• I just received the one you mentioned, it works great!  I did have to change the connectors though.

  • There is a little confusion about the best 2S vs 3S better battery for the 9X. If conceptually it is true that a bigger dropout voltage between input and output leads in a bigger heat dissipation, the 7805 regulator has been designed to give the best performances with a differential voltage between input and output of about 5 to 10V. With the 7,5V (from 6V depending on the model) minimum input required voltage (2,5V of differential dropout voltage between input and output for 7805) the output peak current can not be achieved (the regulator can´t work at full dynamic range). In fact the factory testings of the LM7805 are done with a typical input voltage of 10V. Following this lines, and assuming that the input regulator is a 78xx, a 3S Lipo battery should be a better candidate than 2S to power the turnigy 9X. You can check the Peak Output Current Vs differential input-output voltage characteristic in the figure of page 21 of the attached datasheet or the Droupout voltage characteristic googleing "7805".

    This explanation does not means that a 2S is a bad option, but in this case the regulator won´t work at full dynamic range of its output current. By the way, looking the datasheets a dropout of 5 to 7V between input and output (corresponding to an input voltage between 10 and 12V) doesn´t lead in a significative amount of heat increase.

    Cheers from Spain.


  • Moderator

    I've got a 3S 1800 mAh lipo in mine, and it works well.


    - snipped the connector from the supplied battery pack

    - soldered a JST connector to this lead.  double check your polarity

    - attach the battery via the JST connector


    I had the junky 3S sitting around.  It came with my Hawk Sky, but I use Zippy 2200s with that plane.  Luckily, it is the perfect size for the battery compartment.


    Voltage drop is less than 0.1V/hour.  I'm careful not to let the battery go under 9V, but that hasn't been a problem so far.

    On the downside, you don't get a beeping warning for low battery, but so far it hasn't been necessary.  I'm not able to detect any heat buildup from the linear voltage regulators.  If I would have had a spare 2S battery I would have used that one, but as I said I had a perfectly size 3S just going to waste.

  • Could this fit?


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  • Look at this form:


    There is a whole discussion on battery options and mods.

  • Thanks @tonyH, @cronselaar and @Simon for the information and specially for the link to rcmodelreviews. Great stuff there!
  • I'm using a HK Zippy 800mAh 2S Lipo - fits just fine.
    You either need to make the change to the two resistors (RCModelreviews ref as before) or, better still, re-flash the software with the er9x code and just change the alarm point.
    This is a great and cheap Tx but with loads of DIY mod options to be found on the web- changing the battery is just the first step.
  • Hi

    I have a 9X and would not suggest that you use the battery you have linked. All the internals work on 5V so giving it the 12V is a total waste and would only be turned to heat. See:
    I used all the instructions on the resistor part except that i'm using a normal 2cell from HK. It does require soldering and cutting off the plug on the old 8xAA battery holder but works really nice.... Using my TX for 1 to 2 months before it needs a recharge. If you need the inside dimensions of the battery bay to get the right battery i'll happily measure mine.

    Kind regards
    A 2400mAH Lithium Transmitter Battery For Just $10
    Fit a 2400mAH battery to your 2.4GHz transmitter for $10
  • I'm not sure if anyone has done it, but some rewiring would have to be done to use a LiPo with the Turnigy 9x. Normally, it uses 8x AA batteries.
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