter:

    (An instrument to measure battery terminal voltage) – This should be of 0.5% accuracy class or better as per IS 1248.  The internal resistance of the voltmeter should be at least 1000 Ohms per volt. This could be analogue or digital type.

    2. Ammeter: 

    (An instrument to measure battery charge/discharge current) – This should be of 1.0% accuracy class or better (analogue or digital)

    3. Thermometer:

    (An instrument to measure temperature) – Thermometers of appropriate scale with least count of 1 deg C and accuracy of 0.5 deg c are required.

    4. Hydrometer:

    (An instrument used to measure specific gravity of electrolyte) – The graduations on the Hydrometer should be 0.005 units of specific gravity and accuracy of 0.005 units.

     5. Constant current discharge unit

    This is required to discharge battery at desired current which will be maintained constant at set value within +- 1% or better.  Current range will depend on the capacity of the battery to be tested.

    This unit is useful in conducting capacity test, loss of capacity test, storage test, as well as high rate discharge at normal as well as low temperatures.

    6. Constant current charger and discharger fitted with ampere hour meter or timer

    This is necessary for carrying our ampere hour and watt hour efficiency test.  This is also useful for conducting charge/discharge cyclic test (endurance and life cycle) as well as resistance to overcharge test.

    7. Constant Potential charger fitted with timer

    This is required for conducting Charge Acceptance Test & Water Loss Test.

    8. Data Acquisition system (Data loggers)

    These are essential for capturing and storing test data like battery voltage, charge/discharge current, bath temperature, electrolyte temperature, ampere hours etc at preset  time interval.


    ELECTRICAL TESTS:

    Capacity Test:

    Battery capacity is expressed in ampere hours (corrected at 27 deg C) This rating   would be obtained when the cell/battery is discharged at a specific rate till the battery  terminal voltage on load reaches specified voltage at specified specific gravity of electrolyte at the beginning  of the discharge.  The multiplication of discharge current in amps and total discharge time in hours gives the ampere hour capacity of the battery.

    Capacities at various rates of discharge like C1, C3, C5, C10 etc. are different.  These are specified in individual specifications.

    Test Procedure:

    1. Test battery is first charged fully as per manufacturers instruction and specific gravity of electrolyte in each cell is checked and adjusted if required.

    2. The fully charged battery is allowed to stand on open circuit at electrolyte temperature between 20 to35 deg C for specified time period from the time of completion of first charge.

    3. The battery is then discharged through a variable resistance (active load) at specified current which should be maintained constant within tolerance of +- 1% or better.

    4. The discharge will be stopped when close circuit voltage of battery reaches specified voltage.

    5. During discharge hourly voltage readings are taken till battery close circuit voltage reaches a specified value and there after the readings are taken at every 15 minutes till voltage false to specified end voltage.

    6. Temperature of electrolyte is taken every hour and the average temperature will be taken as the electrolyte temperature during discharge.
    7. The discharge time in hours multiplied by the discharge current in amperes will be the ampere hour capacity of the Battery at the noted average temperature which shall be corrected to 27 deg C with correction factor as give below.

    C 27   = Ct /1+0.01 (T-27)

    Requirement: The capacity in ampere hours thus obtained should be within 100-120% of rated ca

Comments

Ragu Rangaraj

hello

Ragu Rangaraj

hi
Load more comments
Newsletters Signup
Sign up to Our Newsletter & get attractive Offers by subscribing to our newsletters.