When the battery charger operates and charges the battery, does it also continue to feed the hot batt and switched hot batt busses? Or does it just charge the battery and the battery powers those busses?
Each battery charger also operates as a TRU when not in the charge mode.
[737-600/700/800/900 MAINTENANCE MANUAL - ELECTRICAL POWER - DISTRIBUTION - GENERAL DESCRIPTION]
The main battery charger is the primary power supply for the hot and switched hot battery bus. The auxiliary battery and its charger connect in parallel when the dual battery remote control circuit breaker (RCCB) is closed. This happens only during conditions when the main battery must supply standby AC and DC power.
[737-600/700/800/900 MAINTENANCE MANUAL - DC GENERATION - DISTRIBUTION AND CONTROL - GENERAL DESCRIPTION]
The main battery charger and auxiliary battery charger give a DC voltage output to charge their respective battery. Each charger operates like a TRU after the battery gets to full charge. The main battery charger sends a constant DC voltage to the battery and the hot and switched hot battery buses. The auxiliary battery and auxiliary battery charger power DC buses only during non-normal conditions.
[737-600/700/800/900 MAINTENANCE MANUAL - DC GENERATION SYSTEM - GENERAL DESCRIPTION]
Now, you decide to use the BATT position , what happens?
Which switch are you referring to? Do you mean:
- STANDBY POWER to BAT posiiton;
- BAT to OFF position;