IEC 62282-4-202:2023

IEC 62282-4-202 ®
Edition 1.0 2023-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fuel cell technologies –
Part 4-202: Fuel cell power systems for propulsion and auxiliary power units –
Unmanned aircrafts – Performance test methods

Technologies des piles à combustibles –
Partie 4-202: Systèmes à piles à combustible pour les groupes auxiliaires de
puissance et de propulsion – Aéronefs sans pilote – Méthodes d'essai des
performances
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IEC 62282-4-202 ®
Edition 1.0 2023-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fuel cell technologies –
Part 4-202: Fuel cell power systems for propulsion and auxiliary power units –

Unmanned aircrafts – Performance test methods

Technologies des piles à combustibles –

Partie 4-202: Systèmes à piles à combustible pour les groupes auxiliaires de

puissance et de propulsion – Aéronefs sans pilote – Méthodes d'essai des

performances
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.070, 49.020 ISBN 978-2-8322-7587-0

– 2 – IEC 62282-4-202:2023 © IEC 2023
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Fuel cell power system requirements for UAs . 9
4.1 System configuration . 9
4.2 Appearance and structure . 10
4.3 General technical requirements. 10
5 Test preparation . 11
5.1 General . 11
5.2 Test environment . 11
5.3 Test equipment and accuracy . 11
6 Test methods . 12
6.1 Start-up time . 12
6.2 Time to achieve rated power output . 12
6.3 Rated power output . 12
6.4 Continuous running duration . 12
6.5 Peak power output . 12
6.6 Output voltage range . 13
6.7 Electric efficiency . 13
6.8 Start-up and shutdown methods . 13
6.9 Shutdown time . 13
6.10 Acoustic noise level . 14
6.11 Data transmission . 14
6.12 Enclosure H concentration . 15
6.13 H concentration in fuel exhaust . 15
6.14 Enclosure IP code . 15
6.15 H leakage rate . 15
6.16 Warning and monitoring . 16
Annex A (informative) Suggested aging test procedure for a fuel cell power system
for a UA . 17
Annex B (informative) Guidelines for test reports . 18
B.1 General . 18
B.2 Title page . 18
B.3 Table of contents . 18
B.4 Summary report . 18
B.5 Detailed report . 19
B.6 Full report . 19
Bibliography . 20

Figure 1 – General configuration of a fuel cell power system for UAs . 10
Figure 2 – Acoustic noise measurement points for fuel cell power system . 14

Table 1 – Test equipment and accuracy . 11
Table 2 – Acoustic noise level correction . 14
Table A.1 – Suggested aging test procedure for a fuel cell power system for a UA . 17

– 4 – IEC 62282-4-202:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FUEL CELL TECHNOLOGIES –
Part 4-202: Fuel cell power systems for propulsion and auxiliary
power units – Unmanned aircrafts – Performance test methods

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,
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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
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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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
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the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 62282-4-202 has been prepared by IEC technical committee 105: Fuel cell technologies. It
is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
105/998/FDIS 105/1009/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 62282 series, published under the general title Fuel cell technologies,
can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
– 6 – IEC 62282-4-202:2023 © IEC 2023
INTRODUCTION
This part of IEC 62282-4 provides consistent and repeatable test methods for the electrical,
thermal and environmental performance of fuel cell power systems for unmanned aircrafts.
The IEC 62282-4 series deals with the safety, performance, and interchangeability of fuel cell
power systems for propulsion for categories of vehicles other than road vehicles and for
auxiliary power units (APUs). Among the categories covered by the IEC 62282-4 series, this
document focuses on fuel cell power systems for unmanned aircrafts because there is an urgent
demand for such an application in the world.
This part of IEC 62282-4 describes type tests and their test methods only. No routine tests are
required or identified, and no performance targets are set in this document.
The purpose of this document is to evaluate the fuel cell system in the various combinations of
fuel cell and unmanned aircrafts. This document provides a framework for designing and
evaluating a fuel cell system for use specifically in an unmanned aircraft.
This part of IEC 62282-4 can be used by manufacturers of fuel cell power systems used for
unmanned aircrafts or those who evaluate the performance of their systems for certification
purposes.
Users of this document selectively execute test items that are suitable for their purposes from
those described in this document. This document is not intended to exclude any other methods.

FUEL CELL TECHNOLOGIES –
Part 4-202: Fuel cell power systems for propulsion and auxiliary
power units – Unmanned aircrafts – Performance test methods

1 Scope
This part of IEC 62282 covers performance test methods of fuel cell power systems intended
to be used to power unmanned aircrafts, including general requirements, start-up, shutdown,
power output, continuous running time, electric efficiency, data transmission, warning and
monitoring, environmental compatibility, etc.
The scope of this document is limited to electrically powered unmanned aircrafts with a
maximum take-off mass not exceeding 150 kg (i.e. level 5 or lower unmanned aircrafts (UAs)).
This document applies to fuel cell power systems with a rated output voltage not exceeding
220 V DC for outdoor use.
This document applies only to compressed gaseous hydrogen-fuelled fuel cell power systems.
This document does not apply to reformer-equipped fuel cell power systems.
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.
IEC 60050-485, International Electrotechnical Vocabulary (IEV) – Part 485: Fuel cell
technologies, available at http://www.electropedia.org
IEC 60529, Degrees of protection provided by enclosures (IP Code)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-485 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp

– 8 – IEC 62282-4-202:2023 © IEC 2023
3.1
unmanned aircraft
unmanned aerial vehicle
remotely-piloted aircraft
UA
UAV
RPA
aircraft without a human pilot aboard with its flight being controlled either autonomously by
onboard control systems or by the remote control of a pilot on the ground
[SOURCE: ISO 21384-4:2020, 3.67 and 3.79, modified – The terms are listed under a single
entry as equivalent terms and the definition has been adapted for the purposes of this document
and to add clarity.]
3.2
fuel cell power system for UA
fuel cell power system onboard a UA that provides electric power for propulsion and non-
propulsion needs of the UA during its flight
3.3
start-up time
time duration from the moment a signal is sent out or an action is taken to start up the fuel cell
power system to the moment the fuel cell power system is able to provide net electric power
output
[SOURCE: IEC 60050-485:2020, 485-20-05, modified – The definition has been adapted for the
purposes of this document and to add clarity.]
3.4
shutdown time
time duration from the moment a signal is sent out or an action is taken to shut down the fuel
cell power system to the moment the fuel cell power system shuts down completely
[SOURCE: IEC 60050-485:2020, 485-20-04, modified – The definition has been adapted for the
purposes of this document and to add clarity.]
3.5
rated power output
maximum continuous DC power output of the fuel cell power system when operated under
normal conditions specified by the fuel cell power system manufacturer
Note 1 to entry: A continuous running duration of the fuel cell power system at rated power output can be agreed
upon by the related parties.
3.6
peak power output
maximum DC power output of the fuel cell power system that can last for a short time
Note 1 to entry: It is recommended that the time duration be more than 2 min.
Note 2 to entry: The time duration can also be agreed upon by the related parties based on actual situations.

3.7
output voltage range
under the normal operational conditions specified by the fuel cell power system manufacturer,
range from the lowest output voltage to the highest output voltage of the fuel cell power system
in the entire process from start-up, to operation, to shutdown
Note 1 to entry: It is important that the DC output voltage of the fuel cell power system is always within the input
voltage range of the DC/DC or DC/AC converter or the electronic speed controller (ESC) used on the UA by the UA
manufacturer.
3.8
continuous running duration
under the normal operational conditions specified by the fuel cell power system manufacturer,
time duration the fuel cell power system can last at the rated power output with its output voltage
within the output voltage range described in 3.7
Note 1 to entry: The DC/DC or DC/AC converter or the electronic speed controller used on the UA can either be
damaged or not function effectively when the output DC voltage from the fuel cell power system is out of the input
voltage range of the DC/DC or DC/AC converter or the electronic speed controller.
3.9
H management subsystem
combination of all the parts, apparatus, devices, pipes, connectors and controls that is
responsible for sending hydrogen from the H storage vessel to the fuel cell module
Note 1 to entry: The fuel management subsystem can include all or part of the following: stop valve, filter,
electromagnetic valve, pressure regulator, fusible valve, excess flow valve, pressure release valve, unidirectional
valve, ejector, recirculation pump, pressure sensor, temperature sensor, pressure gauge, flowmeter, controls.
Note 2 to entry: The hydrogen storage vessel is not included in the H management subsystem. Parts that
accompany the hydrogen storage vessel to be supplied to the fuel cell power system manufacturer can be considered
not the responsibility of the fuel cell power system manufacturer.
3.10
H leakage rate
ratio of the amount of hydrogen leaking out of the fuel cell power system to the amount of
hydrogen theoretically required by the fuel cell power system at the rated power output
3.11
power management subsystem
device or system that manages the DC power from both the fuel cell module and the energy
storage subsystem, sends unregulated main DC power to the UA’s propulsion system, and
sends either regulated or unregulated minor DC or AC power to the power consuming devices
within the fuel cell power system for the internal power needs
4 Fuel cell power system requirements for UAs
4.1 System configuration
Figure 1 illustrates the general fuel cell power system configuration pertaining to this document,
and shows the system boundary and physical items entering and leaving the system.
The fuel cell power system can contain part or all of the subsystems.

– 10 – IEC 62282-4-202:2023 © IEC 2023

Figure 1 – General configuration of a fuel cell power system for UAs
The power management subsystem provides unregulated DC power to the DC/DC or DC/AC
converter or the electronic speed controller provided by the UA manufacturer. In other words,
any device that is required to regulate the main DC power from the fuel cell power system to
propel the UA is not part of the fuel cell power system in this document. However, the power
management subsystem provides unregulated or regulated DC or AC power for the internal
power need of the fuel cell power system.
4.2 Appearance and structure
1) The appearance of the fuel cell power system shall show no signs of mechanical damage,
cracks, dents, rust, and obvious deformation.
2) There shall be no sharp edges and corners that can cause injury to human beings.
3) During the normal operation of the fuel cell power system, parts, modules, subsystems, and
connections within the system shall be sturdy and reliable, without loss of stability,
deformation, breaking and abrasion.
4) The communications connection ports, the power connection ports, the user interfaces, and
the hydrogen inlet and outlet ports of the fuel cell power system shall be labelled clearly.
5) The positive voltage terminal and the negative voltage terminal of the fuel cell power system
shall be labelled clearly.
4.3 General technical requirements
1) The fuel cell power system shall be operational under the following environment conditions:
temperature: −5 °C to 40 °C; pressure: 86 kPa to 106 kPa, relative humidity: ≥ 60 %.
2) The fuel cell power system shall be able to provide enough electric power to the propulsion
system, ancillaries, payload, etc. of the UA from take-off to landing during normal flights.
3) The fuel cell power system itself or the communications system of the UA shall be able to
communicate with the ground control system, and provide information on the fuel cell
system’s state-of-health, remaining fuel, battery’s voltage, alarm conditions, etc., provided
the tele-message transmission is under normal conditions.

4) In situations where the UA loses communication with the ground control system, the fuel
cell power system shall be able to continue providing electric power to the propulsion
system, ancillaries, payload, etc. of the UA, and carry out pre-designated plans under such
circumstances.
5) The key operational parameters of the fuel cell power system shall be able to be monitored
and controlled in-situ.
5 Test preparation
5.1 General
According to the guidelines or instructions from the fuel cell power system manufacturer, put
the fuel cell power system in the testing environment, make all the connections both mechanical
and electrical, and connect the fuel cell power system to an electric load bank and other
measuring and monitoring devices.
If the environment temperature is out of the 15 °C to 25 °C range, leave the fuel cell power
system in the environment for at least 2 h before the test is started.
During the tests, the results are read and recorded every second.
5.2 Test environment
The normal test environment conditions are as follows:
– temperature: 20 °C ± 5 °C;
– pressure: 86 kPa to 106 kPa;
– relative humidity: ≥ 60 %.
If the fuel cell powered UA is going to be used out of the above environmental conditions, the
parties involved should take those factors into consideration, and if necessary and agreed, the
fuel cell power system should be tested under the intended conditions.
Detailed testing conditions should be given in the test reports.
NOTE Both the power output of the fuel cell power system and the lifting force of the UA decline with the increase
in altitude.
5.3 Test equipment and accuracy
The major equipment and the accuracy used for the performance test are given in Table 1.
Table 1 – Test equipment and accuracy
Equipment Unit Accuracy
Barometer kPa ±1 % (full scale)
Humidity meter % ±3 % (RH)
Temperature sensor °C ±1,0
Pressure sensor kPa ±1 % (full scale)
Flowmeter l/min, g/min ±1 % (full scale)
Flow rate controller l/min, g/min ±1 % (full scale)
Voltmeter V ±1 % (full scale)
Current meter A ±1 % (full scale)
H concentration sensor % vol ±1 % (full scale)
Noise meter dB ±1
– 12 – IEC 62282-4-202:2023 © IEC 2023
6 Test methods
6.1 Start-up time
After the fuel cell power system is set up and all the test equipment is in place, start the fuel
cell power system by sending a start-up signal to the fuel cell power system, and measure the
time duration from the moment the start-up signal is sent out to the moment the fuel cell power
system has net electric power output.
6.2 Time to achieve rated power output
After the start-up is completed as described in 6.1, set the load of the load bank to the rated
power of the fuel cell power system, apply the load, and measure the time duration from the
moment the rated power load is applied to the moment the fuel cell power system reaches the
rated power output.
6.3 Rated power output
Operate the fuel cell power system continuously with a fixed load equivalent to the rated power
output given by the fuel cell power system manufacturer for a time duration as long as the
continuous running duration given by the fuel cell power system manufacturer, read and record
the output voltage of the fuel cell power system. If the output voltage is within the output voltage
range given by the fuel cell power system manufacturer, then the rated power output and the
continuous running duration given by the fuel cell power system manufacturer are confirmed.
The allowable variation of rated power output during the test is ±3 %.
NOTE 1 If the fuel cell power system cannot operate at the rated power output for the continuous running duration
given by the fuel cell power system manufacturer, then either the rated power output or the continuous running
duration given by the fuel cell power system manufacturer is incorrect.
NOTE 2 If the fuel cell power system can operate at the rated power output for the continuous running duration
given by the fuel cell power system manufacturer, but the voltage output drifts out of the output voltage range given
by the fuel cell system manufacturer, then either the rated power output or the continuous running duration or the
output voltage range given by the fuel cell power system manufacturer is incorrect.
NOTE 3 As the fuel cell power system ages with time, the rated power output or the continuous running duration is
likely to decline, a suggested aging test procedure is given in Annex A for reference.
6.4 Continuous running duration
After the fuel cell power system is started, increase its power output to the rated power output,
set up the load to the fixed power output mode, measure the time duration from the moment the
fuel cell power system is able to provide the rated power output to the moment the output
voltage of the fuel cell power system drifts out of the output voltage range.
NOTE If the test of 6.3 confirms the continuous running duration given by the fuel cell system manufacturer, it will
possibly not be necessary to carry out the test of 6.4.
6.5 Peak power output
Operate the fuel cell power system at the peak power output given by the fuel cell power system
manufacturer for the time duration provided by the fuel cell power system manufacturer. If the
output voltage of the fuel cell power system is within the output voltage range, then this power
output is the peak power output of the fuel cell power system.
The allowable variation of peak power output during the test is ±3 %.
NOTE If the output voltage of the fuel cell power system drifts out of the output voltage range given by the fuel cell
power system manufacturer during the test, either the peak power, or the duration that fuel cell power system can
operate at the peak power, or the output voltage range given by the fuel cell power system manufacturer is incorrect.

For a fixed wing UA or a rotary wing UA, the peak power output of the fuel cell power system
should be at least 1,5 times its rated power output.
For a fixed wing UA that takes off and lands vertically, the peak power output of the fuel cell
power system should be at least 3,0 times its rated power output.
6.6 Output voltage range
Record the voltage from start-up, to rated power operation for the continuous running duration
given by the fuel cell system manufacturer, to peak power operation for the duration given by
the fuel cell system manufacturer, and to shutdown of the entire operation process. The lowest
to the highest output DC voltage of the fuel cell power system is the output voltage range.
NOTE The rated power output, continuous running duration, peak power output, peak power output duration, and
output voltage range are all related, particularly for using open-cathode air-cooled stacks.
6.7 Electric efficiency
After the fuel cell power system is started, disconnect the internal power supply subsystem, and
operate the fuel cell power system at the rated power output P for 0,5 h; divide the net
rated
energy output from the fuel cell power system by the hydrogen energy input to the fuel cell
power system (using the lower heating value, 242 kJ/mol) within this 0,5 h to calculate the
electric efficiency of the fuel cell power system as shown by Equation (1):
= [0,5 × P /(242 × Q /3 600)] × 100 %
η
(1)
ne rated cons
where
η is the electric efficiency (%);
ne
P is the rated power output (kW);
rated
Q is the cumulated hydrogen consumption (mol).
cons
6.8 Start-up and shutdown methods
For the manual start-up and shutdown methods, start up or shut down the fuel cell power system
manually, check whether the fuel cell power system can be started or shut down normally.
For the remote control start-up and shutdown methods, start up or shut down the fuel cell power
system remotely by electronic signals from an electronic device such as a remote controller or
a computer, check whether the fuel cell power system can be started or shut down normally.
For the autonomous start-up and shutdown methods, set up a time to start up or shut down the
fuel cell power system autonomously, check whether the fuel cell power system starts or shuts
down normally.
NOTE A fuel cell power system has at least one of the following three start-up and shutdown methods: manual,
remote control, and autonomous.
6.9 Shutdown time
Send a shutdown signal manually, remotely, or autonomously to the fuel cell power system that
is running at the rated power output, measure the time duration from the moment the signal is
sent out to the moment the fuel cell power system shuts down completely.
NOTE IEV 485-19-01 defines shutdown as the "sequence of operations that occurs to transition a fuel cell power
system from the operational state to the passive state, the pre-generation state, or the cold state."

– 14 – IEC 62282-4-202:2023 © IEC 2023
6.10 Acoustic noise level
Operate the fuel cell power system at the rated power output. Envision the fuel cell power
system being a box having six sides as shown in Figure 2, measure the noise levels in the front,
back, left, and right four directions at points A, B, C, and D. The noise measurement equipment
is kept at a 1 m distance from each side of the fuel cell power system in all the four measurement
directions, and is 1,2 m above the bottom surface.

Figure 2 – Acoustic noise measurement points for fuel cell power system
Turn off the fuel cell power system, and measure the background noise levels the same way.
If the measured noise levels are no more than 10 dB over the background noise level, correct
the noise levels according to Table 2.
Table 2 – Acoustic noise level correction
Difference between the measured noise levels and the
3 4 5 6 7 8 9
background noise level (dB)
Correction (dB) −3 −2 −1
6.11 Data transmission
Connect a communication device or a data transmission device to the communications port or
data transmission port of the fuel cell power system, start up the fuel cell power system,
increase the power output to the rated power output, operate at the rated power output for a
few minutes, increase the power output to the peak power output, operate at the peak power
output for at least 1 min, decrease the power output to the rated power output, disconnect the
external power load and wait for 1 min, then shut down the fuel cell power system. Report the
transmitted data received by the communication device at each of the above stages.

6.12 Enclosure H concentration
Place the fuel cell power system into the enclosure of its own, or the enclosure of the UA at the
designated location for the fuel cell power system, or into an enclosure that has a similar space
as that of the enclosure of the UA for hosting the fuel cell power system, operate the fuel cell
power system at the rated power output, and measure the hydrogen concentration using a
hydrogen concentration sensor that is placed at the highest point of the interior of the enclosure
for a time period until the hydrogen concentration does not show apparent changes.
The maximum concentration allowable should be less than 25 % of the lower flammability limit
(LFL) of hydrogen.
NOTE Any H purged out of the fuel cell power system is conducted out of the enclosure.
6.13 H concentration in fuel exhaust
Operate the fuel cell power system at the rated power output, place a hydrogen concentration
sensor 10 cm from the centre of the exhaust port and on an imaginary line that is perpendicular
to the cross-section of the exhaust port, measure the hydrogen concentration for no less than
10 min.
NOTE The H concentration in the fuel exhaust can be higher than 50 % LFL during the short purging time, but if
the H concentration is higher than 50 % LFL continuously, there is something wrong with the fuel cell power system.
6.14 Enclosure IP code
Based on the IP code given by the fuel cell power system manufacturer, perform the IP code
test according to IEC 60529 at the rated power output.
For the fuel cell power system that is installed within an enclosure or within the shell of the UA,
the test should be carried out within the enclosure or the shell of the UA.
6.15 H leakage rate
Install a flowmeter before the hydrogen inlet to the fuel cell module, set the hydrogen inlet
pressure to the working pressure provided by the fuel cell power system manufacturer, open
the hydrogen exhaust port of the fuel cell power system, supply hydrogen to the fuel cell power
system for 1 min, then close the hydrogen exhaust port. Wait for 10 min, then record the
hydrogen flow rate shown by the hydrogen flowmeter. Convert the hydrogen flow rate to mol/s,
and this is q .
leak
The theoretical hydrogen consumption rate at the rated power output is given by Equation (2):
q = NI/(2F)
(2)
t
where
q is the theoretical hydrogen consumption rate at the rated power output (mol/s);
t
N is the number of cells in the fuel cell module;
I is the current of the fuel cell module (A);
F is the Faraday constant (96485 C/mol).

– 16 – IEC 62282-4-202:2023 © IEC 2023
Then, the hydrogen leakage rate is calculated by Equation (3):
η = (q /q ) × 100 %
(3)
leak leak t
The H leakage rate should be smaller than 0,5 %.
NOTE The full scale of the flowmeter can be chosen at 1 % to 5 % q .
t
6.16 Warning and monitoring
Set up the parameters described below out of the normal ranges, and observe if the fuel cell
power system sends out warning signals:
1) the hydrogen outlet pressure of the hydrogen cylinder is lower than the lowest allowable
pressure (the fuel cell power system is not required to provide net power output);
2) the hydrogen pressure at the hydrogen inlet to the fuel cell module is lower than the
designated lowest value (the fuel cell power system is not required to provide net power
output);
3) the hydrogen pressure at the hydrogen inlet to the fuel cell module is higher than the
designated highest value (the fuel cell power system is not required to provide net power
output);
4) the output DC voltage of the fuel cell power system is lower than the designated lowest
value (the fuel cell power system shall be in the operational state and offer net power
output);
5) the output DC voltage of the fuel cell power system is higher than the designated highest
value (the fuel cell power system is not required to provide net power output);
6) the current output of the fuel cell power system is higher than the designated over-current
limiting value (the fuel cell power system shall be in the operational state and offer net power
output);
7) the ambient temperature is lower than the designated lowest temperature limit (the fuel cell
power system is not required to provide net power output);
8) the ambient temperature is higher than the designated highest temperature limit (the fuel
cell power system is not required to provide net power output);
9) the voltage output of the energy storage module is lower than the designated lowest limit
(the fuel cell power system is not required to provide net power output);
10) the enclosure hydrogen concentration is higher than 50 % of the LFL of hydrogen (the fuel
cell power system is not required to provide net power output).
NOTE Guidelines for test reports are given in Annex B for reference.

Annex A
(informative)
Suggested aging test procedure for a fuel cell power system for a UA
The procedure for the lifetime test of the fuel cell power system for a UA can be agreed upon
by related parties. The basic principle to follow is that the power output and the power transients
of the fuel cell power system should be as close as possible to the actual situation when the
UA is used. Table A.1 gives a suggested procedure that can be referenced.
The 2-min durations at the peak power output are based on the consideration that the UA will
possibly require the peak power output for a maximum of 2 min during take-off, acceleration,
changing directions, or encountering air turbulence.
The 45-min shutdown duration is based on the consideration that the formation of the
hydrogen/air boundary at the anodes of the fuel cell module during start-up and shutdown will
impact the lifetime of the fuel cell power system, and a tim
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