Technical manual section 04

The COLD CRANKING PERFORMANCE 0°F RATING is the discharge load in amperes which a new fully charged battery at 0°F -17.8°C can continuously deliver for 30 seconds and maintain a terminal

BCI Battery Technical Manual

DEC02

Current Revision: 2002-12 Approval Submission: 2001-11

BCI RECOMMENDED STORAGE BATTERY SPECIFICATIONS

STARTING, LIGHTING AND IGNITION TYPES

These procedures are for testing lead-acid storage batteries intended for starting, lighting and

ignition service in passenger cars, commercial vehicles and off-highway vehicles which are

equipped with voltage regulated charging systems

1.2 Field of Application :

The purpose of testing may be to establish and declare performance ratings which allow

match of product to application; to verify declared performance; to measure aspects of quality

control; to compare products different in design or construction; and/or to evaluate

developments in material, design and manufacturing methods These procedures focus on

flooded lead acid batteries Modifications are noted for testing valve regulated lead acid

(VRLA) batteries of either gelled or absorbed glass design

1.3 Product Classification :

Whatever the purpose, the procedures provide standard methods of measuring recognized

battery performance criteria However, the interpretation of results must take into account

test sample size and be carried out using accepted norms of statistical practice

Though the procedures may be used to assess performance loss due to the service or

storage, it must be recognized that tests, if conducted to verify achievement of declared

performance ratings, must be carried out on products which were new at the start of any test

sequence Batteries should be unused and undamaged with no previous performance

testing, and be no less than seven and no more than sixty days from date of manufacture

2 REFERENCES :

2.1 Definitions

2.1.1 RESERVE CAPACITY RATING is expressed as the number of minutes to reach 1.75 V/cell

when a new fully charged battery at 80°F (26.7°C) is continuously discharged at 25 A

2.1.2 The COLD CRANKING PERFORMANCE (0°F) RATING is the discharge load in amperes

which a new fully charged battery at 0°F (-17.8°C) can continuously deliver for 30 seconds and maintain a terminal voltage equal to or higher than 1.20 volts per cell

2.1.3 This VIBRATION TEST is to determine the ability of a battery to withstand G-levels similar to

those developed in on-road applications of passenger car and light truck vehicles without suffering mechanical damage, loss of capacity, or loss of electrolyte For batteries designed for off- road applications, SAE J930 may apply

3 PRETEST CONDITIONING AND CHARGING:

3.1 Dry Charged or Similar Batteries Which Need Electrolyte to Activate:

For the Cold Activation test, fill batteries in accordance with the specific test procedure Fill others, not to be subjected to the Cold Activation Test, according to the manufacturers' directions and then treat them as any other filled and charged battery in pretest conditioning 3.2 Filled and Charged Batteries, With Cell Access:

Addition of water to replace that lost during a test sequence is permitted if recommended by the manufacturer No other adjustments to acid strength or electrolyte volume are allowed 3.3 Filled and Charged Batteries, Without Cell Access:

In batteries, which operate with excess liquid electrolyte, provision to measure specific gravities and temperatures is to be made by carefully cutting holes through the cover in locations recommended by the manufacturer These holes must be capable of being closed

to retain integrity of the venting system Batteries shall be tested with the electrolyte

concentration as supplied by the manufacturer Adjustments to electrolyte strength or volume

in such batteries are not permitted during preparation or testing

VRLA batteries have no provision for directly reading electrolyte specific gravities or

temperatures For VRLA batteries, charging and testing temperatures must be carefully regulated The internal temperature of the battery will be considered to be equal to the temperature of the negative post, except in cases where the manufacturer has molded a deep pocket into the cover for the insertion of a temperature probe

3.5 Corrections to Specific Gravity and Voltage Readings for Temperature Changes:

3.5.1 Electrolyte Specific Gravitites:

Specific gravity comparies the weight of a substance to the weight of an equal volume of pur 80°F (26.7°C) water Electrolyte specific gravities are specified at a standard temperature of 80°F (26.7°C) Specific gravity decreases as liquid temperature increases, and vice versa Test measurements made at other temperatures (T) must be corrected to the standard temperature using the following formula:

3.5.1.1 Fahrenheit Correction:

Specific Gravity at 80°F = measured value + 0.0004 (T-80)

3.5.1.2 Celsius Correction:

Specific Gravity at 26.7°C = measured value + 0.0007 (T-26.7)

3.5.2 On-charge terminal voltage for constant current charging :

The on-charge terminal voltage for constant current charging is specified at a standard temperature of 80°F (26.7°C) It must be reduced with increased temperature and vice-versa, using the following formula:

3.5.2.1 Fahrenheit Correction:

Terminal Voltage at 80°F = reading – [No Cells x 0.0035 (T-80)]

3.5.2.2 Celsius Correction:

Terminal Voltage at 26.7°C = reading – [No Cells x 0.0063 (T-26.7)]

3.5.3 Corrections must not be made to open-circuit voltage readings or to voltages measured

during discharge

3.6 Charging Temperature:

Charging must not be started if electrolyte temperature is below 60°F (15.6°C) During charge, the temperature must be maintained between 60°F (15.6°C) and 110°F (43.3°C) 3.7 Constant Current Charging :

Prior to starting a constant current recharge, calculate the ratio of Cold Cranking rating (amperes, A) divided by Reserve Capacity rating (minutes) If this ratio is greater than or equal to 5.0, the constant current is to be set at a whole ampere value that lies between 0.5% and 0.75% of the Cold Cranking Performance (0°F) rating (in amperes) Otherwise, the constant current is to be set at a whole number ampere value between 0.75% and 1% of the Cold Cranking Performance (0°F) rating

3.7.1 The appropriate constant current must be continued until the criteria establishing full charge

are achieved, for a predetermined time, or to a predetermined percentage of overcharge specified by the manufacturer

3.7.2 Batteries that are similar in design and that are discharged to the same extent may be series

connected for recharge up to the voltage capacity of the charger unit

3.7.3 Full charge indications

For a flooded battery, two basic criteria may be used to recognize when the battery is fully charged:

3.7.3.1 When the specific gravity of the electrolyte is constant within ± 0.002 over three consecutive

one-hour intervals

3.7.3.2 When the on charge terminal voltage at the constant current does not change by more than

0.008 volts per cell per hour over three consecutive hourly intervals

3.7.3.3 The readings must be corrected to 80°F (26.7°C) to eliminate the effects of changing

temperatures

3.7.3.4 The criterion of constant cell specific gravity readings can only be used in those batteries

which incorporate liquid electrolyte and have provisions for cell access

3.7.4 When preparing and testing VRLA batteries follow the manufacturer's instructions to achieve

and recognize a full charge VRLA batteries are generally not charged by constant current methods

3.8 Constant Voltage, Current Limited, Charging :

Prior to starting constant voltage charging, the correct applied voltage for the battery must be known Applied voltages will need to be selected between 2.30 - 2.75 V/cell as battery types

and designs differ When the correct applied voltage is not known, testing laboratories should request information on voltage and charging times from the battery manufacturer

3.8.1 For constant voltage charging the charger output must be capable of at least 25 amperes per

battery

3.8.2 Equalizing charge:

An equalizing charge at the appropriate constant current rate is allowed, in conjunction with constant voltage charging, to promote electrolyte mixing and insure complete recharge The equalizing charge must not exceed 3 hours and should be used cautiously to avoid excessive overcharge For VRLA batteries, no equalizing charge should be used unless specifically recommended by the manufacturer In such cases, the manufacturer’s instructions regarding current rate and charging time will be followed

3.8.3 The appropriate constant voltage must be continued until the criteria establishing full charge

are achieved, for a predetermined time, or to a predetermined percentage of overcharge specified by the manufacturer

3.8.4 NOTE: The typical constant voltage time required following cold cranking is 12 hours and

following reserve capacity is 24 hours plus any equalizing charge

3.8.5 Determining fully charged state in flooded batteries:

For flooded batteries, two basic criteria may be used to recognize when the battery is fully charged:

3.8.5.1 When the specific gravity of the electrolyte is constant within ± 0.002 over three consecutive

hourly intervals The criterion of constant cell specific gravity readings can only be used in flooded batteries that incorporate excess liquid electrolyte and have provision for cell access The specific gravity readings must corrected to 80°F (26.7°C) to eliminate the effects of changing temperature

3.8.5.2 When a constant current is observed over three consecutive one-hour intervals at a constant

terminal voltage

3.8.6 When preparing and testing VRLA batteries that have gelled or absorbed electrolyte, follow

the manufacturer's instructions to achieve and recognize full charge Batteries of the same design and that are discharged to approximately the same extent may be series connected for recharge within the voltage capability of the charger unit Batteries may also be parallel connected to a common voltage bus-bar system if the total current supply is adequate In either case of multiple unit charging, individual unit control to full charge is essential

3.8.7 Batteries of the same design that are discharged to the same extent may be series

connected for recharge within the voltage capability of the charger unit Batteries may be parallel connected to a common voltage bus-bar system if the total current supply is

adequate In either case of multiple unit charging, individual unit control to full charge is essential

3.9 Stand Time After Charging :

At the end of a charge, batteries will be polarized above normal open circuit values and may

be at a temperature which is higher than that specified for the subsequent test A period to allow depolarization and cooling will be necessary Minimum and maximum stand times between end of charge and beginning of test are detailed in each of the test procedures

4 TEST SEQUENCE :

4.1 Depending upon the objective of testing, because of the time needed to complete some tests,

and their effect on on-going battery performance, testing sequences for discrete sets of batteries must be adopted according to the chart given below Repeat tests of Reserve Capacity and Cranking Performance are required only if the rated values were not achieved initially

Rated

Vibration Resistance

Table 1

5 MEASUREMENTS OF BATTERY PERFORMANCE :

5.1 Battery Performance Characteristics

To provide meaningful measurements of battery performance to the end user, battery

engineers, supported by BCI (Battery Council International) and SAE (Society of Automotive Engineers), established two methods of expressing the performance characteristics of a battery capacity for engine cranking for starting and capacity for ignition, lighting and other accessories required in emergencies

5.2 Reserve Capacity Test Procedure:

A battery may have to provide current for ignition and lighting in the event of failure in the vehicle's electricity generating system This test provides a measurement of its potential capacity to provide that power in terms of a comparative rating

5.2.1 When preparing and testing VRLA batteries that have gelled or absorbed electrolyte, follow

the manufacturer's instructions to achieve and recognize full charge

5.2.2 Fully charge the battery according to the "Pretest Conditioning and Charging Procedure" and

allow it to stand no less than 4 hours or no more than 96 hours before the start of discharge

5.2.3 During the stand period, regulate battery temperature so that electrolyte temperature,

measured above the plates in an intermediate cell, is stabilized at 80 ± 5°F (26.7 ± 2.8°C) before the start of the discharge The electrolyte temperature of a VRLA battery prior to the start of the discharge will be considered to be equal to the temperature of the negative post, except in cases where the manufacturer has molded a deep pocket into the cover for the insertion of a temperature probe

5.2.4 Discharge the battery at 25 ± 0.25 A During discharge, using any convenient method,

maintain electrolyte temperatures within the range 75°F (23.9°C) to 90°F (32.2°C) Results will not be considered valid if electrolyte temperatures move outside this range before the end

of the discharge

5.2.5 End the discharge when the voltage across the battery terminals has fallen to the equivalent

of 1.75 V/cell, noting the discharge duration in minutes and the electrolyte temperature at the cut-off point

5.2.6 Correct the discharge duration for final temperatures different from 80°F (26.7°C) using the

formulas, which follow and record the corrected time as the Reserve Capacity achieved 5.2.6.1 Fahrenheit Correction:

Mc, = Mr, [1 - 0.005 (T-80)]

5.2.6.2 Celsius Correction:

Mc = Mr, [1 - 0.009 (T-26.7)]

Where: Mc, = minutes corrected to 80°F (26.7°C)

Mr, = minutes actually run

T = end of discharge electrolyte temperature (°F) or (°C) 5.3 Cranking Performance:

The primary function of a battery is the provision of power to crank the engine during starting This requires a short discharge at very high current and adequate voltage

5.3.1 WARNING -New, fully charged high-performance batteries can deliver significantly higher

than rated discharge currents, particularly at elevated temperatures Therefore, care must be exercised during laboratory testing to avoid discharges above the rated current, temperature

or duration, which could cause melting of terminal or internal connections that, may result in explosion of the battery Make sure that test batteries are properly filled with electrolyte Do not connect cables to the battery terminals using light spring clips, which inadequately conduct away generated heat Do not discharge batteries at currents greater than the manufacturers rating

5.3.2 Fully charge the battery according to the "Pretest Conditioning and Charging” procedure and

allow it to stand at room temperature for 8 to 96 hours before starting to cool it

5.3.3 Place the battery in a cold chamber held at a temperature between –2°F and 0°F (-19°C and

-17.8°C) for the Cold Cranking Performance (0°F) test for at least 16 hours, until the

electrolyte temperature measured above the plates in an intermediate cell, has stabilized at the test temperature of 0°F ± 1°F (-17.8°C ± 0.6°C) The electrolyte temperature of a VRLA battery prior to the start of the discharge will be considered to be equal to the temperature of the negative post, except in cases where the manufacturer has molded a deep pocket into the cover for the insertion of a temperature probe

5.3.4 With the battery still in the cold chamber, discharge the battery at the rating current The

discharge current must be controlled within ± 2 A

5.3.5 At 30 seconds after the start of the discharge, measure and record the terminal voltage of the

battery under load This must not be less than the equivalent of 1.20 V/cell Iff the voltage falls below 1.20 V/cell before 30 seconds has elapsed, stop discharge Record time to 1.20 V/cell

5.3.6 NOTE: The test is not invalidated if the electrolyte temperature rises above the designated

temperature during the 30 second period, as a result of the high discharge current

6 STANDARDS OF COMPLIANCE TO PERFORMANCE RATINGS :

6.1 When statistically evaluated in accordance with accepted sampling and testing procedures,

90% of all batteries should be expected to meet or exceed the Reserve Capacity Rating and 90% should be expected to meet or exceed the Cranking Performance Rating, based on each battery's best performance within a test sequence

6.2 Compliance to Reserve Capacity Rating and to Cranking Performance Rating should be

evaluated separately

6.3 Batteries that fail to reach rated performance values during electrical tests should be checked

for mechanical defects If any are defective, the test results for that battery should be

disregarded in statistical analysis

7 COLD ACTIVATION PERFORMANCE :

Even in a very well prepared dry-charged battery, the capacity in the plates cannot be 100%

of their full capacity Also, the capacity retained over a period of time is affected by storage conditions, which are often outside the control of the manufacturer The Cold Activation Test provides a collective measure of effectiveness in processing, charge retention and the ability

of a battery to activate when placed in service under cold weather conditions

7.1 Use electrolyte for filling which has a specific gravity of 1.265 ± 005 at 80°F (26.7°C) or as

specified by the manufacturer

7.2 Place the battery and the electrolyte separately in a chamber cooled to 30°F ± 2°F (-1.1°C ±

1.1°C) for a minimum of 18 hours Verify that the electrolyte temperature has fallen to 30°F ± 2°F (-1.1°C ± 1.1°C) before using it to fill the battery

7.3 Remove the battery and electrolyte from the cold chamber Without delay fill each cell in the

battery to the correct level

7.4 Allow the battery to stand for 20 minutes outside the cold chamber after complete filling of the

last cell A temperature rise is to be expected and does not invalidate the test

7.5 Discharge the battery at a current rate equal to 75% of the Cold Cranking Performance

Rating for the battery Measure and record the terminal voltage of the battery under load after

15 seconds of discharge

7.6 The battery is considered to meet minimum specification requirements if the terminal voltage

measured at 15 seconds is at least equal to 1.20 V/cell