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IEEE Std 450™-
(Revision of IEEE Std 450-1995)
I
EEE Standards
TM
IEEE Recommended Practice for
Maintenance, Testing, and Replacement
of Vented Lead-Acid Batteries for
Stationary Applications
Published by The Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue, New York, NY 10016-5997, USA
3 April 2003
IEEE Power Engineering Society
Sponsored by the PES Stationary Battery Committee
IEEE Standards
Print: SH PDF: SS
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Copyright © 2003 IEEE. All rights reserved. iii
Introduction
(This introduction is not part of IEEE Std 450-2002, IEEE Recommend Practice for Maintenance, Testing, and Replace- ment of Vented Lead-Acid Batteries for Stationary Applications.)
Stationary lead-acid batteries play an ever-increasing role in industry today by providing normal control and instrumentation power and back-up energy for emergencies. This recommended practice fulfills the need within the industry to provide common or standard practices for battery maintenance, testing, and replace- ment. The installations considered herein are designed for full-float operation with a battery charger serving to maintain the battery in a charged condition as well as to supply power to the normal dc loads. However, specific applications, such as emergency lighting units and semi-portable equipment, may have other appro- priate practices that are beyond the scope of this recommended practice.
This recommended practice may be used separately, and, when combined with IEEE Std 484™-1996, IEEE Recommended Practice for Installation Design and Installation of Large Lead Storage Batteries for Generating Stations and Substations and IEEE Std 485™-1997, IEEE Recommended Practice for Sizing Vented Lead-Acid Storage Batteries for Stationary Applications, will provide the user with a general guide to sizing, designing, placing in service, maintaining, and testing a vented lead-acid storage battery installa- tion. IEEE Std 535™-1986 provides a standard for qualification of Class 1E lead storage batteries for nuclear power generating stations.
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Copyright © 2003 IEEE. All rights reserved. v
When the IEEE-SA Standards Board approved this standard on 11 December 2002, it had the following membership: James T. Carlo, Chair James H. Gurney, Vice Chair Judith Gorman, Secretary
*Member Emeritus
Also included are the following nonvoting IEEE-SA Standards Board liaisons:
Alan Cookson, NIST Representative Satish K. Aggarwal, NRC Representative
Catherine Berger IEEE Standards Project Editor
Sid Bennett H. Stephen Berger Clyde R. Camp Richard DeBlasio Harold E. Epstein Julian Forster* Howard M. Frazier
Toshio Fukuda Arnold M. Greenspan Raymond Hapeman Donald M. Heirman Richard H. Hulett Lowell G. Johnson Joseph L. Koepfinger* Peter H. Lips
Nader Mehravari Daleep C. Mohla William J. Moylan Malcolm V. Thaden Geoffrey O. Thompson Howard L. Wolfman Don Wright
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vi Copyright © 2003 IEEE. All rights reserved.
- 1. Overview.............................................................................................................................................. Contents - 1.1 Purpose......................................................................................................................................... - 1.2 Scope............................................................................................................................................ - 2. References............................................................................................................................................ - 3. Definitions............................................................................................................................................ - 4. Safety - 4.1 Protective equipment - 4.2 Precautions................................................................................................................................... - 4.3 Methods........................................................................................................................................ - 5. Maintenance......................................................................................................................................... - 5.1 General......................................................................................................................................... - 5.2 Inspections - 5.3 Corrective actions - 5.4 State of charge.............................................................................................................................. - 6. Test schedule........................................................................................................................................ - 6.1 Acceptance................................................................................................................................... - 6.2 Performance - 6.3 Service.......................................................................................................................................... - 6.4 Modified performance test........................................................................................................... - 7. Procedure for battery tests - 7.1 Initial conditions - 7.2 Test length and discharge rate.................................................................................................... - 7.3 Capacity test methods - 7.4 Acceptance, modified performance, and performance tests - 7.5 Service test - 7.6 Restoration - 8. Battery replacement criteria............................................................................................................... - 9. Records - 10. Recycling and disposal - 10.1 Recycling - 10.2 Disposal......................................................................................................................................
- Annex A (informative) State of charge - A.1 Battery discharge/charge cycle parameters........................................................................
- Provided by IHS under license with IEEE Licensee=Technip/ Copyright The Institute of Electrical and Electronics Engineers, Inc. - A.2 Stabilized charging current used to determine a fully charged condition.......................... Copyright © 2003 IEEE. All rights reserved. vii - A.3 Electrolyte specific gravity used to determine a fully charged condition.......................... - A.4 State of charge, choosing float current
- Annex B (informative) Specific gravity......................................................................................................
- B.1 Effect of charging
- B.2 Effect of temperature
- B.3 Effect of electrolyte level...................................................................................................
- B.4 Effect of water additions....................................................................................................
- Annex C (informative) Float voltage
- C.1 Low-voltage cells...............................................................................................................
- C.2 High-voltage cells
- C.3 Effect of temperature
- Annex D (informative) Urgency of corrective actions................................................................................
- D.1 Adding water......................................................................................................................
- D.2 Connection resistance
- D.3 Cell temperature.................................................................................................................
- D.4 Equalizing charge...............................................................................................................
- Annex E (informative) Visual inspection of battery installations...............................................................
- using a microohmmeter................................................................................................................ Annex F (informative) Examples of methods for performing connection resistance measurements
- a microohmmeter F.1 Recommended method for performing connection resistance measurements using
- F.2 Recommended method for single intercell connections and parallel-post connections
- F.3 Recommended method for double-post intercell connections...........................................
- F.4 Recommended method for triple-post intercell connections
- F.5 Recommended method for flag-post intercell connections
- F.6 Recommend method for single connections
- F.7 Recommended method for multiple terminal connections
- Provided by IHS under license with IEEE Licensee=Technip/ Copyright The Institute of Electrical and Electronics Engineers, Inc. - F.8 Recommended method for cable-plate-post connections viii Copyright © 2003 IEEE. All rights reserved.
- Annex G (informative) Alternate applications
- Annex H (informative) Effects of elevated electrolyte temperatures on vented lead-acid batteries...........
- Annex I (normative) Modified performance testing methods and examples
- I.1 Type 1 modified performance test
- I.2 Type 2 modified performance test
- I.3 Type 3 modified performance test
- Annex J (informative) Alternate inspection methods
- Annex K (informative) Calculation of battery capacity
- K.1 Comparison of time- and rate-adjusted performance test methods
- K.2 Capacity calculation examples...........................................................................................
- K.2.1 Example – 15-minute duty.......................................................................................
- K.2.2 Interpretation of data from tests carried out at full published rates
- K.2.3 Application of rate-adjusted method for other end-of-life conditions
- Annex L (informative) Temperature correction factors..............................................................................
- Annex M (informative) Bibliography
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Copyright © 2003 IEEE. All rights reserved. 1
IEEE Recommended Practice for
Maintenance, Testing, and Replacement
of Vented Lead-Acid Batteries for
Stationary Applications
1. Overview
1.1 Purpose
The purpose of this recommended practice is to provide the user with information and recommendations concerning the maintenance, testing, and replacement of vented lead-acid batteries used in stationary applications.
1.2 Scope
This document provides recommended maintenance, test schedules, and testing procedures that can be used to optimize the life and performance of permanently-installed, vented lead-acid storage batteries used for standby power applications. It also provides guidance to determine when batteries should be replaced. This recommended practice is applicable to full-float stationary applications where a battery charger normally maintains the battery fully charged and provides the dc loads. However, specific applications, such as emer- gency lighting units and semi-portable equipment, may have other appropriate practices that are beyond the scope of this recommended practice.
Sizing, installation, qualification, other battery types, and application are also beyond the scope of this recommended practice. The maintenance and testing programs described in this recommended practice rep- resent “the best program” based on the information available at the time this document was developed. The user should evaluate these practices against their operating experience, operating conditions, manufacturer’s recommendations, resources, and needs in developing a maintenance program for a given application. These maintenance and testing recommendations were developed without consideration of economics, availability of testing equipment and personnel, or relative importance of the application. Development of a maintenance and testing program for a specific application requires consideration of all issues, not just the technical issues considered in this document.
This recommended practice does not include any other component of the dc system, or inspection and test- ing of the dc system, even though the battery is part of that system. Pre-operational and periodic dc system tests of chargers and other dc components may require that the battery be connected to the system. Details
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IEEE OF VENTED LEAD-ACID BATTERIES FOR STATIONARY APPLICATIONS Std 450-
Copyright © 2003 IEEE. All rights reserved. 3
3.4 duty cycle: The loads a battery is expected to supply for specified time periods while maintaining a min- imum specified voltage.
3.5 equalizing voltage: The voltage, higher than float, applied to a battery to correct inequalities among battery cells (voltage or specific gravity).
3.6 float voltage: The voltage applied to a battery to maintain it in a fully charged condition during normal operation.
3.7 flooded cell: A cell in which the products of electrolysis and evaporation are allowed to escape to the atmosphere as they are generated. These batteries are also referred to as “vented.”
3.8 modified performance test: A test, in the “as found” condition, of battery capacity and the ability of the battery to satisfy the duty cycle.
3.9 performance test: A constant-current or constant-power capacity test made on a battery after it has been in service, to detect any change in the capacity.
3.10 rated capacity (lead-acid): The capacity assigned to a cell by its manufacturer for a given discharge rate, at a specified electrolyte temperature and specific gravity, to a given end-of-discharge voltage.
3.11 service test: A test in the as “found condition” of the battery’s capability to satisfy the battery duty cycle.
3.12 terminal connection: Connections made between cells or at the positive and negative terminals of the battery, which may include terminal plates, cables with lugs, and connectors.
4. Safety
WARNING BATTERIES ARE POTENTIALLY DANGEROUS AND PROPER PRECAUTIONS MUST BE OBSERVED IN HANDLING AND MAINTENANCE. WORK ON BATTERIES SHALL BE PERFORMED ONLY WITH PROPER TOOLS AND SHALL UTILIZE THE PROTECTIVE EQUIPMENT LISTED. BATTERY MAIN- TENANCE SHALL BE DONE, BY PERSONNEL KNOWLEDGEABLE OF BATTERIES AND TRAINED IN THE SAFETY PRECAUTIONS INVOLVED.
4.1 Protective equipment
The following protective equipment shall be available to personnel who perform battery maintenance work:
a) Goggles and face shields b) Acid-resistant gloves c) Protective aprons d) Portable or stationary water facilities for rinsing eyes and skin in case of contact with electrolyte e) Bicarbonate of soda solution, mixed 100 grams bicarbonate of soda to 1 liter of water, to neutralize acid spillage NOTE—The removal and/or neutralization of an acid spill may result in production of hazardous waste. The user should comply with appropriate governmental regulations.
f) Class C fire extinguisher
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IEEE Std 450-2002 IEEE RECOMMENDED PRACTICE FOR MAINTENANCE, TESTING, AND REPLACEMENT
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NOTE—Some battery manufacturers do not recommend the use of CO 2 Class C fire extinguishers due to the potential of thermal shock.
g) Adequately insulated tools NOTE—Barriers to prevent the spread of acid spills are extremely important when moving cells such as during battery installation or removal activities.
4.2 Precautions
The following protective procedures shall be observed during maintenance:
a) Use caution when working on batteries since they represent a shock hazard. b) Prohibit smoking and open flames, and avoid activities that increase the chances of arcing in the immediate vicinity of the battery. c) Ensure that the load test leads are clean, in good condition, and connected with sufficient length of cable to prevent accidental arcing in the vicinity of the battery. d) Ensure that all connections to load test equipment include appropriate short-circuit protection. e) Ensure that battery area ventilation is operating per its design. f) Ensure unobstructed egress from the battery area. g) Avoid the wearing of metallic objects such as jewelry. h) Neutralize static buildup just before working on the battery by contacting the nearest effectively grounded surface. i) If installed, ensure that the battery monitoring system is operational.
4.3 Methods
Work performed on an in-service battery shall use methods that preclude circuit interruption or arcing in the vicinity of the battery.
5. Maintenance
5.1 General
Proper maintenance will prolong the life of a battery and will aid in ensuring that it is capable of satisfying its design requirements. A good battery maintenance program will serve as a valuable aid in maximizing bat- tery life, preventing avoidable failures, and reducing premature replacement. Personnel knowledgeable of batteries and the safety precautions involved shall perform battery maintenance.
(See IEEE Std 484-1996 for initial installation requirements.)
5.2 Inspections
Implementation of periodic inspection procedures provide the user with information for determining the condition of the battery. The frequency of the inspections should be based on the nature of the application and may exceed that recommended herein. All inspections should be made under normal float conditions. For specific gravity measurements to be meaningful, the electrolyte must be fully mixed. Electrolyte mixing
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IEEE Std 450-2002 IEEE RECOMMENDED PRACTICE FOR MAINTENANCE, TESTING, AND REPLACEMENT
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5.2.4 Special inspections
If the battery has experienced an abnormal condition (such as a severe discharge or overcharge), an inspec- tion should be made to ensure that the battery has not been damaged. Include the requirements of 5.2.1, 5.2.2, and 5.2.3.
5.3 Corrective actions
The corrective actions listed in 5.3.1 through 5.3.3 are meant to provide optimum life of the battery. How- ever, the corrective actions in themselves will not guarantee that the battery is completely charged at any given time. Annex A through Annex G provide some technical background for the recommended actions and their timing, and provide other methods for determining the state of charge of a battery.
5.3.1 Cell/Battery problems
The following items indicate conditions that can be easily corrected prior to the next monthly inspection. Major deviations in any of these items may necessitate immediate action.
a) When any cell electrolyte reaches the low-level line, distilled or other approved-quality water should be added to bring the cells to the manufacturer’s recommended full level line. Water quality should be in accordance with the manufacturer’s instructions. b) If corrosion is noted, remove the visible corrosion and check the resistance of the connection. c) If resistance measurements obtained in 5.2.3, item c) or 5.3.1, item b) are more than 20% above the installation value or above a ceiling value established by the manufacturer/system designer, or if loose connections are noted, retorque and retest. If retested resistance value remains unacceptable, the connection should be disassembled, cleaned, reassembled, and retested. Refer to IEEE Std 484- 1996 for detailed procedures. See also D.2 and Annex F. d) When cell temperatures deviate more than 3 °C from each other during a single inspection, determine the cause and correct the problem. If sufficient correction cannot be made, contact the manufacturer for allowances that must be taken. NOTE—When working with large multi-tier installations, the 3°C allowable deviation may not be achievable. The user should contact the manufacturer for guidance.
e) When excessive dirt is noted on cells or connectors, remove it with a water-moistened clean wipe. Remove electrolyte spillage on cell covers and containers with a bicarbonate of soda solution mixed 100 grams of soda to 1 liter of water. Avoid the use of hydrocarbon-type cleaning agents (oil distil- lates) and strong alkaline cleaning agents, which may cause containers and covers to crack or craze. f) When the float voltage measured at the battery terminals is outside of its recommended operating range, it should be adjusted.
5.3.2 Equalizing charge
Item a) though item d) in this subclause indicate conditions that, if allowed to persist for extended periods, can reduce battery life. They do not necessarily indicate a loss of capacity. Therefore, the corrective action can be accomplished prior to the next quarterly inspection, provided that the battery condition is monitored at regular intervals (not to exceed one week). Note that an equalizing charge normally requires that equaliz- ing voltage be applied continuously for 24 hours or longer. (Refer to the manufacturer’s instructions.) Single cell charging is an acceptable method when a single cell or a small number of cells appear to need equalizing.
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IEEE OF VENTED LEAD-ACID BATTERIES FOR STATIONARY APPLICATIONS Std 450-
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a) An equalizing charge is desirable, if individual cell float voltage(s) deviate from the average value by an amount greater than that recommended by the manufacturer. Typical recommendations are ±0.05 V for lead-calcium cells and ±0.03 V for lead-antimony cells. b) An equalizing charge should be given if the specific gravity, corrected for temperature, of an individ- ual cell falls below the manufacturer’s lower limit (see D.4). c) An equalizing charge should be given immediately if any cell voltage is below the manufacturer’s recommended minimum cell voltage (see C.1). d) Some manufacturers recommend periodic equalizing charges. This equalizing charge can be waived for certain batteries based on an analysis of the records of operation and maintenance inspections (see Clause 9).
5.3.3 Other abnormalities
Correct any other abnormal conditions noted. See Annex D for a more detailed discussion of these abnor- malities and the urgency of the corrective actions.
5.4 State of charge
A fully-charged battery provides assurance that the available battery capacity will be maximized. The charge returned to the battery under constant voltage charging is linear while the charger is operating in current limit mode, and exponentially related to time when the charger comes out of current limit. The charge returned may also be affected by the charging voltage and the electrolyte temperature. Once charged, the ability of a battery to remain fully charged under float conditions is affected by the float voltage level and the electrolyte temperature. The type of cell may affect the choice of which indicator(s) to use as a measure of state of charge (see A.4).
5.4.1 State of charge indicator
The following may be used as indicators of return to a fully charged state after a discharge (see Annex A):
a) Stabilized charging current when measured at the manufacturer’s recommended voltage and temper- ature for recharging the battery. b) Assurance that the ampere hours returned to the battery are greater than the ampere hours removed plus the charging losses.
5.4.2 Charging current indicator
After the battery has been charged, stabilized charging current may be used as an indicator that the battery is fully charged (see Annex A).
5.4.3 Specific gravity indicator
Specific gravity (S.G.) may be used as an approximate indicator of full charge, if the electrolyte density is sufficiently uniform through the cell (see Annex A and Annex B). Specific gravity measurements are not as accurate for the first few weeks after a battery
— Recharge, — Equalizing charge, or — Water addition
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IEEE OF VENTED LEAD-ACID BATTERIES FOR STATIONARY APPLICATIONS Std 450-
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requirement a), perform requirement b) but take no corrective action unless there is a possibility of permanent damage to the battery, and perform requirements c) through f) of 7.1. If on a performance test that is used to reflect maintenance practices, the battery does not deliver its expected capacity, then the test should be repeated after the requirements of 7.1 a) and b) have been completed.
6.3 Service
A service test of the battery capability (see 7.5) 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 ser- vice 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.
6.4 Modified performance test
A modified performance test (see 7.4) is a test of battery capacity using a constant current, modified by increasing the current to bound the currents in the duty cycle. Deviations from the constant-current test, which increase the current, are acceptable. 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. See Annex I for typical modified performance test types and examples.
A modified performance test can be used in lieu of a service test and/or a performance test at any time. If the battery has been sized in accordance with IEEE Std 485-1997, then the battery is acceptable if it delivers a tested capacity of 80% or greater. Jumpering out cells is not allowed during the duty cycle portion (service test) of a modified performance test. Jumpering out cells is allowed after the duty cycle duration (service test) of the test is satisfied.
7. Procedure for battery tests
These procedures describe the recommended practices for discharge testing a battery. All testing should fol- low the precautions listed in 4.2.
7.1 Initial conditions
The following list gives the initial requirements for all battery capacity tests except as otherwise noted.
a) Equalize the battery if recommended by the manufacturer and then return it to float for a minimum of 72 hours. b) Check all battery connections and ensure that all resistance measurements are correct for the system [see 5.2.3 c)]. c) Record the specific gravity and float voltage of each cell or float current of the string and float volt- age of each cell just prior to the test. d) Record the electrolyte temperature of 10% or more of the cells to establish an average temperature (suggested every sixth cell).
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IEEE Std 450-2002 IEEE RECOMMENDED PRACTICE FOR MAINTENANCE, TESTING, AND REPLACEMENT
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e) Record the battery terminal float voltage. f) Take adequate precautions (such as isolating the battery to be tested from other batteries and critical loads) to ensure that a failure will not jeopardize other systems or equipment.
7.2 Test length and discharge rate
7.2.1 Test length
There are four different types of battery discharge tests presented in this document. They are as follows:
a) Acceptance b) Performance c) Modified performance d) Service tests.
Acceptance, performance and modified performance tests are all tests of a battery’s capacity. The service and modified performance tests verify the battery’s ability to meet its duty cycle.
— See 7.5 for determining the length of a service test. — The performance and acceptance tests are presented in 7.4 and the duration is recommended to be approximately the same as the duty cycle. These tests may not confirm the ability of the battery to meet its duty cycle, particularly if very high-rate, short-duration loads determine the battery size. — The modified performance test is presented in 7.4 and the recommended duration is the duty cycle multiplied by the aging factor used in sizing the battery.
7.2.2 Discharge rate
The discharge rate for a capacity test depends upon the type of capacity test selected. For the acceptance test or performance test, the discharge rate should be a constant-current or constant-power load based on the manufacturer’s rating of the battery for the selected test length. See 7.3 for discussion on determining the discharge rate for capacity tests.
In the previous version of this standard, the discharge rate for the time-adjusted method was adjusted for temperature prior to conducting the test. This previous method of temperature compensation is acceptable. In this revision, the time-adjusted method is revised to apply the temperature correction to the capacity cal- culation after completion of the test. Users may transition to this new method at an appropriate time, e.g., at battery replacement.
The discharge rate for service tests is discussed in 7.5.
Discharge rate determination for modified performance tests is discussed in Annex I.
7.3 Capacity test methods
There are two methods for battery capacity testing: rate-adjusted and time-adjusted. Battery capacities deter- mined by the rate-adjusted method are correct for all test durations. However, this method is more difficult to apply than the time-adjusted method. For tests greater than 1 hour, the time-adjusted method in 7.3.1 is acceptable. The rate-adjusted method in 7.3.2 is used for test durations less than 1 hour. For tests of 1 hour duration, either method can be used. Once a test method is chosen, all subsequent tests should use the same method.
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