Electrical System; Power Generation - Cirrus SR22 Pilot Operating Handbook

Cirrus Design
SR22

Electrical System

The airplane is equipped with a two-alternator, two-battery, 28-volt
direct current (VDC) electrical system designed to reduce the risk of
electrical system faults. The system provides uninterrupted power for
avionics, flight instrumentation, lighting, and other electrically operated
and controlled systems during normal operation.

Power Generation

Primary power for the airplane is supplied by a 28-VDC, negative-
ground electrical system. The electrical power generation system
consists of two alternators controlled by a Master Control Unit (MCU)
mounted on the left side of the firewall and two batteries for starting
and electrical power storage.
Alternator 1 (ALT 1) is a gear-driven, internally rectified, 100-amp
alternator mounted on the right front of the engine. Alternator 2 (ALT 2)
is a belt-driven, internally rectified, 70-amp alternator mounted on the
front left of the engine. ALT 1 is regulated to 28 volts and ALT 2 is
regulated to 28.75 volts. Both alternators are self-exciting and require
battery voltage for field excitation in order to start up - for this reason,
the batteries should not be turned off in flight.
Storage
Battery 1 (BAT 1) is an aviation grade 12-cell, lead-acid, 24-volt, 10-
amp-hour battery mounted on the right firewall. BAT 1 is charged from
the Main Distribution Bus 1 in the MCU.
Battery 2 (BAT 2) is composed of two 12-volt, 7-amp-hour, sealed,
lead-acid batteries connected in series to provide 24 volts. Both BAT 2
units are located in a vented, acid-resistant container mounted behind
the aft cabin bulkhead (FS 222) below the parachute canister. BAT 2 is
charged from the circuit breaker panel ESS BUS 1.
P/N 13772-004 P/N 13772-004
Revision 1
Section 7
Systems Description
7-51 7-51