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Old 08-31-2010, 03:13 PM   #16 (permalink)
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Originally Posted by redbird300 View Post
"To determine the internal resistance, first it is necessary to measure the open circuit voltage of the cell. Then a load should be connected across the cell causing a current to flow. This will reduce the cell voltage due to the IR voltage drop across the cell which corresponds to the cell's internal resistance. The cell voltage should then be measured again when the current is flowing. The resistance is calculated by ohms law from the voltage difference between the two measurements and the current which is flowing through the cell."
How does this relate to the discharge rating in "C" of a battery? I like the explanation of why the voltage drops across the battery when connected to a load, but I wonder what happens when large amp draws are used. I suppose the internal resistance R = Vdrop / I should stay the same up to the max discharge rate? And then what?
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