Battery capacity testing according to IEC 61951-2 Edition 4.1 10-2022

[Kiriakos GR]

At our times, IEC 61951-2 Edition 4.1 10-2022, this is latest known standard, for battery capacity evaluation.
An Accredited Testing Laboratory, this it should buy this IEC document, and to perform the testing according to specific steps.

All IEC documentation this is copyright protected, and I am also bonded with the obligation of protecting copyright's.

But, IEC this also mention electrical specifications, measurement tolerances per parameter, that the testing equipment, this should comply too, so the testing report this to be valid.

4  Parameter measurement tolerances
The overall accuracy of controlled or measured values, relative to the specified or actual values, shall be within the following tolerances:
a) ±1 % for voltage
b) ±1 % for current
c) ±1  % for capacity

d) ±2 °C  for temperature
e) ±0,1 %  for time (sync clock)

f) ±0,1 mm for dimensions
g) ±5 %  for humidity.

These tolerances comprise the combined accuracy of the measuring instruments, the
measurement techniques used and all other sources of error in the test procedure.
The details of the instrumentation used shall be provided in each report of results.
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At Computerized Battery Analyzer systems, and even down to hobbyist level battery discharge gadgets, the most important and overlooked specification this is time accuracy.   
How accurate is the time clock ?  At battery discharge we expecting accurate mAH measurement.
Every serious lab technician, he can use quality measurement equipment so to inspect, testing system voltage and current calibration, and temperature.
But time accuracy this is difficult to be verified.

From the side of testing system micro-controller, us experts know, an low cost micro-controller this can not obtain accurate clock without the addition of external crystal  (frequency lock against drift).
Frequency crystal, this is another component with accuracy tolerances of it own.

As far I am aware of, when timing synchronization of several test equipment, this is of high importance, an external high precision frequency generator, this delivers an master clock pulse.
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Currently all consumer level charge/discharge testers, they might operate by the use of HOLTEK micro-controller.
The most accurate design at that class will include HOLTEK micro-controller, plus a frequency crystal.   
Ansmann PowerLine 4 PRO, this is such an example.

At medium class discharge testers with single channel or bay, my TEC-06 Battery Capacity Tester, this using STCmicro a new generation of enhanced 8051 Micro controller plus a frequency crystal.

At Computerized Battery Analyzer systems, everything gets more complicated, they start from controlling eight channels, and they can further expand.
Timing accuracy this becomes an significant challenge.
Such systems belong to high dollar solutions, because they are custom work, and the count of electronic components this is greater.


I will stop here the technical descriptions, and I will simply mention our fresh problem as parts of the greater technical society.
In European union we do not have form yet a body, this to offer certification at Computerized Battery Analyzer systems.

Currently, such system development this is custom work, an Australian brand this has their own offering, an Canadian brand this has their own offering, and China develops also solutions for small and big industrial customers.