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.
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!
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.
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
- You have to modify your Taranis housing
- Soldering directly on 18650 cells – can be dangerous if you overheat the battery!
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
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
- It requires a 3D printed “special battery cover”
- You can’t use the original battery cover
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.