- #1
needingtoknow
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Homework Statement
Why is the formula for internal resistance for a charging battery v = e + Ir?
When the battery is supplying I to the circuit I understand why the terminal voltage, V, equals emf - IR (voltage lost by internal resistance), but if a battery is charging, why is the voltage lost by internal resistance being added to the ideal voltage, e? The resistance is still there right, even if it is charging, so shouldn't the sign in front of Ir still be negative?