SIST-TS IEC/TS 62257-8-1:2008

SLOVENSKI oSIST-TS IEC/TS 62257-8-
1:2006

PREDSTANDARD
december 2006
Priporočila za sisteme malih obnovljivih virov energije in hibridne sisteme za
elektrifikacijo podeželja – 8-1. del: Izbira akumulatorjev in sistemov
upravljanja akumulatorjev za samostojne sisteme elektrifikacije – Posebni
primer za avtomobilske mokre svinčeno-kislinske akumulatorje, ki so na voljo
v deželah v razvoju
Recommendations for small renewable energy and hybrid systems for rural
electrification - Part 8-1: Selection of batteries and batteries management systems
for stand-alone electrification systems - Specific case of automotive flooded lead-
acid batteries available in developing countries
ICS 27.190; 29.220.20 Referenčna številka
oSIST-TS IEC/TS 62257-8-1:2006(en)
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

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82/457/DTS
DRAFT TECHNICAL SPECIFICATION
Project number IEC 62257-8-1 TS Ed.1
IEC/TC or SC Secretariat
TC 82 U.S.A
Distributed on Voting terminates on
2006-10-06 2007-01-12

Also of interest to the following committees Supersedes document
TC 21, SC 21A, TC 88, TC 105 82/427/CD - 82/456/CC
Functions concerned

Safety EMC Environment Quality assurance
THIS DOCUMENT IS STILL UNDER STUDY AND SUBJECT TO CHANGE. IT

SHOULD NOT BE USED FOR REFERENCE PURPOSES.
RECIPIENTS OF THIS DOCUMENT ARE INVITED TO SUBMIT, WITH THEIR
COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF
WHICH THEY ARE AWARE AND TO PROVIDE SUPPORTING
DOCUMENTATION.

Title:
IEC 62257-8-1 TS Ed.1: Recommendations for small renewable energy and hybrid
systems for rural electrification – Part 8-1 : Selection of batteries and batteries
management systems for stand-alone electrification systems - Specific case of
automotive flooded lead-acid batteries available in developing countries


Introductory note:
Rural electrification is one of the predominant policy actions designed to increase the well being of rural populations
together with improved healthcare, education, personal advancement and economical development.

The purpose of Part 8-1 of the IEC 62257 is to specify the general requirements for batteries and batteries management
systems used in stand-alone electrification systems. This document and the others of the 62257 series are only guidance
and so cannot be international standards. Additionally their subject is still under technical development and so they shall
be published as Technical Specifications.


Note: The IEC 62257 series of Technical Specifications is based on IEC/PAS 62111 (1999-07) and is developed in
accordance with the PAS procedure.






Copyright © 2006 International Electrotechnical Commission, IEC. All rights reserved. It is
permitted to download this electronic file, to make a copy and to print out the content for the sole
purpose of preparing National Committee positions. You may not copy or "mirror" the file or
printed version of the document, or any part of it, for any other purpose without permission in
writing from IEC.
FORM CD (IEC) 2002-08-08

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CONTENTS
FOREWORD . 3
INTRODUCTION .5
1 Scope . 6
2 Normative references. 6
3 Terms and definitions. 7
4 Batteries and battery management system selection . 8
4.1 Batteries technical characteristics. 8
4.1.1 Battery cases . 8
4.1.2 Battery Terminals. 9
4.1.3 Electrolyte. 9
4.2 Comparative tests . 9
4.2.1 Evaluation of the charge and discharge current for testing (I ) . 10
test
4.2.2 Test 1: Battery endurance test . 10
4.2.3 Test 2: Endurance test for battery+BMS. 14
4.2.4 Test 3 : Battery storability test. 16
5 Documentation. 17
6 Installation rules. 18
6.1 Packing and shipping. 18
6.2 Environment . 18
6.3 Battery accommodation, housing . 19
6.3.1 Provision against electrolyte hazard . 19
6.3.2 Prevention of short circuits and protection from other effects of electric
current . 20
6.3.3 Specific requirements for separate battery roomsError! Bookmark not defined.
6.3.4 Battery enclosures . 20
6.4 Final inspection. 21
6.5 Safety . 21
6.5.1 Safety provisions. 21
6.5.2 Safety Information. 21
6.6 Administrative formalities . 22
6.7 Recycling. 22

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

Recommendations for small renewable energy and hybrid systems for
rural electrification –
Part 8-1 : Selection of batteries and batteries management systems for stand-
alone electrification systems - Specific case of automotive flooded lead-acid
batteries available in developing countries

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all
national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-
operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition
to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly
Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in
this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also
participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in
accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all interested
IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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6) All users should ensure that they have the latest edition of this publication.
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publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. In exceptional
circumstances, a technical committee may propose the publication of a technical specification when
• the required support cannot be obtained for the publication of an International Standard, despite
repeated efforts, or
• The subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide whether
they can be transformed into International Standards.
IEC 62257-8-1, which is a technical specification, has been prepared by of IEC technical committee
82: Solar photovoltaic energy systems.
This document is based on IEC/PAS 62111; it cancels and replaces the relevant parts of IEC/PAS
62111.

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This technical specification is to be used in conjunction with:
IEC 62257-1:Recommendations for small renewable energy and hybrid systems for rural
electrification – Part 1: General introduction to rural electrification
IEC 62257-2:Recommendations for small renewable energy and hybrid systems for rural
electrification – Part 2: From requirements to a range of electrification systems
IEC 62257-3: Recommendations for small renewable energy and hybrid systems for rural
electrification – Part 3: Project development and management
IEC 62257-4: Recommendations for small renewable energy and hybrid systems for rural
electrification – Part 4: System selection and design
IEC 62257-5: Recommendations for small renewable energy and hybrid systems for rural
electrification – Part 5: Safety rules - protection against electrical hazards
IEC 62257-6: Recommendations for small renewable energy and hybrid systems for rural
electrification – Part -6: Acceptance, operation, maintenance and replacement
It is also to be used with future parts of this series as and when they are published.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
82/XX/DTS 82/XX/RVC

Full information on the voting for the approval of this technical specification can be found in the
report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until the
)
1
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.


1)
The National Committees are requested to note that for this publication the maintenance result date is 2010

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INTRODUCTION
The IEC 62257 series of documents intends to provide to different players involved in rural
electrification projects (such as project implementers, project contractors, project supervisors,
installers, etc.) documents for the setting up of renewable energy and hybrid systems with a.c.
voltage below 500 V, d.c. voltage below 750 V and power below 100 kVA.

These documents are recommendations :

• to choose the right system for the right place
• to design the system
• to operate and maintain the system

These documents are focused only on rural electrification concentrating on but not specific to
developing countries. They must not be considered as all inclusive to rural electrification. The
documents try to promote the use of Renewable energies in rural electrification; they don’t deal with
clean mechanisms developments at this time (CO emission, carbon credit, etc.). Further
2
developments in this field could be introduced in future steps.
This consistent set of documents is best considered as a whole with different parts corresponding to
items for safety, sustainability of systems and at the lowest life cycle cost as possible. One of the
main objectives is to provide the minimum sufficient requirements, relevant to the field of
application that is: small renewable energy and hybrid off-grid systems.
For rural electrification project using PV systems, it is recommended to use solar batteries defined
in the International Standard IEC 61427 Ed.2 “Secondary cells and batteries for solar photovoltaic
energy systems – General requirements and methods of test”.
Nevertheless in many situations, due to budget reasons, Project Implementers cannot afford solar
photovoltaic batteries and use cheaper products. The most used and locally made products are
automotive flooded lead–acid batteries, But these products are not designed for photovoltaic
systems application. There is presently no test to discriminate, in a panel of models of such
batteries, which one could provide the required service as a storage application for small PV
individual electrification systems (IES-see 62257 2) in an economically viable way.
The purpose of Part 8-1 of the IEC 62257 is to propose tests for automotive lead acid batteries and
batteries management systems used in small PV Individual Electrification Systems
This document and the others of the 62257 series are only guidance and so cannot be international
standards. Additionally their subject is still under technical development and so they shall be
published as Technical Specifications.
Note: The IEC 62257 series of Technical Specifications is based on IEC/PAS 62111 (1999-07) and is developed in
accordance with the PAS procedure.

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY AND HYBRID
SYSTEMS FOR RURAL ELECTRIFICATION –

Part 8-1 : Selection of batteries and batteries management systems for stand-
alone electrification systems - Specific case of automotive flooded lead-acid
batteries available in developing countries



1 Scope
The document proposes simple, cheap, comparative tests in order to discriminate easily, in a panel
of automotive flooded lead-acid batteries the most appropriate model for PV Individual
Electrification Systems.
It could be particularly useful for Project Implementers to test in laboratories of developing countries,
the capability of locally made car or truck batteries to be used for their project.
Furthermore battery testing specifications usually need too costly and too much sophisticated test
equipment to be applied in developing countries laboratories.
The tests provided in this document allow to assess batteries performances according to the
General Specification of the project (see IEC 62257-2) and batteries associated with their Battery
Management System (BMS) in a short time and with common technical means. They can be
performed locally, as close as possible to the real site operating conditions.
The document provides also regulations and installation conditions to be complied with in order to
ensure the life and proper operation of the installations as well as the safety of people living in
proximity to the installation.
This document is not a type approval standard. It is a technical specification to be used as
guidelines and does not replace any existing IEC standard on batteries.
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of the
referenced document (including any amendments) applies.
IEC 60050-486, International electro technical vocabulary (IEV) – Part 486: Secondary cells and
batteries
IEC 60721-1, Classification of environmental conditions – Part 1: Environmental parameters and
their severities
IEC 61427-Ed2, Secondary cells and batteries for photovoltaic energy systems (PVES)- general
requirements and methods of test
IEC 61340-4-1 Electrostatics - Part 4-1: Standard test methods for specific applications - Electrical
resistance of floor coverings and installed floors

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3 Terms and definitions
For the purpose of this document, the definitions and terms for secondary cells and batteries given
in IEC 60050-486 apply.
3.1
electrochemical cell or battery [IEV 486-01-01]
an electrochemical system capable of storing in chemical form the electric energy received and
which can give it back by conversion
3.2
secondary cell [IEV 486-01-02]
an assembly of electrodes and electrolyte which constitutes the basic unit of a secondary battery
3.3
storage battery (secondary battery) [IEV 486-01-03]
two or more secondary cells connected together and used as a source of electric energy
3.4
lead-acid battery [IEV 486-01-04]
storage battery in which the electrodes are made mainly from lead and the electrolyte is a sulfuric
acid solution.
3.5
terminal (pole) [IEV 486-02-16]
a conductive part provided for the connection of a cell or battery to external conductors.
3.6
density
dimensionless magnitude expressing the ratio of the electrolyte mass to the water mass occupying
the same volume at 4°C
3.7
electrolyte [IEV 486-02-19]
a liquid or solid phase containing mobile ions which render the phase ionically conductive.
3.8
dry charged battery
a secondary battery stored without electrolyte whose plates are dry and in a charged state.
3.9
self discharge [IEV 486-03-27]
loss of chemical energy due to spontaneous reactions within the battery when not connected to an
external circuit
Note 1: This reaction also exists when charging and discharging.
Note 2:The auto discharge current varies with the voltage applied on the terminals of the cells, temperature, age and type
of cells.
3.10
observed battery capacity
quantity of electricity or electrical charge that a battery in high state of charge can deliver under the
proposed test conditions. In practice, battery capacity is expressed in ampere-hours(Ah),
3.11
nominal capacity [IEV 486-03-21]
a suitable approximate quantity of electricity, used to identify the capacity of a cell or a battery.
Note: this value is usually expressed in ampere-hours (Ah),

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3.12
rated capacity (of a cell or a battery) [IEV 486-03-21]
the quantity of electricity, declared by the manufacturer, which a cell or a battery can deliver under
specified conditions after a full charge

NOTE: The rated capacity shown on the battery label is given for a discharge period which depends on the technology
used in the battery:
NOTE : The capacity of a battery is higher when it is discharged slowly. For example, variations are in the order of 10 % to
20 % between a capacity measured over 5 hours and a capacity measured over 100 hours .
3.13
short-circuit current [IEV 486-03-26]
the maximum current given by a battery into a circuit of a very low resistance compared with that of
the battery, under specified conditions.
3.14
charge rate[IEV 486-03-06]
the current at which a battery is charged.
3.15
ambient temperature[IEV 486-03-12]
temperature of the medium in the immediate vicinity of a battery
3.16
gassing [IEV 486-03-24]
the formation of gas produced by electrolysis of the electrolyte
3.17
constant current charge[IEV 486-03-24]
a charge during which the current is maintained at a constant value.
3.18
initial charge
a commissioning charge given to a new battery to bring it to the fully charged state
3.19
cycle [IEV 486-03-28]
a sequence of a discharge followed by a charge or a charge followed by a discharge of a battery
under specified conditions.
3.20
commissioning [IEV 486-03-28]
final checking of installation and operation of a battery on site.
3.21
BMS
battery management system (or battery charge/discharge controller)

4 Batteries and battery management system selection
4.1 Batteries technical characteristics
4.1.1 Battery cases
Batteries cases shall be made of suitable materials capable of withstanding impacts and shocks and
resistant to acid.

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4.1.2 Battery Terminals
Terminals shall be protected against accidental short circuits. Positive and negative polarities shall
be identified.
4.1.3 Electrolyte
The electrolyte for lead acid batteries is prepared from special sulfuric acid for storage batteries. It
shall be colorless, odorless and free of all insoluble material deposits. As there is no standard for
such electrolyte, impurities level shall follow the battery manufacturer requirements.
The electrolyte level checking interval varies depending on:
• the type of battery,
• the temperature,
• the use to which it is put,
• the regulation system used,
• the battery age,
• the quality of distilled water .
The service interval would be determined by the above parameters and electrolyte reservoir size
which is a specification of the specific battery used. Care should be used to ensure that the service
interval is within the capability of the maintenance organization.
The batteries shall be designed in order to be able to check the electrolyte levels and to add
distilled water.
NOTE 1: faradic water consumption for vented batteries:
When a battery reaches its fully state of charge, water electrolysis occurs according to the Faraday’s Law.
Under standard conditions :
3 3
1 Ah decomposes H O into 0,42 dm H + 0,21 dm O
2 2 2
Decomposition of 1 cm3 (1 g) H O requires 3 Ah
2
An estimation of water consumption of a battery is given by :
Battery H O (g) consumption = (X Ah charged - Y Ah discharged)*number of cells in battery / 3
2

NOTE 2: the number of cells for a 12 V lead acid battery is 6

4.2 Comparative tests
The proposed comparative tests are designed to discriminate the most appropriate batteries taking
in consideration the techno economic context of the project.
These comparative tests include a sequence of three tests as indicated in Table 1.
IMPORTANT : All the batteries shall be tested simultaneously in order to ensure that they are tested
in the same conditions (insulation, temperature, etc.).
Table 1 : Testing procedure
 Test 2: the couple battery-BMS is selected
with another endurance test
Test 1: most durable batteries are first
selected with a battery endurance test See clause 4.2.3

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See clause 4.2.2 Test 3: in parallel to test 2, the selected
batteries are subjected to a storability test
See clause 4.2.4

The installation rules for batteries provided in Clause 6 are also applicable to test installations.
4.2.1 Evaluation of the charge and discharge current for testing (I )
test
Automotive lead acid batteries are typically rated at C The I proposed in the following Table 2 is
20. test
based on a nominal C capacity of 100 Ah.
20
For another nominal capacity, I varies proportionally to the nominal capacity and is intended to be
test
equivalent to a nominal C value.
10
Table 2: Evaluation of charge and discharge current (Itest)
Nominal Evaluation of Value of I
test
capacity (Ah) C capacity (C x 0,1)
10 10
100 C 87 Ah 8,7 A
20

4.2.2 Test 1: Battery endurance test
4.2.2.1 Introduction
This test aims to compare the capability of the batteries to maintain their first observed capacity.
NOTE: This test is dedicated to batteries for PV systems. But a battery that perform best in this test is likely to perform
best in other applications (such as wind systems, pico hydro systems) when compared to other batteries of similar types.
For each type of battery, the test is performed by subjecting 3 samples to a 2 phases procedure.
The test is realized at ambient temperature. All the samples shall be tested simultaneously.
The test is proposed for 12V batteries.
For 24 V batteries, voltage thresholds shall be multiplied by 2.
Charge voltage limitations are given for an ambient temperature of 20°C. The rule proposed to
calculate the voltage limitation in accordance with the variation of the temperature is as follows:
For an ambient temperature different from 20°C, voltage limitation shall be set according to :
-21 mV / °C for a 12 V lead-acid bloc. Voltage limitation threshold is calculated according to the
usual average value of the local ambient temperature of the season when the test is performed.
Some examples of the application of this rule are given in Table 3.
Table 3: Voltage regulation variation with temperature (examples)
Ambient Voltage regulation variation / value at 20°C Voltage regulation
temperature
15° C -0,021 V/°C x [15°C-20°C] = + 0,11 V 14,51 V
20°C 14,40 V
35°C -0,021 V/°C x [35°C-20°C] = - 0,31 V 14,09 V

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4.2.2.2 Test 1 procedure
4.2.2.2.1 General
The endurance test simulates the use of a battery in a photovoltaic system. The charge and
discharge are based on one cycle per day, i.e.12 hours charge and 12 hours discharge. This kind of
cycle is as close as possible to the field conditions.
The test is performed as presented in Figure 1.


PHASE A PHASE B PHASE A
5 cycles
5 cycles 5 cycles
Repeat 9 times


Figure 1 : Test 1 phases
Phase A is a discharge/charge cycle including an additional charge ensuring that the battery is on a
high state of charge. (see clause 4.2.2.2.2)
Phase B doesn’t include this additional charge. (see clause 4.2.2.2.3)
The initial phase A is performed to prepare the batteries. This assesses the initial observed
capacity of the batteries and ensures that the test is performed with batteries on a high state of
charge.
The sequence of phase A and phase B intends to reproduce the operating mode of the battery
simulating a sequence of charges and discharges with or without overcharge period.
After the preparation of the battery a series of Phase B + Phase A is performed 9 times (as shown
on Figure 1).
During each discharge, observed capacity is assessed as explained in clause 4.2.2.2.2.4.
After each Phase A an average observed capacity is calculated.
When the complete test 1 process is achieved, 10 values of observed capacity are available.
Interpretation of results is given is the following clause 4.2.2.4.
A curve showing the change in capacity during the complete testing period could be used to
understand differences between different battery models and the variability of performance of
batteries of the same model.
After 90 cycles, this test will show the relative performance of the different batteries being
considered.
4.2.2.2.2 Phase A
4.2.2.2.2.1 General
Phase A cycle is performed 5 times as presented in Figure 2.

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START Phase A
STOP discharge
...