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I would think you just hook up different resistors as a load, and watch the supplied voltage. Since voltage drop with increasing current (within the capacity of the battery used) is caused by internal resistance, you could calculate that resistance.
1. Monitor the voltage with no load.
2. Add a load of a known current (for example 1 Amp or 10 Amps)
3. Monitor the voltage again with the load connected.
Now use Ohms law, R = V / I. R will be the internal resitance, V the amount the voltage dropped and I is the load current you applied.
1. Monitor the voltage with no load.
2. Add a load of a known current (for example 1 Amp or 10 Amps)
3. Monitor the voltage again with the load connected.
Now use Ohms law, R = V / I. R will be the internal resitance, V the amount the voltage dropped and I is the load current you applied.
i think that is dc Method .anyway i have problem with Choice load in this method .i want measure IR for battery that type is 100 A.h To 4000 A.h
Do You have an idea how to choose load for Measure IR for 100 A.h To 4000 A.h Battery
Generally, the bigger the battery the lower the internal resistance will be so to get meaningful results you would have to use a load of say 10% of maximum current. The internal resistance is dependant on several factors, some electrical and some chemical so you might get a slightly different reading if you measured at zero load to 10% than at say 20% to 30% but they will be similar.
For heavy load, consider heating elements from domestic room heaters, they are usually rated in hundreds or thousands of Watts so they make a safe low-resitance load. You may have to modify them if you want a particular resitance but the calculation will remain the same as long as you know what thir native resistance is.
thanks brian
I've read many articles about the internal resistance.
There are different terms.
The Ac method is on of them .
in this method induction a sine wave to the battery and measure phase shift between Voltage & Current that named Impedance ?
and Ferqunce range betwen 80 hertz to 100 hertz .
And in this method we didn't need to heavy load .
Are Suggest this method to me ?
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