ISO/DIS 7176-25

Wheelchairs

Fauteuils roulants

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD ISO/DIS 7176-25
ISO/TC 173/SC 1 Secretariat: SIS
Voting begins on: Voting terminates on:
2004-11-10 2005-04-11

INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION

Wheelchairs —
Part 25:
Requirements and test methods for batteries and their chargers
for electrically powered wheelchairs and motorized scooters
Fauteuils roulants —

Partie 25: Exigences et méthodes d'essai des batteries et leurs chargeurs pour les fauteuils roulants

électriques et scooters motorisés
ICS 11.180.10

In accordance with the provisions of Council Resolution 15/1993 this document is circulated in

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Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué

en version anglaise seulement.

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ISO Central Secretariat work of editing and text composition will be undertaken at publication

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Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du

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Secrétariat central de l'ISO au stade de publication.

THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE

REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.

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INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO

WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
© International Organization for Standardization, 2004
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ISO/DIS 7176-25
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ISO/DIS 7176-25
Contents

Foreword.....................................................................................................................................................................iv

Introduction................................................................................................................................................................vi

1 Scope..............................................................................................................................................................1

2 Normative references....................................................................................................................................1

3 Terms, definitions and symbols...................................................................................................................2

4 Apparatus .......................................................................................................................................................3

5 Requirements.................................................................................................................................................6

6 Preparation for charger tests .....................................................................................................................10

7 Test methods ...............................................................................................................................................11

8 Marking.........................................................................................................................................................15

9 Pre-sale information....................................................................................................................................16

10 User manual .................................................................................................................................................17

11 Test reports ..................................................................................................................................................18

12 Disclosure....................................................................................................................................................20

Annex A (informative) Guidance on charging connector .....................................................................................21

Annex B (informative) Guidance on battery temperature sensing.......................................................................22

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ISO/DIS 7176-25
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO

member bodies). The work of preparing International Standards is normally carried out through ISO technical

committees. Each member body interested in a subject for which a technical committee has been established has

the right to be represented on that committee. International organizations, governmental and non-governmental, in

liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical

Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards adopted

by the technical committees are circulated to the member bodies for voting. Publication as an International

Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.

ISO shall not be held responsible for identifying any or all such patent rights.

ISO 7176-25 was prepared by Technical Committee ISO/TC 173, Technical systems and aids for disabled or

handicapped persons, Subcommittee SC 1, Wheelchairs.
ISO 7176 consists of the following parts, under the general title Wheelchairs:
 Part 1: Determination of static stability
 Part 2: Determination of dynamic stability of electric wheelchairs
 Part 3: Determination of effectiveness of brakes

 Part 4: Energy consumption of electric wheelchairs and scooters for determination of theoretical distance

range
 Part 5: Determination of overall dimensions, mass and turning space

 Part 6: Determination of maximum speed, acceleration and deceleration of electric wheelchairs

 Part 7: Measurement of seating and wheel dimensions
 Part 8: Requirements and test methods for static, impact and fatigue strengths
 Part 9: Climatic tests for electric wheelchairs
 Part 10: Determination of obstacle-climbing ability of electric wheelchairs
 Part 11: Test dummies
 Part 13: Determination of coefficient of friction of test surfaces

 Part 14: Power and control systems for electric wheelchairs — Requirements and test methods

 Part 15: Requirements for information disclosure, documentation and labelling

 Part 16: Resistance to ignition of upholstered parts — Requirements and test methods

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ISO/DIS 7176-25
 Part 19: Wheeled mobility devices for use in motor vehicles

 Part 21: Requirements and test methods for electromagnetic compatibility of electrically powered wheelchairs

and motorized scooters
 Part 22: Set-up procedures

 Part 23: Requirements and test methods for attendant-operated stair-climbing devices

 Part 25: Batteries and chargers for electrically powered wheelchairs and motorized scooters — Requirements

and test methods
 Part 26: Vocabulary.

A Technical Report (ISO/TR 13570:2001, Guidelines for the application of the ISO 7176 series on wheelchairs) is

also available giving a simplified explanation of these parts of ISO 71766.
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ISO/DIS 7176-25
Introduction

The reliability and performance of an electrically powered wheelchair or scooter depend on the performance and

reliability of the battery set, which depend in turn on the performance and reliability of the battery charger, and on

the correct operation of the charger by the user. Batteries and chargers are used in a wide range of conditions.

Since batteries are often costly, it is important to avoid premature failure by maintaining a correct charging regime

under such operating conditions.

It is important that wheelchair manufacturers, and battery and charger manufacturers who intend their products to

be used with wheelchairs, ensure that risks to disabled or elderly users and carers arising from their equipment are

eliminated or reduced as far as is practicable. Such risks can include those arising from high surface temperatures,

incompatibility, misuse of connectors and extended periods of charging.

Battery chargers can be divided into three types: off-board, carry-on and on-board. Operating, transport and

storage situations can differ for these types, so it is appropriate to apply different requirements to them. In

particular, on-board chargers are treated as wheelchair components, while carry-on chargers and off-board

chargers are not.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 7176-25
Wheelchairs —
Part 25:
Requirements and test methods for batteries and their chargers
for electrically powered wheelchairs and motorized scooters

WARNING This International Standard calls for the use of procedures that may be hazardous to health if

adequate precautions are not taken. It refers only to technical suitability and does not absolve the manufacturer or

test house from legal obligations relating to health and safety.
1 Scope

This International Standard specifies requirements and test methods for lead-acid batteries and battery chargers

for electrically powered wheelchairs and scooters, having a maximum speed not greater than 15 km/h, intended for

use by people with disabilities. It is not applicable to battery types other than lead-acid. The requirements for

chargers are applicable to those with a rated input voltage not greater than 250 V a.c. intended for charging lead-

acid batteries with a nominal voltage not greater than 36 V.

This International Standard specifies test methods that can help assess compatibility between batteries and

chargers.
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.

ISO 7176-8, Wheelchairs — Part 8: Requirements and test methods for static, impact and fatigue strengths

ISO 7176-9, Wheelchairs — Part 9: Climatic tests for electric wheelchairs

ISO 7176-15, Wheelchairs — Part 15: Requirements for information disclosure, documentation and labelling

ISO 7176-19, Wheelchairs — Part 19: Wheeled mobility devices for use in motor vehicles

ISO 7176-21, Wheelchairs — Part 21: Requirements and test methods for electromagnetic compatibility of

electrically powered wheelchairs and motorized scooters

IEC 60335-1, Household and similar electrical appliances — Safety — Part 1: General requirements

IEC 60335-2-29, Household and similar electrical appliances — Safety — Part 2-29: Particular requirements for

battery chargers
IEC 60529, Degrees of protection provided by enclosures (IP Code)

IEC 61056-1, General purpose lead-acid batteries (valve-regulated types) — Part 1: General requirements,

functional characteristics — Methods of test
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ISO/DIS 7176-25
3 Terms, definitions and symbols
For the purposes of this document, the following terms and definitions apply.
3.1
battery

one or more cells fitted with devices necessary for use, for example case, terminals, marking and protective

devices
[IEV 482-01-04]
3.2
lead acid battery

secondary battery with an aqueous electrolyte based on dilute sulphuric acid, a positive electrode of lead dioxide

and a negative electrode of lead
NOTE Lead dioxide lead batteries are often called accumulators (deprecated).
[IEV 482-05-01]
3.3
nominal voltage

suitable approximate value of voltage used to designate or identify the voltage of the battery

NOTE 1 Adapted from IEV 482-03-31.

NOTE 2 For lead acid batteries the nominal voltage is usually two volts multiplied by the number of cells.

3.4
free ventilated battery
wet battery

lead acid battery that has a liquid electrolyte free to move within cells that are vented at atmospheric pressure

3.5
valve regulated lead acid battery
VRLA (abbreviation)
sealed lead acid battery
valve regulated sealed battery

lead acid battery in which cells are closed but have a valve that allows the escape of gas if the internal pressure

exceeds a predetermined value
NOTE 1 The battery cannot normally receive additions to the electrolyte.
NOTE 2 Adapted from IEV 482-05-15.

NOTE 3 Valve regulated lead acid batteries often have a construction similar to that of free ventilated batteries. Common

types of valve regulated batteries are gelled electrolyte batteries and absorbent glass mat (AGM) batteries.

3.6
gelled electrolyte battery
gel battery
lead acid battery in which the electrolyte is a thixotropic gel

NOTE This type of battery is resistant to leakage within orientations specified by the battery manufacturer.

3.7
absorbent glass mat (AGM) battery

lead acid battery in which the electrolyte is absorbed into separators made of glass fibres

NOTE This type of battery is resistant to leakage within orientations specified by the battery manufacturer.

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ISO/DIS 7176-25
3.8
off-board battery charger
free-standing, self-contained battery charger separate from a wheelchair
3.9
carry-on battery charger
off-board battery charger intended for transportation on a wheelchair
3.10
on-board battery charger

battery charger that is built into a wheelchair and cannot be removed without use of tools

3.11
rated input voltage
supply voltage assigned to the battery charger by its manufacturer
3.12
equalising current

extended charging current intended to ensure an equal state of charge of all cells in the battery

NOTE Equalising the charge of the cells in a battery can significantly extend battery life.

3.13
test battery

battery of the type, rated capacity and nominal voltage for which the battery charger is specified

3.14
safety hazard

potentially detrimental effect on the user, other persons, animals, or the surroundings, arising directly from the

battery charger or battery
NOTE Adapted from IEC 60601-1.
3.15

rated capacity of the battery for a discharge time of 5 h, expressed in ampere hours

3.16

rated capacity of the battery for a discharge time of 20 h, expressed in ampere hours

3.17
the electric current C / 5 h, expressed in amperes
3.18
the electric current C / 20 h, expressed in amperes
4 Apparatus

The circuit for testing battery chargers specified in IEC 60335-2-29 is not to be used, since inconsistent

measurements will result. The circuitry specified in this standard is intended to improve consistency.

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ISO/DIS 7176-25

4.1 Means for discharging a battery, that can be adjusted to draw a specified current to an accuracy of 2 %. It

shall include

- a means to end the discharge after a specified time has elapsed, with an accuracy of 1 min,

- a means to prevent the battery being discharged below the minimum voltage specified by the battery

manufacturer, and
- a means to measure the capacity drawn from the battery to an accuracy of 3 %.

EXAMPLE A circuit diagram for a means to discharge a battery at a specified current is shown in Figure 1.

Key
I discharge current

NOTE This example is intended for use with a battery that has a nominal voltage of 24 V. It is suitable for discharge currents

not greater than 15 A. It does not include a means to discontinue discharging or a means to measure the capacity drawn from

the battery.
Figure 1 — Example of a means to discharge a battery at a specified current
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NOTE This example is intended for use with a battery that has a nominal voltage of 24 V. It is suitable for charging currents

not greater than 15 A.
Figure 2 — Example of a shunt voltage regulator

4.2 Shunt voltage regulator, that can be adjusted to conduct at a specified voltage (usually(2,1× n) V, where n

is the number of cells in the battery) and that is capable of dissipating the maximum power that can be supplied by

the battery charger. In use, the shunt voltage regulator is connected in parallel with a battery. The regulator shall

prevent the battery terminal voltage from exceeding (2,2× n) V at the maximum charging current.

NOTE Some chargers will not commence charging if their load voltage is less than a minimum value.

EXAMPLE A circuit diagram for a shunt voltage regulator is shown in Figure 2.

4.3 Means to measure surface temperature, as specified in IEC 60335-1 for measuring the temperature rise of

windings.

4.4 Means to measure and record the arithmetic mean current of a battery, to an accuracy of 2 % of the

measurement, consisting of a current transducer, such as a suitably rated resistor, and a recording means, such as

a chart recorder or storage oscilloscope. The recording means shall be capable of recording over a period of 25 h

with a sampling period not longer than 1 min. Avoid any measurement errors due to changes of gain or offset

during the recording period, and due to noise and aliasing.

The voltage drop across the current transducer shall not exceed 0,2 % of the nominal battery voltage.

4.5 Means to measure the arithmetic mean current delivered to a battery, to an accuracy of 5 % of the

measurement. Suitable means include a current transducer, such as a suitably rated resistor, and an indicating

means, such as an oscilloscope.

The voltage drop across the current transducer shall not exceed 0,2 % of the nominal battery voltage.

4.6 Means to alter the a.c. supply voltage to a battery charger, normally consisting of a tapped or

continuously adjustable variable transformer. The means should not cause the peak supply voltage of the charger

when fully loaded to differ by more than 2 % from the peak supply voltage of the charger when not loaded.

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5 Requirements
5.1 Requirements for battery chargers

5.1.1 Battery chargers shall meet the requirements of IEC 60335-1 for class II appliances.

5.1.2 Battery chargers shall meet the requirements of IEC 60335-2-29.

5.1.3 On-board battery chargers, when set up as specified in Clause 6, shall meet the charging requirements of

ISO 7176-21 that apply to wheelchairs with built-in battery chargers.

Where no requirements that apply to wheelchairs with off-board battery chargers or carry-on battery chargers are

included in the current edition of ISO 7176-21, off-board battery chargers and carry-on battery chargers, when set

up as specified in Clause 6, shall meet the charging requirements of ISO 7176-21 that apply to wheelchairs with

built-in battery chargers.

Where requirements that apply to wheelchairs with off-board battery chargers or carry-on battery chargers are

included in the current edition of ISO 7176-21, off-board battery chargers and carry-on battery chargers, when set

up as specified in Clause 6, shall meet the charging requirements of ISO 7176-21 that apply to wheelchairs with

off-board battery chargers or carry-on battery chargers.

NOTE 1 These transitional requirements have been included because the current edition of ISO 7176-21 does not apply to

wheelchairs with off-board battery chargers or carry-on battery chargers. It is anticipated that the next edition of ISO 7176-21

will include requirements for such wheelchairs.

NOTE 2 Some countries may have requirements for electromagnetic compatibility in addition to those specified in ISO 7176-

21.

5.1.4 If off-board battery chargers are intended for use in dry indoor areas only, they shall provide a degree of

protection of IPX1 when tested as specified in IEC 60529, and meet the leakage current and electric strength

requirements specified in IEC 60335-1 for class II appliances after the test.

NOTE This standard specifies additional marking requirements for such chargers (see Clause 8).

Otherwise, off-board chargers shall provide the degree of protection specified in this standard for carry-on

chargers.

5.1.5 Carry-on battery chargers and on-board battery chargers, when set up as specified in Clause 6, shall

provide a degree of protection of IPX4 when tested as specified in IEC 60529, and meet the leakage current and

electric strength requirements specified in IEC 60335-1 for class II appliances after the test.

5.1.6 Installed on-board battery chargers shall function in accordance with the charger manufacturer’s

specification and shall not give rise to a safety hazard, both during and following testing of the wheelchair as

specified in ISO 7176-9.

5.1.7 When battery chargers are tested in accordance with IEC 60335-1 and 7.12 of this standard

- the temperatures of accessible surfaces and the internal temperatures shall meet the heating requirements of

IEC 60335-1,

- the allowable temperature rise shall be 40 K for metallic enclosures and 60 K for non-metallic enclosures, and

- the allowable temperature rise shall be 30 K for metallic handles and 50 K for non-metallic handles.

5.1.8 Installed on-board battery chargers and carry-on battery chargers shall function in accordance with the

charger manufacturer’s specification and shall not give rise to a safety hazard, both during and following testing of

the wheelchair as specified in ISO 7176-8.

After such testing, installed on-board battery chargers and carry-on battery chargers shall meet the requirements of

IEC 60335-2-29 concerning protection against access to live parts.
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5.1.9 On-board battery chargers shall not be removed from wheelchairs during testing in accordance with ISO

7176-19.

After such testing, on-board battery chargers shall meet the general requirements of IEC 60335-2-29 and the

requirements of IEC 60335-2-29 concerning protection against access to live parts, clearances, creepage

distances and protection against mechanical hazards.

5.1.10 If the output of off-board battery chargers or carry-on battery chargers is carried through a conductive

connection, it shall be a single flexible cord attached to the charger and fitted with a male connector. The r.m.s.

current rating of both the cord and the connector shall exceed the rated d.c. output current of the charger.

Pin numbers shall be clearly marked on the charging connector. The pins shall be assigned as follows:

- pin 1 — battery positive;
- pin 2 — battery negative and common for temperature sensing;
- pin 3 — inhibit.
Other pins may be connected at the charger manufacturer’s discretion.
NOTE 1 The pin numbers are those declared by the connector manufacturer.

NOTE 2 Pin 3 is commonly connected to battery negative for off-board chargers and carry-on chargers. Driving is prevented

while the wheelchair controller senses the presence of the connection.

The conductors in the output cable shall have thermoplastic insulation with a thickness not less than 0,8 mm and a

temperature rating not less than 80 °C.

NOTE 3 Annex B gives guidance on battery temperature sensing, which can give an improvement in the safety of charging

and, in some cases, the quality of charging.

5.1.11 All cords attached to off-board battery chargers and carry-on battery chargers shall meet the cord

anchorage requirements of IEC 60335-1.

5.1.12 If battery chargers are intended to be suitable for charging batteries with more than one nominal voltage

and the method by which the output voltage is selected is manual, it shall not be possible to change the output

voltage setting without a tool, key entry combination or similar means of restricting access. If the means of

restricting access is other than a tool, it shall not consist of operations that are performed in normal use of the

charger.

Battery chargers shall not provide automatic output voltage selection based on the voltage of the battery.

5.1.13 If battery chargers are intended to be suitable for charging more than one type of battery, the selected

battery type shall be clearly discernible. It shall not be possible to change the battery type setting without a tool, key

entry combination or similar means of restricting access. If the means of restricting access is other than a tool, it

shall not consist of operations that are performed in normal use of the charger.

This sub-clause does not apply to chargers that have a means for automatically detecting the battery type.

5.1.14 Battery chargers shall provide indications of the following conditions:

- the charger is correctly connected to a battery and/or normal charging is in progress;

- charging is complete;
- a fault has occurred.
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ISO/DIS 7176-25

Battery chargers shall provide an indicator light that clearly indicates to users that the charger is connected to the

supply mains and switched on.

Colours for indicators should be as shown in Table 1. Red indicator lights shall be used exclusively to indicate a

warning of danger and/or the need for urgent action. Textual displays may be any colour.

Clearly discernible markings shall be provided adjacent to indicators to identify their function. Markings used for this

purpose shall, wherever practicable, be comprehensible without a knowledge of languages or national standards.

Table 1 — Recommended colours for indicators
Colour Meaning Example
Green Ready for action Charging complete
Yellow Caution or attention required Charging commenced
Red Danger and/or need for urgent action Fault present — disconnect charger
Any other colour Meaning other than that of red or State of partial charge
yellow
5.1.15 When battery chargers are tested in accordance with 7.10

- the steady-state current that flows to discharge the battery shall not be greater than 100 mA,

- there shall be no damage to the battery charger, and

- following resetting and/or replacement of any circuit protection devices the battery charger shall operate as

specified by the charger manufacturer.

5.1.16 Battery chargers shall operate without the need for intervention or supervision apart from connecting and

switching on at the start of charging and switching off and disconnecting at the end of charging.

5.1.17 Battery chargers shall be protected against overload of transformers and associated circuits in accordance

with IEC 60335-2-29.
Chargers may be protected against overload by
- the inherent impedance of transformer windings,
- fuses,
- automatic controls,
- thermal cut-outs, or

- similar devices incorporated into the charger, if they are accessible only with the use of a tool.

5.1.18 The electrical resistance between any part of the enclosure of a battery charger and any output conductor

shall not be less than 10 kΩ.
...