Taranis X9D-Plus 18650 Battery Mod

The Taranis X9D Plus radio transmitter takes 2S LiPo or Li-Ion battery. 18650 Li-Ion cells would have been an obvious option given the excellent capacity to weight ratio. However they don’t fit the Taranis battery compartment without some modifications.

Here I will show you a couple of ways to install two 18650 batteries in the Taranis X9D-Plus :) Check out this article for more Taranis X9D hacks, tutorials and tips.

My Choice of 18650 Li-Ion Cells

After some testing, I found these 18650 cells (3400mAh) to be excellent for FPV equipment:

Using two of these cells gives you 70% more battery life than the original 2000mAh NiMH battery, and it only weighs 93g!

#1 – Removing Plastic In Taranis Housing

The easiest method to fit a 2S 18650 battery in the Taranis X9D, is by cutting away the plastic struts in the middle of battery bay.

Parts Used

How to Build 2S 18650 Battery

How to solder 18650 batteries properly is beyond the scope of this tutorial, please do your own research.

Here is the basic wiring, by connecting the two 1S cells in serial you get a 2S battery.

First off, roughen up the contact surfaces on the cells, then tin them with solder.

Solder the negative of cell #1 to the positive of cell #2, and also the middle wire of the balance lead to either side.

Solder the positive wires of both the discharge lead and balance lead to the positive of cell #1, and the negative wires to the negative of cell #2.

Finally, cover the solder joints with electrical tape. It’s going to be an extremely tight fit in the battery bay, so you have to make sure the wrapping is as thin as possible.

I finished mine with PVC heatshrink, looking really neat! (hair dyer works great). You don’t have to use heatshrink, but if you do, stick with PVC type, the rubber type would probably be too thick!

Don’t forget to change “Battery meter range” to “6.0 – 8.4” in Radio Setup (hold down Menu button).

Advantages of this mod:

  • Cheap and easy
  • You get to keep using the original battery cover

Downsides:

  • You have to modify your Taranis housing
  • Soldering directly on 18650 cells – can be dangerous if you overheat the battery!

#2 – 3D Printed Battery Cover

Initially, I was going to end this mod/tutorial with method #1. But to take care of  people who don’t want to solder directly on 18650 batteries, I decided to spend some more time to create a “safer method”.

I designed a 3D printed cover for the battery compartment, which has an extrusion in the middle to accommodate for a two-cell 18650 battery holder. You can download the STL file here: https://www.thingiverse.com/thing:3411863

Parts Used

Soldering Wires to Battery Holder

This is how to wire balance lead to the battery holder.

Installing 2S 18650 battery holder in the battery bay.

With the 3D printed battery cover.

Advantages of using 2S battery holder:

  • Safer – no soldering on battery
  • 18650 cells are removable, you can share cells between Fatshark goggles, much more flexible!
  • No need to mod your Taranis

Downsides:

  • It requires a 3D printed “special battery cover”
  • You can’t use the original battery cover

Too Much Hassle? Just Get a LiPo

I recently tested a 2S LiPo designed specifically for the Taranis. It’s a “okay-ish” replacement for the original NiMH battery in my opinion. The  good thing is there is no DIY involved.

20 thoughts on “Taranis X9D-Plus 18650 Battery Mod

  1. Allen

    banggood.com/18650-Battery-Cover-for-Frsky-Taranis-X9D-X9D-Plus-Radio-Transmitter-p-1435553.html?ID=224&cur_warehouse=CN

    will this fit using the battery holder?

    Reply
    1. Oscar Post author

      Well, it’s a clone of my holder so it should. But if they cloned my first version it might not fit (very very tight fit anyway). I made it deeper in the second version.

      Reply
  2. Spem Menot

    What do you think of Li-Ion 18500 batteries? The 500s are shorter so would fit the bay in series. the only down side is they seem to stop at 2000 mAh.
    I’ve just ordered a Taranis SE 2019 and the notice states Li-batteries but not LiFe. I’m leery to have LiPos in my transmitters as I”ve always used LiFe for safety.

    Reply
  3. AnachistFPV

    how about make an 18500 2s2p pack, not sure of how to make balance on that kind of setup, ok i got heeps of 18650s in the range of 10-30Amp constant draw so i can make 2s1p packs to my R9m and my x9d+ but like to run my R9m from internal power to keep wait down, and i call it safe to put range of 18650s in 2s to 5.5-8,4v(2.5v its bit low but dont harm good low Amp 18650s) and if your in Eu don´t buy Ebay 18650s Nkon.nl is best source to genuine cells in Eu, don not trust random Ebay sellers, copy’s are hard to spot(today they even copy the machining on the bare cells under the wraps!), and unicorns DO NOT EXIST so do never ever by any cells calming more mha then Sony/LG/Sanyo/Panasonic list!
    If you like me like your cells last long time, charge them to 4,05 and lifespan will double, at 4,25v you ill cut the lifespan in half, and don´t charge 18650s at a paste higher then recommended by the producer, 1c is not always safe, i like to play it safe so charge rate is at 0.5c, some chemistry explode and some “just” vents.
    Love your work Oscar!
    Hope you appreciate the added info in this mater.

    Reply
  4. Markus Grocholewski

    Hi Oscar,

    I used to buy this battery holder:
    rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.de%2Fulk%2Fitm%2F222837754388

    Obviously, the dimensions of the holder are the same as those of the one, you posted.
    The problem is, that the 3d printed cover is not fitting. Is it my fault? What did I do wrong?

    Reply
  5. Tor Inge B Flatnes

    Hello.
    I have always used your guidelines if I have been firmly locked in any of my projects. But a question here, the batteries are without Bms right? do you not need bms protection on the cells? can I use the owner unprotected and protected?

    Thanks in advance for the replay and to keep us well updated on good rc media work!

    I love it! :) chears.

    Reply
    1. Oscar Post author

      I am using the unprotected cells. I am not sure about protected ones as they are longer, might or might not fit in the bay.

      Reply
  6. Enrico

    nice but i would like to understand better
    1) normal connection to taranis has only + and – With this mod what is the need of the middle pin?
    2) i thought the balance lead should have been used for charging?
    3) what is the purpose of the “discharge line”? is that one the charging port?

    Reply
    1. Oscar Post author

      1) for balance charging
      2) the power plug in the Taranis takes balance connector
      3) for charging, or for other devices other than the Taranis in emergency situations

      Reply
  7. Arne Petry

    Hi Oscar, great article as always!
    As a safer & better fitting alternative you could use 6x 14500 LiFe cells in a 2S/3P configuration and the same size as the original battery pack. Ok, more soldering, slightly more expensive and less capacity, but still :)

    Reply
  8. Benoit Rousselle

    Great post !
    Do you think this is enough to power up the full crossfire TX up to 2W ?
    That way no extra lipo needed to fly full power :D

    Thanks,
    Benoit.

    Reply
  9. Mark Pfeifer

    I use the Turnigy Nano-Tech 1500mah LIFE 3S 9.9V pack with my Taranis X9Dplus. I get 3 weeks between having to take it out to charge. No problems with excess voltage when flashing the RX. Plug and play.

    hobbyking.com/en_us/turnigy-nano-tech-1500mah-life-3s-9-9v-transmitter-pack-taranis-compatible-1.html

    Reply

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