BCI Battery TechnicalManual BCIS-05 REV DEC02 Issued Current Revision: 1993-05 2002-12 BCI SPECIFICATIONS FOR ELECTRIC VEHICLE BATTERIES SCOPE AND CLASSIFICATION 1.1 The purpose of this specification is to provide a method for rating and capacity testing Electrical Vehicle and Cycling batteries, covering time-rates commonly required for these applications A method is outlined for testing a battery; it follows that the method is intended both for the battery manufacturer to 1) use to establish ratings and newly designed batteries; and 2) monitor performance of such batteries in production It also provides a test method for the user 1.2 These batteries include lead-acid types and are used in the following applications: floor scrubbers, golf cars, personnel carriers, trolling, small mine tractors, over the road vehicles, and other deep cycling applications Not included are traction (industrial) batteries, defined as those intended for installation in mechanical handling equipment 1.3 Performance at all times rates – from though hours shall be established by testing batteries at rates which will obtain discharge times from through hours at 27°C to a final voltage of 1.75 times the number of cells Performance is to be expressed in the form of a log-log scale, plotting rate of discharge vs time of discharge Average voltages are also recorded as an option in order that watt hour capacity may be readily calculated 1.4 Performance may then be used to determine rating, or to confirm an established rating An example of log-log performance curve is shown in Figure BCIS-05 Rev DEC02 Figure Performance of Tested Group GC2 Battery CAPACITY TEST CONDITIONS 2.1 Pretest Conditioning Procedure All industry sanctioned and approved standards are established on new (60 days or less since date of manufacture), fully charged batteries The following conditioning procedure has been established as requirement prior to laboratory testing The batteries shall be charged at a rate in amperes equal to 3% of rated or expected hour capacity in ampere hours, until all cells are gassing freely, and charge voltage and specific gravity of electrolyte are constant over three successive readings taken at one hour intervals Alternately, batteries may be charged at a tapered rate, starting at a current not to exceed 20% of the 6-hour capacity, finishing at 3% miximum, or as specified by the manufacturer 2.2 Final Discharge Voltage The final voltage, when discharge is terminated, shall be 1.75 times the number of cells, for all tests in the 1-6 hour time range 2.3 Temperature Electrolyte temperature shall be 26.7°C ± 3°C (80.6°F ± 5.4°F) at start test, except when performance at other temperature is to be determined Ambient shall be a water bath at 26.7°C ± 3°C (80°F ± 5.4°F) Temperature correction may be required; this is to be determined When performance at other temperatures is to be measured, electrolyte temperatures shall be subject to the same range 2.4 Specific Gravity Electrolyte shall have a specific gravity of 1.265 ± 005, fully charged at 26.7°C (80°F) unless otherwise specified BCIS-05 Rev DEC02 2.5 Readings All voltage, specific gravity and temperature readings shall be taken from the positive terminal cell to the negative terminal cell, recorded in series and numbered 2.6 Test Equipment All equipment shall be clean, in good working order and calibrated 2.6.1 Thermometers Shall be graduated so that each scale division will not represent more than 1°C (1.8°F) and shall have an accuracy of ± 1°C (1.8°F) 2.6.2 Hydrometers Shall be graduated so that each scale division will not represent more than 0.005 units of specific gravity and shall be accurate to at least 0.005 units 2.6.3 Instrumentation Voltage and current readings shall be made with instruments capable of an accuracy of 0.1 ampere and 1% of voltage reading or better Timers shall be graduated so that each division will represent not more than one minute and during a 360 minute period shall have an accuracy within ± minutes BCIS-05 Rev DEC02 TEST METHODS 3.1 The following shall be recorded at the completion of the charge: On-charge voltage, charging rate, temperature and specific gravity 3.2 Discharge rate of the first test shall be the hour rate, either from an existing rating or from a calculated hour rate If none of this information is available, use 75 amperes or other reasonable approximation depending on battery size From results of this test, an approximate hour test rate can be determined See footnote (5.1) 3.3 When all requirements of Test Conditions have been met, the test discharge shall be initiated, within 24 hours after preconditioning 3.4 The constant discharge current shall be maintained within ± 1%of the rate in amperes for the rated discharge being performed, and is to continue until battery voltage at the terminals equals 1.75 times the number of cells 3.5 The elapsed time to final voltage shall be recorded 3.6 If watt hours are to be measured, then voltage of the battery shall be recorded continuously From this record an arithmetic average voltage can be computed from at least 10 equally time spaced voltage measurements which include beginning and end discharge points 3.7 Within minutes after completion of the test discharge, temperature and specific gravity of electrolyte of all cells shall be recorded Temperature correction of capacity is not yet established 3.8 Ampere hourscapacity shall be the product of discharge rate in amperes multiplied by time in decimal hours required to reach final voltage 3.9 Watt-hour capacity shall be the product of ampere-hours capacity multiplied by average voltage computed in Step 3.6 3.10 Battery shall be recharged as specified under Pretest Conditioning Procedure 3.11 Characterization testing sequence 3.11.1.1 A series of three tests are to be performed and plotted to establish the battery performance These tests are nominal one, three and six hour discharge tests 3.11.1.2 The battery to be measured will be given a three hour capacity test Further conditioning three hour capacity tests up to 15 cycles may be given if desired 3.11.1.3 After the three hour performance level has been achieved, a six hour capacity test will be performed, followed by the one hour capacity test The six hour and one hour tests may be repeated twice if necessary 3.11.1.4 For specific applications, the desired rate only may be run BCIS-05 Rev DEC02 PERFORMANCE LINE 4.1 The highest value obtained from each of the one, three and six hour capacity tests will be plotted on a log-log scale to establish the battery performance Units are amperes discharge rate vs time Times must not necessarily be exactly one, three and six hours, but shall be plotted for their actual yield in time 4.2 The plotted performance line is then considered the measured performance of the tested battery at 26.7°C or at the temperature at which the test was conducted This line may be used to determine minutes run vs discharge rate in the 1-6 hour range BCIS-05 Rev DEC02 COMPLIANCE STANDARDS When evaluated in accordance with accepted statistical sampling procedures, 90% of the batteries produced should meet their 1-6 hour ratings 5.1 Footnote: Ampere Hour Capacity Relationships For guidance in establishing rates, ampere hour capacity relationships are approximately: 20 hour hour hour hour 125% 100% 95% 89% hour 82% hour 72% hour 55% ... Gravity Electrolyte shall have a specific gravity of 1.265 ± 005, fully charged at 26.7°C (80°F) unless otherwise specified BCIS -05 Rev DEC02 2.5 Readings All voltage, specific gravity and temperature... graduated so that each scale division will not represent more than 0. 005 units of specific gravity and shall be accurate to at least 0. 005 units 2.6.3 Instrumentation Voltage and current readings shall...BCIS -05 Rev DEC02 Figure Performance of Tested Group GC2 Battery CAPACITY TEST CONDITIONS 2.1 Pretest