LiPo batteries for Turnigy 9X and Turnigy 9XR transmitters
Turnigy 9X transmitter has holder for 8 batteries of AA size. This holder can be unplugged and frees up space to install the lithium-polymer battery.
Most modern radio transmitters, including Turnigy 9X, designed for 12 V power supply, which is provided by the 8th AA batteries connected in series. 3 cells LiPol battery (3S) provides a slightly lower voltage - 11.1 V, but for most transmitters available on the market this is more than enough. Also most of modern transmitters already designed to work with LiPo batteries and often can control the battery current voltage to prevent full discharge. Remember that LiPo batteries might be damaged by full discharge (do not discharge less than 3.0 V per cell).
If you use a transmitter that does not have discharge control function (eg Turnigy 9X with standard firmware), you will have to constantly check the battery voltage to make sure battery is not discharged below the low voltage limit.
For the new radio transmitter released recently as Turnigy 9XR, HobbyKing also released a special battery that has a built-in discharge protection. Several users have already confirmed that this battery unfortunately doesn’t fit into Turnigy 9X, because of bigger dimensions. If you ordered Turnigy 9XR already, check out battery for it on the HK site.
HobbyKing sells many others LiPo batteries intended to use in radio transmitters. Remember that the usual 3 cell LiPo batteries which you use to power your model airplanes or helicopters, can not be used for transmitters! This is due to the fact that the current Amps level of such batteries is very high (5C - 20C or more), which can burn the transmitter electronics. There are batteries for transmitters with low current, usually from 1C to 3C.
For Turnigy 9X I use battery Rhino 2620mAh 3S 11.1v Low-Discharge Transmitter Lipoly Pack. It perfectly fits the batteries bloc of the transmitter. The cons of the battery is that it has connectors for Futaba and JR transmitters, but not for the Turnigy 9X.
The latter uses a balance connector 2S JST-XH. But the good news is that the connector for Futaba can fit into JST-XH, but you need to be careful with polarity.
Here is how to connect the battery
1. Remove the 8 AA battery holder. Use tweezers as necessary. Also remember position of red and black wires before disconnecting.
2. Connect battery Rhino, using Futaba connector, but control the polarity: the red and black wires should go to the same contacts as it was before.
That's it - the transmitter is ready for use with LiPo battery. If you have some soldering skill, I would recommend replacing one of the connectors with a 2S JST-XH, to make sure you always connect battery safely.
One more note, the standard firmware for Turnigy 9X doesn’t have low discharge alert feature. You will have to monitor voltage on the screen. Another option is to flash the transmitter with an alternative firmware that has such function.