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

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

This Technical Specification proposes simple, cheap, comparative tests in order to discriminate easily, in a panel of automotive flooded lead-acid batteries the most acceptable
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.

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

General Information

• Status: Published
• Public Enquiry End Date: 31-Dec-2006
• Publication Date: 16-Sep-2008
• ICS: 27.190 - Biological sources and alternative sources of energy
• ICS: 29.220.20 - Acid secondary cells and batteries
• Technical Committee: PVS - Solar photovoltaic energy systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 16-Sep-2008
• Due Date: 21-Nov-2008
• Completion Date: 17-Sep-2008
• Ref Project: IEC/TS 62257-8-1 - Recommendations for small renewable energy and hybrid systems for rural electrification - Part 8-1: Selection of batteries and battery management systems for stand-alone electrification systems - Specific case of automotive flooded lead-acid batteries available in developing countries

Standards Content (sample)

SLOVENSKI STANDARD
SIST-TS IEC/TS 62257-8-1:2008
01-marec-2008
3ULSRURþLOD]DVLVWHPHPDOLKREQRYOMLYLKYLURYHQHUJLMHLQKLEULGQHVLVWHPH]D

HOHNWULILNDFLMRSRGHåHOMDGHO,]ELUDDNXPXODWRUMHYLQVLVWHPRYXSUDYOMDQMD

DNXPXODWRUMHY]DVDPRVWRMQHVLVWHPHHOHNWULILNDFLMH3RVHEQLSULPHU]D
DYWRPRELOVNHPRNUHVYLQþHQRNLVOLQVNHDNXPXODWRUMHNLVRQDYROMRYGHåHODKY
UD]YRMX

Recommendations for small renewable energy and hybrid systems for rural electrification

- Part 8-1: Selection of batteries and battery management systems for stand-alone

electrification systems - Specific case of automotive flooded lead-acid batteries available

in developing countries
Ta slovenski standard je istoveten z: IEC/TS 62257-8-1
ICS:
27.190 Biološki viri in drugi Biological sources and
alternativni viri energije alternative sources of energy
29.220.20 .LVOLQVNLVHNXQGDUQLþOHQLLQ Acid secondary cells and
EDWHULMH batteries
SIST-TS IEC/TS 62257-8-1:2008 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS IEC/TS 62257-8-1:2008
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SIST-TS IEC/TS 62257-8-1:2008
TECHNICAL IEC
SPECIFICATION TS 62257-8-1
First edition
2007-06
Recommendations for small renewable energy
and hybrid systems for rural electrification –
Part 8-1:
Selection of batteries and battery management
systems for stand-alone electrification systems –
Specific case of automotive flooded lead-acid
batteries available in developing countries
PRICE CODE
Commission Electrotechnique Internationale T
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
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SIST-TS IEC/TS 62257-8-1:2008
– 2 – TS 62257-8-1 © IEC:2007(E)
CONTENTS

FOREWORD...........................................................................................................................3

INTRODUCTION.....................................................................................................................5

1 Scope...............................................................................................................................6

2 Normative references .......................................................................................................6

3 Terms and definitions .......................................................................................................6

4 Batteries and battery management system selection ........................................................9

4.1 Batteries technical characteristics ...........................................................................9

4.1.1 Battery cases ..............................................................................................9

4.1.2 Battery terminals .........................................................................................9

4.1.3 Electrolyte ...................................................................................................9

4.2 Comparative tests .................................................................................................10

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 ....................................................15

4.2.4 Test 3: Battery storability test ....................................................................17

5 Documentation ...............................................................................................................18

6 Installation rules .............................................................................................................19

6.1 Packing and shipping ............................................................................................19

6.2 Environment ..........................................................................................................19

6.3 Battery accommodation, housing...........................................................................20

6.3.1 Provision against electrolyte hazard ..........................................................20

6.3.2 Prevention of short circuits and protection from other effects of

electric current ..........................................................................................21

6.3.3 Battery enclosures.....................................................................................21

6.4 Final inspection .....................................................................................................22

6.5 Safety ...................................................................................................................22

6.5.1 Safety provisions .......................................................................................22

6.5.2 Safety Information .....................................................................................22

6.6 Administrative formalities ......................................................................................23

6.7 Recycling ..............................................................................................................23

Figure 1 – Test 1 phases ......................................................................................................11

Figure 2 – Phase A battery endurance test ...........................................................................12

Figure 3 – Phase B battery endurance test ...........................................................................13

Figure 4 – Test 2 phases ......................................................................................................15

Figure 5 – Phase C battery-BMS endurance test...................................................................16

Figure 6 – Test 3 phases ......................................................................................................17

Figure 7 – Phase D storability test ........................................................................................18

Figure 8 – Marking for spillage prevention ............................................................................19

Table 1 – Testing procedure .................................................................................................10

Table 2 – Evaluation of charge and discharge current (I ).................................................10

test

Table 3 – Voltage regulation variation with temperature (examples)......................................11

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SIST-TS IEC/TS 62257-8-1:2008
TS 62257-8-1 © IEC:2007(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY AND
HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –
Part 8-1: Selection of batteries and battery 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

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any

equipment declared to be in conformity with an IEC Publication.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the 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 IEC technical

committee 82: Solar photovoltaic energy systems.
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SIST-TS IEC/TS 62257-8-1:2008
– 4 – TS 62257-8-1 © IEC:2007(E)

This document is based on IEC/PAS 62111 (1999); it cancels and replaces the relevant parts

of IEC/PAS 62111.
This part of IEC 62257 is to be used in conjunction with the IEC 62257 series.

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
82/457/DTS 82/476/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 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.
A bilingual version of this publication may be issued at a later date.
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SIST-TS IEC/TS 62257-8-1:2008
TS 62257-8-1 © IEC:2007(E) – 5 –
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 do not

deal with clean mechanisms developments at this time (CO emission, carbon credit, etc.).

Further 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 IEC 61427.

Nevertheless in many situations, it is a fact that most of the rural electrification projects are

implemented using locally made 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 best service

as close as possible to the requirement of the General Specification as a storage application

for small PV individual electrification systems (see IEC 62257-2) in an economically viable

way.

The purpose of Part 8-1 of 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 in the IEC 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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SIST-TS IEC/TS 62257-8-1:2008
– 6 – TS 62257-8-1 © IEC:2007(E)
RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY AND
HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –
Part 8-1: Selection of batteries and battery management
systems for stand-alone electrification systems –
Specific case of automotive flooded lead-acid batteries
available in developing countries
1 Scope

This Technical Specification proposes simple, cheap, comparative tests in order to

discriminate easily, in a panel of automotive flooded lead-acid batteries the most acceptable

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 60050-482, International Electrotechnical Vocabulary (IEV) – Part 482: Primary and

secondary cells and batteries

IEC 61427, Secondary cells and batteries for photovoltaic energy systems (PVES) – General

requirements and methods of test

IEC 62257 (all parts), Recommendations for small renewable energy and hybrid systems for

rural electrification
3 Terms and definitions

For the purposes of this document, the terms and definitions for secondary cells and batteries

given in IEC 60050-482 and the following apply.
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SIST-TS IEC/TS 62257-8-1:2008
TS 62257-8-1 © IEC:2007(E) – 7 –
3.1
electrochemical cell or battery

electrochemical system capable of storing in chemical form the electric energy received and

which can give it back by conversion
3.2
secondary cell
cell which is designed to be electrically recharged
NOTE The recharge is accomplished by way of a reversible chemical reaction.
[IEV 482-01-03]
3.3
storage battery (secondary battery)

two or more secondary cells connected together and used as a source of electric energy

3.4
lead-acid battery

storage battery in which the electrodes are made mainly from lead and the electrolyte is a

sulphuric acid solution
3.5
terminal (pole)

conductive part provided for the connection of a cell or battery to external conductors

3.6
density
commonly considered as the volumic mass, in kg / dm

NOTE Density is also defined as a dimensionless magnitude expressing the ratio of the electrolyte mass to the

water mass occupying the same volume at 4°C.
3.7
electrolyte

liquid or solid substance containing mobile ions which render it ionically conductive

NOTE The electrolyte may be liquid, solid or a gel.
[IEV 482-02-29]
3.8
dry charged battery

state of delivery of some types of secondary battery where the cells contain no electrolyte and

the plates are dry and in a charged state
[IEV 482-05-30]
3.9
self-discharge

phenomenon by which a cell or battery loses energy in other ways than by discharge into and

external circuit
[IEV 482-03-27]
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)
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SIST-TS IEC/TS 62257-8-1:2008
– 8 – TS 62257-8-1 © IEC:2007(E)
3.11
nominal capacity

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).
3.12
rated capacity (of a cell or a battery)

quantity of electricity, declared by the manufacturer, which a cell or a battery can deliver

under specified conditions after a full charge

NOTE 1 The rated capacity shown on the battery label is given for a discharge period which depends on the

technology used in the battery.

NOTE 2 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

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
electric current at which a secondary cell or battery is charged

NOTE The charge rate is expressed as the reference current I = C /n where C is the rated capacity declared by

t r r

the manufacturer and n is the time base in hours for which the rated capacity is declared.

[IEV 482-05-45]
3.15
ambient temperature
temperature of the medium in the immediate vicinity of a battery
3.16
gassing of a cell

evolution of a gas resulting from electrolysis of the water in the electrolyte of a cell

[IEV 482-05-51]
3.17
constant current charge

charge during which the electric current is maintained at a constant value regardless of the

battery voltage or temperature
[IEV 482-05-38]
3.18
initial charge

commissioning charge given to a new battery to bring it to the fully charged state

3.19
cycling (of a cell or battery)

set of operations that is carried out on a secondary cell or battery and is repeated regularly in

the same sequence

NOTE In a secondary battery these operations may consist of a sequence of a discharge followed by a charge of

a charge followed by a discharge under specified conditions. This sequence may include rest periods.

[IEV 482-05-28]
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SIST-TS IEC/TS 62257-8-1:2008
TS 62257-8-1 © IEC:2007(E) – 9 –
3.20
commissioning
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 Battery technical characteristics
4.1.1 Battery cases

Battery cases shall be made of suitable materials capable of withstanding impacts and shocks

and resistant to acid.
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 sulphuric acid for storage

batteries. It shall be colorless, odorless and free of all insoluble material deposits. As there is

no standard for such an electrolyte, impurity levels shall follow the battery manufacturer

requirements.
The electrolyte level checking interval varies depending on:
• the type of battery;
• the temperature;
• the use;
• the regulation algorithms of the charge controller;
• the battery age;
• the quality of distilled water;
• the PV resource.

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 cm (1 g) H O requires 3 Ah
An estimation of water consumption of a battery is given by

Battery H2O (g) consumption = (X Ah charged – Y Ah discharged) × number of cells in battery / 3.

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SIST-TS IEC/TS 62257-8-1:2008
– 10 – TS 62257-8-1 © IEC:2007(E)
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 4.2.3
See 4.2.2 Test 3: in parallel to test 2, the selected batteries are
subjected to a storability test
See 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 proposed test uses a C I . The C capacity of any battery may be obtained from its

10 test 10
manufacturer.
If not, Table 2 gives an assessment of the C I value for a 100 Ah C battery.
10 test 20
Table 2 – Evaluation of charge and discharge current (I )
test
Nominal Evaluation of Value of I
test
C capacity C capacity
(C × 0,1)
20 10
(Ah) (Ah)
(A)
100 87 8,7

For another nominal capacity, I varies proportionally to the nominal capacity and is

test
intended to be equivalent to a nominal C value.
4.2.2 Test 1: Battery endurance test
4.2.2.1 General

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 performs 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.
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SIST-TS IEC/TS 62257-8-1:2008
TS 62257-8-1 © IEC:2007(E) – 11 –

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 12 V 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 14,51 V
−0,021 V/°C × [15 °C – 20 °C] = +0,11 V
20 °C 14,40 V
35 °C 14,09 V
−0,021 V/°C × [35 °C – 20 °C] = −0,31 V
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 h charge and 12 h 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 A
PHASE B
5 cycles 5 cycles
5 cycles
Repeat 9 times
IEC 1056/07
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 4.2.2.2.2).
Phase B does not include this additional charge (see 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.
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SIST-TS IEC/TS 62257-8-1:2008
– 12 – TS 62257-8-1 © IEC:2007(E)

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 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 in 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.
START Phase A
STOP discharge on
voltage threshold
t = 0
End
Phase A Discharge battery Wait until
t = 12 hours
at I
test
Repeat 5 times the cycle
Wait until
t = 12 hours
t = about 10 hours
START
charge
Additional charge battery
t = 0
Charge battery
at I
test
at I with voltage
test
without voltage
limitation
limitation
End of additional
charge period
IEC 1057/07
Figure 2 – Phase A battery endurance test
4.2.2.2.2.2 Operating procedure
• Discharge the battery at I to 10,8 V (± 0,1 V).
test

• Wait until 12 h from the beginning of the discharge before starting the charge.

• Charge with an initial current equal to I during 10 h with a voltage limitation

...

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

---------------------- Page: 1 ----------------------
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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62257-8-1 © IEC:200X - 2 - 82/457/CD
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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62257-8-1 © IEC:200X - 3 - 82/457/CD
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

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence between any

IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment

declared to be in conformity with an IEC Publication.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members

of its technical committees and IEC National Committees for any personal injury, property damage or other damage of

any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the

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

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.

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

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
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

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.

For another nominal capacity, I varies proportionally to the nominal capacity and is intended to be

test
equivalent to a nominal C value.
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
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
...