Spektrum SPMAR9020 - Manual (Page 11)

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4. If control issues exist, call the Horizon Product Support office.
Receiver Power System Requirements
Inadequate power systems that do not provide the necessary minimum voltage to
the receiver during flight are the number one cause of in-flight failures. Some of
the power system components that affect the ability to properly deliver adequate
power include:
• Receiver battery pack (number of cells, capacity, cell type, state of charge)
• The ESC’s capability to deliver current to the receiver in electric aircraft
• The switch harness, battery leads, servo leads, regulators etc.
The AR9020 has a minimum operational voltage of 3.5 volts; it is highly recommended
the power system be tested per the guidelines below.
Recommended Power System Test Guidelines
If a questionable power system is being used (e.g., a small or old battery, an ESC that
may not have a BEC that will support high-current draw, etc.), perform the following
test with a voltmeter. The Hangar 9 ® Digital Servo & Rx Current Meter (HAN172) or the
Spektrum Flight Log (SPM9540) work well for this test.
Plug the voltmeter into an open channel port in the receiver and with the system on, load
the control surfaces (apply pressure with your hand) while monitoring the voltage at the
receiver. The voltage should remain above 4.8 volts even when all servos are heavily
loaded.
CAUTON: When charging Ni-MH batteries, make sure the battery fully charges.
Ni-MH batteries charged with peak detection fast chargers have a tendency to
false peak (i.e. not fully charge), which could lead to a crash.
QuickConnect™ With Brownout Detection (DSM2 Only)
Your AR9020 features QuickConnect with Brownout Detection.
• Should an interruption of power occur (brownout), the system will reconnect
immediately when power is restored (QuickConnect).
• The LED on the receiver will flash slowly, indicating a power interruption
(brownout) has occurred.
• Brownouts can be caused by an inadequate power supply (weak battery or
regulator), a loose connector, a bad switch, an inadequate BEC when using an
Electronic speed controller, etc.
• Brownouts occur when the receiver voltage drops below 3.5 volts, thus interrup-
ting control as the servos and receiver require a minimum of 3.5 volts to operate.
How QuickConnect With Brownout Detection Works
• When the receiver voltage drops below 3.5 volts, the system drops out (ceases
to operate).
• When power is restored, the receiver immediately attempts to reconnect to the
last two frequencies it was connected to.
• If the two frequencies are present (the transmitter was left on), the system
reconnects typically in about 4/100 of a second.
QuickConnect with Brownout Detection is designed to allow you to fly safely through
most short duration power interruptions. However, you must correct the cause of these
interruptions before your next flight to prevent a crash.