Mechanism explanations:
Arbin’s MITS software uses pulse method to calculate IR. In order to achieve better accuracy, the software measure the IR 10 times and take the average.
The pulse looks like the graph bellows:
IIR is the amplitude value
T2 is the Extra Control value1
I0 is the offset value
IR Calculation Formula:
IR = Average {(Voltage at P2 – Voltage at P3)/ (2IIR)}
The schedule writing for IR calculation is quite simple.
You will only need 2 steps:
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Rest step: mainly play the role of initial safety check
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Internal Resistance steps
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Amplitude: Amplitude determines the applied current value. For optimized accuracy, the applied current value should generate at least 10mV voltage change during the IR measurement. In general, the current should be at least 0.1C of your battery.
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You can also set the current range by filling up suitable number in the filed of Max Current (A)
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Current range are written on the label sticked on Arbin chassis. For example, you can see all the range from I1 to I6 as in the picture bellows.
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You should only put the value that are written on the label, in this case 5A, 1A, 0.1A, 0.01A, 0.001A, 0.0001A. If you put 0 (default), the range will be choose automatically by the machine
Extra Control Value1:
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This value determines the current pulse length before voltage change is measured. It is determined by your IR test needs(Ohmic resistance or polarization resistance), this value should be at least 100ms.
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Offset: This is the offset current value(A), at default value 0, the output current pulse will be symmetric.
Above is IR measuring with Arbin’s method. If you want to follow an international standard, you can refer to this article: How to perform Internal Resistance measurement accroding to IEC 61960 with Arbin?
