kSIST ISO 21780:2021

Road vehicles - Supply voltage of 48 V - Electrical requirements and tests

This document covers requirements and tests for the electric and electronic components in road vehicles equipped with an electrical system operating at a nominal voltage of 48 V DC.
This includes the following:
— general requirements on 48 V DC electrical systems;
— voltage ranges;
— slow voltage transients and fluctuations (not including EMC).

Véhicules routiers - Tension d'alimentation de 48 V - Exigences électriques et essais

Cestna vozila - Napajalna napetost 48 V - Električne zahteve in preskusi

General Information

• Status: Not Published
• ICS: 43.040.10 - Electrical and electronic equipment
• Technical Committee: EVA - Fuses
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 29-Oct-2021
• Due Date: 17-Dec-2021
• Completion Date: 29-Dec-2021
• Ref Project: ISO 21780:2020 - Road vehicles — Supply voltage of 48 V — Electrical requirements and tests

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 21780
First edition
2020-08
Road vehicles — Supply voltage of
48 V — Electrical requirements and
tests
Véhicules routiers — Tension d'alimentation de 48 V — Exigences
électriques et essais
Reference number
ISO 21780:2020(E)
©
ISO 2020

---------------------- Page: 1 ----------------------
ISO 21780:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 21780:2020(E)

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Functional status . 2
4.1 General . 2
4.2 Functional status 1 (FS1) . 3
4.3 Functional status 2 (FS2) . 3
4.4 Functional status 3 (FS3) . 3
4.5 Functional status 4 (FS4) . 3
4.6 Functional status 5 (FS5) . 3
5 Supply voltage range . 3
6 Functional categories . 5
7 Operating modes . 6
8 General tests conditions . 6
8.1 Standard tolerances . 6
8.2 General values. 7
8.3 Sampling rate and value resolution . 7
8.4 Description of interfaces . 7
8.5 Restrictions on performing the tests . 7
8.6 Number of tested samples . 7
8.7 Test voltages . 7
8.8 Test procedure . 8
8.9 Parameter check . 8
8.10 Continuous parameter monitoring with drift analysis . 9
8.11 Physical analysis . 9
9 General requirements .10
9.1 General .10
9.2 Prerequisites regarding the system in which the component is applied .10
9.3 Component requirements .10
10 Tests and requirements .11
10.1 Test-01: nominal voltage range .11
10.1.1 Purpose .11
10.1.2 Test .11
10.1.3 Procedure .11
10.1.4 Requirement .12
10.2 Test-02: lower and upper transitory voltage ranges .12
10.2.1 Purpose .12
10.2.2 Test .12
10.2.3 Procedure .13
10.2.4 Requirement .14
10.3 Test-03: short term overvoltage.14
10.3.1 Purpose .14
10.3.2 Test .14
10.3.3 Procedure .15
10.3.4 Requirement .15
10.4 Test-04: supply component load dump control test .15
10.4.1 Purpose .15
10.4.2 Test .15
10.4.3 Procedure .16
10.4.4 Requirement .16
© ISO 2020 – All rights reserved iii

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ISO 21780:2020(E)

10.5 Test-05: starting profile .17
10.5.1 Purpose .17
10.5.2 Test .17
10.5.3 Procedure .18
10.5.4 Requirement .18
10.6 Test-06: long term overvoltage .18
10.6.1 Purpose .18
10.6.2 Test .18
10.6.3 Requirement .19
10.7 Test-07: overvoltage with consumer components which may supply electrical energy .19
10.7.1 Purpose .19
10.7.2 Test .19
10.7.3 Requirements for part 1 and part 2 .22
10.8 Test-08: decrease and increase of supply voltage .23
10.8.1 Purpose .23
10.8.2 Test .23
10.8.3 Requirement .23
10.9 Test-09: voltage ripples .23
10.9.1 Purpose .23
10.9.2 Test .24
10.9.3 Requirement .25
10.10 Test-10: reinitialisation .25
10.10.1 Purpose .25
10.10.2 Test .26
10.10.3 Requirement .26
10.11 Test-11: discontinuities in supply voltage .27
10.11.1 Purpose .27
10.11.2 Test .27
10.11.3 Requirements .28
10.12 Test-12: ground loss .28
10.12.1 Purpose .28
10.12.2 Requirements .32
10.13 Test-13: fault current .33
10.13.1 Purpose .33
10.13.2 Test .33
10.13.3 Requirement .34
10.14 Test-14: ground offset .35
10.14.1 Purpose .35
10.14.2 Test .35
10.14.3 Requirement .37
10.15 Test-15: short circuit in signal line and load circuit .37
10.15.1 Purpose .37
10.15.2 Test .37
10.15.3 Procedure .38
10.15.4 Requirements .38
10.16 Test-16: quiescent current .39
10.16.1 Purpose .39
10.16.2 Test .39
10.16.3 Requirements .40
Annex A (informative) Example of functional status and functional categories.41
Annex B (informative) Loss of GND using the example CAN communication .43
48
iv © ISO 2020 – All rights reserved

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ISO 21780:2020(E)

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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 32,
Electrical and electronic equipment and general system aspects.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2020 – All rights reserved v

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INTERNATIONAL STANDARD ISO 21780:2020(E)
Road vehicles — Supply voltage of 48 V — Electrical
requirements and tests
1 Scope
This document covers requirements and tests for the electric and electronic components in road
vehicles equipped with an electrical system operating at a nominal voltage of 48 V DC.
This includes the following:
— general requirements on 48 V DC electrical systems;
— voltage ranges;
— slow voltage transients and fluctuations (not including EMC).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 16750-1, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 1: General
ISO 16750-2, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 2: Electrical loads
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
EN 13018, Non-destructive testing — Visual testing — General principles
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
component
a part that is directly installed in a vehicle and is the Device Under Test (DUT)
3.2
fire
self-supporting combustion which spreads, uncontrolled, with time and in space and may result in
bright light, heat, smoke, burning or a combination of all the above
3.3
ground for 12 V/24 V electrical system
GND
12/24
ground pin on the 12 V/24 V electrical system
© ISO 2020 – All rights reserved 1

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ISO 21780:2020(E)

3.4
ground for 48 V electrical system
GND
48
ground pin on the 48 V electrical system
3.5
12 V/24 V positive voltage connection pin
U
12/24
positive voltage connection pin on the 12 V/24 V electrical system
3.6
48 V positive voltage connection pin
U
48
positive voltage connection pin on the 48 V electrical system
3.7
nominal 12 V/24 V supply voltage
U
N
voltage of the 12 V/24 V external supply distribution system
3.8
nominal 48 V supply voltage
U
48N
voltage of the 48 V external supply distribution system
3.9
maximum operating temperature
T
max
highest temperature of operation of the DUT
3.10
minimum operating temperature
T
min
lowest temperature of operation of the DUT
3.11
room temperature
T
RT
ambient temperature at which the test is performed
3.12
test temperature
T
test
temperature of the DUT at which the test is performed
4 Functional status
4.1 General
A component may include several functions which might have different functional statuses for the same
value of the influencing parameter. For the purpose of this document the influencing parameter is the
supply voltage.
The functional status is a minimum requirement.
The component functional behaviour, (including derating), relating to each chosen functional status
level and the customer perception (e.g. visual, acoustic, tactile and thermal), shall be defined and
agreed between the customer and supplier and described in the required component documentation.
See Annex A for application examples.
2 © ISO 2020 – All rights reserved

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ISO 21780:2020(E)

4.2 Functional status 1 (FS1)
The function shall meet a specified performance without deviation. Derating or switch-off is not
allowed.
4.3 Functional status 2 (FS2)
The function shall meet a specified performance with a specified variation below or above the specified
performance of FS1. Derating is allowed, switch-off is not allowed.
4.4 Functional status 3 (FS3)
The function may not provide the specified performance. Derating or switch-off is allowed. The function
shall automatically recover and return to the specified performance level if the necessary operating
conditions are met.
4.5 Functional status 4 (FS4)
The function may not provide the specified performance. Derating or switch-off is allowed. The function
shall recover and return to specified performance only after a change in vehicle operational status (e.g.
change of ignition status, vehicle restart) has occurred and if the necessary operating conditions are met.
4.6 Functional status 5 (FS5)
The DUT fails to perform one or more functions whilst the test parameters are applied, the DUT does
not set itself on fire as defined in 3.2. After application is terminated, the DUT can no longer be used
unless it is repaired or replaced
5 Supply voltage range
The supply voltage ranges are described in Figure 1.
© ISO 2020 – All rights reserved 3

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ISO 21780:2020(E)

Figure 1 — Supply voltage ranges
Upper overvoltage range (58 V – 60 V):
Reason for being in this voltage range could be a control error.
Overvoltage range (54 V – 58 V):
This voltage range may occur due to (short term) return of electrical energy or maybe a control error.
The system may operate only temporarily in this range.
Upper transitory voltage range (52 V – 54 V):
This range is intended for calibrating the storage media and for uptake of recovered energy.
The system may operate only temporarily in this range.
Nominal voltage range (36 V – 52 V):
The system is expected to operate in this range most of the time.
Lower transitory voltage range (31 V – 36 V):
The voltage may for example be in this range during boost or during cold crank.
The system may operate only temporarily in this range.
Undervoltage range (24 V – 31 V):
The voltage may for example be in this range during cold crank.
4 © ISO 2020 – All rights reserved

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ISO 21780:2020(E)

The system may operate only temporarily in this range.
Lower undervoltage range (0 V – 24 V):
Storage protection.
The voltage is not expected to be in this range except for short term discontinuities in the supply voltage
or due to long term parking.
6 Functional categories
The required performance, (e.g. torque of an electrical motor or flow rate of a water pump), shall be
specified for each relevant function of the DUT. The performance specified is then used as a reference
to enable the selection of a functional status level for each relevant function. The functional categories
which specify the changes in functional status of the DUT as a function of the 48 V supply voltage are
described in Table 2. Use Table 2 to select the required category
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 21780
ISO/TC 22/SC 32
Road vehicles — Supply voltage of 48
Secretariat: JISC
V — Electrical requirements and tests
Voting begins on:
2020­05­04
Véhicules routiers — Tension d'alimentation de 48 V — Exigences
électriques et essais
Voting terminates on:
2020­06­29
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 21780:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2020

---------------------- Page: 1 ----------------------
ISO/FDIS 21780:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH­1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/FDIS 21780:2020(E)

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Functional status . 2
4.1 General . 2
4.2 Functional status 1 (FS1) . 3
4.3 Functional status 2 (FS2) . 3
4.4 Functional status 3 (FS3) . 3
4.5 Functional status 4 (FS4) . 3
4.6 Functional status 5 (FS5) . 3
5 Supply voltage range . 3
6 Functional categories . 5
7 Operating modes . 6
8 General tests conditions . 6
8.1 Standard tolerances . 6
8.2 General values. 7
8.3 Sampling rate and value resolution . 7
8.4 Description of interfaces . 7
8.5 Restrictions on performing the tests . 7
8.6 Number of tested samples . 7
8.7 Test voltages . 7
8.8 Test procedure . 8
8.9 Parameter check . 8
8.10 Continuous parameter monitoring with drift analysis . 9
8.11 Physical analysis . 9
9 General requirements .10
9.1 General .10
9.2 Prerequisites regarding the system in which the component is applied .10
9.3 Component requirements .10
10 Tests and requirements .11
10.1 Test­01: nominal voltage range .11
10.1.1 Purpose .11
10.1.2 Test .11
10.1.3 Procedure .11
10.1.4 Requirement .12
10.2 Test-02: lower and upper transitory voltage ranges .12
10.2.1 Purpose .12
10.2.2 Test .12
10.2.3 Procedure .13
10.2.4 Requirement .14
10.3 Test­03: short term overvoltage.14
10.3.1 Purpose .14
10.3.2 Test .14
10.3.3 Procedure .15
10.3.4 Requirement .15
10.4 Test-04: supply component load dump control test .15
10.4.1 Purpose .15
10.4.2 Test .15
10.4.3 Procedure .16
10.4.4 Requirement .16
© ISO 2020 – All rights reserved iii

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ISO/FDIS 21780:2020(E)

10.5 Test-05: starting profile .17
10.5.1 Purpose .17
10.5.2 Test .17
10.5.3 Procedure .18
10.5.4 Requirement .18
10.6 Test­06: long term overvoltage .18
10.6.1 Purpose .18
10.6.2 Test .18
10.6.3 Requirement .19
10.7 Test-07: overvoltage with consumer components which may supply electrical energy .19
10.7.1 Purpose .19
10.7.2 Test .19
10.7.3 Requirements for part 1 and part 2 .22
10.8 Test-08: decrease and increase of supply voltage .23
10.8.1 Purpose .23
10.8.2 Test .23
10.8.3 Requirement .23
10.9 Test­09: voltage ripples .23
10.9.1 Purpose .23
10.9.2 Test .24
10.9.3 Requirement .25
10.10 Test­10: reinitialisation .25
10.10.1 Purpose .25
10.10.2 Test .26
10.10.3 Requirement .26
10.11 Test-11: discontinuities in supply voltage .27
10.11.1 Purpose .27
10.11.2 Test .27
10.11.3 Requirements .28
10.12 Test­12: ground loss .28
10.12.1 Purpose .28
10.12.2 Requirements .32
10.13 Test­13: fault current .33
10.13.1 Purpose .33
10.13.2 Test .33
10.13.3 Requirement .34
10.14 Test­14: ground offset .35
10.14.1 Purpose .35
10.14.2 Test .35
10.14.3 Requirement .37
10.15 Test­15: short circuit in signal line and load circuit .37
10.15.1 Purpose .37
10.15.2 Test .37
10.15.3 Procedure .38
10.15.4 Requirements .38
10.16 Test­16: Quiescent current .39
10.16.1 Purpose .39
10.16.2 Test .39
10.16.3 Requirements .40
Annex A (informative) Example of functional status and functional categories.41
Annex B (informative) Loss of GND using the example CAN communication .43
48
iv © ISO 2020 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/FDIS 21780:2020(E)

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 non­governmental, 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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 32,
Electrical and electronic equipment and general system aspects.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2020 – All rights reserved v

---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 21780:2020(E)
Road vehicles — Supply voltage of 48 V — Electrical
requirements and tests
1 Scope
This document covers requirements and tests for the electric and electronic components in road
vehicles equipped with an electrical system operating at a nominal voltage of 48 V DC.
This includes the following:
— general requirements on 48 V DC electrical systems;
— voltage ranges;
— slow voltage transients and fluctuations (not including EMC).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 16750­1, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 1: General
ISO 16750­2, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 2: Electrical loads
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
EN 13018, Non-destructive testing — Visual testing — General principles
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
component
a part that is directly installed in a vehicle and is the Device Under Test (DUT)
3.2
fire
self-supporting combustion which spreads, uncontrolled, with time and in space and may result in
bright light, heat, smoke, burning or a combination of all the above
3.3
ground for 12 V/24 V electrical system
GND
12/24
ground pin on the 12 V/24 V electrical system
© ISO 2020 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO/FDIS 21780:2020(E)

3.4
ground for 48 V electrical system
GND
48
ground pin on the 48 V electrical system
3.5
12 V/24 V positive voltage connection pin
U
12/24
positive voltage connection pin on the 12 V/24 V electrical system
3.6
48 V positive voltage connection pin
U
48
positive voltage connection pin on the 48 V electrical system
3.7
nominal 12 V/24 V supply voltage
U
N
voltage of the 12 V/24 V external supply distribution system
3.8
nominal 48 V supply voltage
U
48N
voltage of the 48 V external supply distribution system
3.9
maximum operating temperature
T
max
highest temperature of operation of the DUT
3.10
minimum operating temperature
T
min
lowest temperature of operation of the DUT
3.11
room temperature
T
RT
ambiemt temperature at which the test is performed
3.12
test temperature
T
test
temperature of the DUT at which the test is performed
4 Functional status
4.1 General
A component may include several functions which might have different functional statuses for the same
value of the influencing parameter. For the purpose of this document the influencing parameter is the
supply voltage.
The functional status is a minimum requirement.
The component functional behaviour, (including derating), relating to each chosen functional status
level and the customer perception (e.g. visual, acoustic, tactile and thermal), shall be defined and
agreed between the customer and supplier and described in the required component documentation.
See Annex A for application examples.
2 © ISO 2020 – All rights reserved

---------------------- Page: 7 ----------------------
ISO/FDIS 21780:2020(E)

4.2 Functional status 1 (FS1)
The function shall meet a specified performance without deviation. Derating or switch-off is not
allowed.
4.3 Functional status 2 (FS2)
The function shall meet a specified performance with a specified variation below or above the specified
performance of FS1. Derating is allowed, switch­off is not allowed.
4.4 Functional status 3 (FS3)
The function may not provide the specified performance. Derating or switch-off is allowed. The function
shall automatically recover and return to the specified performance level if the necessary operating
conditions are met.
4.5 Functional status 4 (FS4)
The function may not provide the specified performance. Derating or switch-off is allowed. The function
shall recover and return to specified performance only after a change in vehicle operational status (e.g.
change of ignition status, vehicle restart) has occurred and if the necessary operating conditions are met.
4.6 Functional status 5 (FS5)
The DUT fails to perform one or more functions whilst the test parameters are applied, the DUT does
not set itself on fire as defined in 3.2. After application is terminated, the DUT can no longer be used
unless it is repaired or replaced
5 Supply voltage range
The supply voltage ranges are described in Figure 1.
© ISO 2020 – All rights reserved 3

---------------------- Page: 8 ----------------------
ISO/FDIS 21780:2020(E)

Figure 1 — Supply voltage ranges
Upper overvoltage range (58 V – 60 V):
Reason for being in this voltage range could be a control error.
Overvoltage range (54 V – 58 V):
This voltage range may occur due to (short term) return of electrical energy or maybe a control error.
The system may operate only temporarily in this range.
Upper transitory voltage range (52 V – 54 V):
This range is intended for calibrating the storage media and for uptake of recovered energy.
The system may operate only temporarily in this range.
Nominal voltage range (36 V – 52 V):
The system is expected to operate in this range most of the time.
Lower transitory voltage range (31 V – 36 V):
The voltage may for example be in this range during boost or during cold crank.
The system may operate only temporarily in this range.
Undervoltage range (24 V – 31 V):
The voltage may for example be in this range during cold crank.
4 © ISO 2020 – All rights reserved

---------------------- Page: 9 ----------------------
ISO/FDIS 21780:2020(E)

The system may operate only temporarily in this range.
Lower undervoltage range (0 V – 24 V):
Storage protec
...