Mini-X Installation, Setup & User Manual GRT Avionics
Revision A9 94
A.2 Backup Battery Operation
The backup battery option allows the Mini to operate from an internal user-replaceable Li-ion
battery when external power is lost. The battery is charged automatically when the instrument is
provided with aircraft power. The battery support circuit is designed with a variety of safeguards
to prevent over-charging, charging at excessive temperatures, excessive discharge, and other
abnormal conditions. The battery is enclosed within the aluminum housing to provide additional
safety.
Operation from the internal battery is completely automatic. Once powered up using aircraft power,
the Mini will automatically switch to its internal battery if aircraft power is lost without any
interruption (no re-booting). If this occurs when the airspeed and GPS data indicate the Mini is on
the ground, the pilot will be prompted to continue operation from the battery. No pilot action is
required if power loss occurs in flight.
The Mini can not be powered-up without external power. This prevents the internal battery from
being discharged by an inadvertently turning the Mini on when exiting from the airplane.
When operating from battery power, the Mini may be turned off by pressing the right knob, and
following the on-screen instructions, or by pressing and holding the knob for more than 5 seconds.
Charging and Battery State Indication
The battery icon in the upper right portion of the screen indicates the state of charge of the battery,
and the presence or absence of external electrical power. The approximate state of charge is
indicated by the portion of the battery that is green. A lightning bolt is shown in the battery icon
when external power is provided to the Mini.
The Mini is designed to maximize the life of the battery and the reliability of the backup power.
The design prevents the battery from being excessively discharged, even if the instrument is left
on until the battery operation ends. Similarly, charging terminates automatically at a level that
maximizes battery life.
Caution: If safe flight in the event of an aircraft electrical failure requires operation from the Mini's
internal battery, be aware of the state of charge of the battery, and do not takeoff into IFR
conditions with a discharged battery. Battery life is shortened at low temperatures and with aging
of the battery, such that it is prudent to expect battery life reduced by as much as 50%.
Maintenance
The Mini should be discharged on an annual basis and the operating time and ambient temperature
recorded in the airplane log book. Discharge should occur at maximum screen brightness.