Electrical System; Power Generation - Cirrus SR22 Pilot Operating Handbook

S 7: A
ECTION IRPLANE AND
E S
LECTRICAL YSTEM

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 alter-
nator 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.
7-46
S
YSTEMS
C D
IRRUS ESIGN
SR22
P/N 13772-006
Reissue A