Bat & Alt Master Switches - Cirrus SR22 Pilot Operating Handbook

Section 7 Cirrus Design
Airplane Description SR22
BAT & ALT Master Switches
The rocker type electrical system MASTER switches are ON in the up
position and OFF in the down position. The switches, labeled BAT 2,
BAT 1, ALT 1, ALT 2 are located in the bolster switch panel
immediately below the instrument panel. These switches, along with
the AVIONICS power switch, control all electrical power to the
airplane.
Battery Switches
The BAT 1 and BAT 2 switches control the respective battery. Setting
the BAT 1 switch 'on' energizes a relay connecting BAT 1 to the MCU
Distribution Buses (also energizing the circuit breaker panel buses)
and the open contacts of the starter relay. Setting the BAT 2 switch 'on'
energizes a relay connecting BAT 2 to the circuit breaker panel
Essential Buses. Normally, for flight operations, all master switches will
be 'on.' However, the BAT 1 and BAT 2 switches can be turned 'on'
separately to check equipment while on the ground. Setting only the
BAT 2 switch 'on' will energize those systems connected to the circuit
breaker panel Essential Bus. If any system on the other buses is
energized, a failure of the Distribution Bus interconnect isolation diode
is indicated. When the BAT 1 switch is set to 'on,' the remaining
systems will be energized. To check or use avionics equipment or
radios while on the ground, the AVIONICS power switch must also be
turned on.
7-68 P/N 13772-001
Revision A7