Eclipse 500 System Manual page 245

Section 10. Electrical
SYSTEMS BATTERY
During normal operation, the systems battery is connected to the left side of the
electrical system through the battery bus and battery bus contactor. During engine
start, the forward buses are automatically disconnected from the aft buses so that the
systems battery powers the avionics and avoids exposing the battery to the voltage
drop caused by high starting currents.
START BATTERY
During normal operation, the start battery is connected to the right electrical buses
through the start battery contactor. The start battery is also connected to the hot
battery bus, which supplies power for equipment that must be operated before either
battery switch is turned ON.
The start battery supplies power for engine starting either by itself, or in parallel with
external power if it is connected. With one engine running, the start battery supplies
power in parallel with the generator to start the second engine.
BATTERY HEATER PAD
To assure a 30 minute minimum life, a heated battery pad is installed under each
battery. Each battery heating pad contains a 300-Watt heater element, an embedded
thermistor, and a 100°C cut-off. The operational point of each thermal switch is 104
degrees C (rising) and 93 degrees C (falling). The Left ACS is responsible for
monitoring temperatures in the heater pads and forwarding it to the Right ACS. Both
ACSs turn on power to the battery heater when the Outside Air Temperature falls
below 10 degrees C and the aircraft is powered by generator or GPU power. The
ACSs turn the heaters off when the temperature as sensed by the temperature
sensor rises to 80 degrees C, and on, when it falls to 70 degrees C.
Failure of a battery heater pad could shorten battery-only operation time to less than
30 min. If a battery heater pad fails, it is indicated on the ground only with the
appearance of a BATT HEATER FAIL advisory message.
10.5.4 External Power
A 28 volt DC external power receptacle is located on the lower right aft fuselage.
External power automatically powers the airplane when both battery switches are
turned on and the power is the correct polarity and the voltage.
EXTERNAL POWER CONTACTOR
The External Power Contactor automatically closes if the following conditions are
met:
Neither starter/generator is online.
External power is the correct polarity and voltage is between 24 and 29 volts.
Both battery switches are on.
Having both batteries online with external power minimizes the possibility of electrical
noise from the external power source affecting airplane equipment.
The external power contactor automatically opens if the polarity is wrong or if any of
the following occur:
Greater than 29 volts at any time
Aircraft current draw greater than 400A
External Power current draw from aircraft greater than 5 A
Less than 24 volts for longer than 45 seconds
Version 2.0 April 2007
Copyright © — Eclipse Aviation Corporation
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