User Manual

LiFe (Lithium-Iron)
A very inexpensive 3s 1500 mAh LiFe battery specifically for transmitters is available. LiFe
batteries are safer than LiPo but still need proper handling. For example, if allowed to discharge
fully (by leaving the transmitter turned on) they will be damaged and not be rechargeable in the
normal way. Instructions for recovery can be found online but seldom work more than once with a
given battery. The typical maximum charge voltage is 10.8 volts, but the battery settles back to 9.9
volts within the first few minutes of use and declines very slowly over the discharge. Of the three
leads on the battery, only the balance lead will fit the 9XR. It is recommended to set the low
voltage alarm at 9.3 volts. At the recommended rate of 1.5A, charging will take about an hour.
The battery must be charged out of the transmitter with a charger specifically designed for
LiFe/A123 type batteries. Charging with a NiMH or NiCd charger will probably destroy the battery.
NiMH
AA-size NiMh cells can be made up into a reliable, safe pack suitable for air travel. Low self-
discharge (LSD) should be used. For the 9XR, a six-cell pack is the largest that will fit in the battery
compartment. You will need to fit a JST-XH 4 pin balance lead connector (only the outer wires are
used). The battery will show about 8.5v immediately after charging and can be discharged to a
safe minimum of about 6.6v. Hence such a pack is well within the 9XR voltage limits. The battery
may be charged whilst installed in the radio but the charger used must deliver less than 0.3 Amps
(300 mA) at 12 volts. If the battery is almost fully discharged and a typical 150 mA charger is used,
charging may take up to 24 hours. Higher charging rates may be used with the battery removed
from the radio using an intelligent peak-detect charger on the NiMh setting. Refer to the charger
manufacturers instructions for the correct method.
It is recommended to set the low voltage alarm to about 7.0 Volts for a 6 cell pack, thus allowing
ample headroom for the transmitter regulators and giving the pilot plenty of time to land.
Li-Ion
Packs of two Li-Ion cells may be used in the 9XR transmitter. Cells are available with built in
regulators. Capacity varies from 800 to 3200 mAh for the same physical dimensions (the capacity
is usually overstated). Typical specifications for an Ultrafire 18650 3200 mAh Rechargeable
Battery: Length 67 mm, Diameter 11 mm.
The regulator limits the charge current to 1.5 Amps, so charging time will be around two hours for a
near-empty 3200 mAh pack. Care must be taken when soldering leads to the ends of the battery
not to apply too much heat so as not to damage the regulator. You will need to fit a JST-XH 4 pin
balance lead connector (be super careful to get the polarity right!). These cells require the use of a
charger capable of charging Li-Ion cells.
These cells charge to 8.4 volts but quickly assume a consistent delivery at about 7.4 to 7.6 Volts
for most of the discharge. The minimum voltage to avoid battery damage is 6.5 Volts, but it is
recommended to set the low voltage alarm at 7.0 volts to allow ample headroom for the transmitter
regulators (and time to land!).
Battery Related Settings
Calibrating Voltage and Setting the Battery Warning
Before setting the transmitter battery warning you need to calibrate the voltage reading. Measure
the voltage of your battery with a voltmeter while the radio is on and then go to the calibration
page. A long press of the LEFT key will take you from the home pages to a sequence of eleven
radio setup pages. Use LEFT or RIGHT to get to 8/11:
9XR Pro: Introduction to the Hardware: version 1 3