I have a vehicle alternator with following parameters: 14V, 140A. In parallel to this alternator is connected 14.4V vehicle lead acid battery. The alternator is used as a power source for a load which consumes 115A. Please see the attached circuit diagram.
This circuit works in an operating point where the alternator delivers 105A and the rest 10A for the load are drawn from the vehicle battery. Due to this fact the vehicle battery is being discharged which is of course undesirable. I am not sure whether I understand why the vehicle battery is being discharged in a situation when the current drawn by the load is less than the alternator nominal current. Does anybody know the reason? Thanks in advance for any ideas.
The alternator is Bosch 0124 525 064. The combustion engine is simulated by a three phase induction motor supplied from the voltage source inverter. The induction motor has 1500 rpm synchronous speed and there is a belt transmission with ratio 2:1 so the alternator works at approximately 3000 rpm.