A battery can be modeled as an ideal source with an internal resistance - a constant voltage source with the resistor in series (the battery terminals correspond to the inlet to the voltage source and the point after the resistor) or a constant current source with a parallel resistor (battery terminals are across the resistor). These models exhibit a drop in terminal voltage as the current provided by the battery increases. Apply this model for the situations described below (start with a diagram):
a) When measured with open circuit (no load - zero current draw) the terminals of a battery show a voltage of 13.6 volts. When delivering 10. amps to an external load, the voltage drops to 11.2 volts. What is the value of the constant voltage source (Vs) and the internal resistance (Rs)? (hint: draw circuit, use KVL & Ohm's law)
b) A car battery has an open circuit voltage of 12.6 Volts. The terminal voltage drops to 9.6 Volts when the battery supplies 60. Amps to a starter motor. Develop a model for the battery which matches these characteristics:
i. using a constant voltage source as part of the model.
ii. using a constant current source as part of the model.