Low Voltage alarm on Taranis for 3S and 4S

June 13, 2017 - Blog, Tech
Low Voltage alarm on Taranis for 3S and 4S

There are a lot of tutorials out there and I cant’t remember whom to give credit. This is not completely my idea and it just stays here for my own reference. A prerequisite is working telemetry and voltage sensors in the FC.

This is my approach to get an additional low voltage warning on the Taranis with auto detecting 3S and 4S batteries. If the quad is offline, the telemetry reading would be 0 Volts. In order to not play warnings there is a check if there is a battery at all (L21)

If the voltage is critical, the sounds for warnings AND critical will be played.

I use the companion app to edit the configuration on my computer – this is less tedious than using the menu on the Taranis itself. I addition it has got a simulator allowing you to change telemetry as well, so you can play with it.

I am using logical switches and special functions to accomplish the task.

Logical switches

The setup for the voltage alarm starts at L20 in order to keep the parts together so it can be shared between multiple setups and to have some space for individual stuff on top of the list.

Taranis Logical Switches page 1

Here the same setup as text:

L20    a>x    VFAS    12.70V    ---    ---    ---
L21    a>x    VFAS    10.00V    ---    ---    ---
L22    a<x    VFAS    11.01V    !L20   ---    ---
L23    a<x    VFAS    11.71V    !L20   ---    ---
L24    a<x    VFAS    15.01V    L20    ---    ---
L25    a<x    VFAS    15.61V    L20    ---    ---
L26    OR     L22     L24       L21    ---    2.0
L27    OR     L23     L25       L21    ---    2.0



Special functions

Now I can use the values to set up audible / haptic alerts via special functions:

Taranis Special Functions

Again staring at 20:

SF20    L27    Play Value     VFAS      5s
SF21    L27    Play Track     batlow    5s
SF22    L26    Play Sound     Siren     1x
SF23    L26    Play Track     batcrit   5s
SF24    L26    Haptic         2         5s


2 thoughts on “Low Voltage alarm on Taranis for 3S and 4S


You! Are a Saint!! Many thanks to your great and detailed instruction. I fine tuned it for 2s n 3s. Could not have done it’s the way I wanted it without your help! Again thank you. Greetings from Amsterdam



aren’t these thresholds rather high? I programmed my Taranis X7 to read out the battery voltage every 4 seconds when VFAS < 14.4 V (3.6 V / cell for 4s battery) for longer than 2.5 seconds. When the readout activates for the first time it is usually only one readout because after throttle down the battery still recovers. Only after some more flying the battery voltage stays below 14.4 V and then there is a readout every 4 seconds. Then I still fly on low throttle until around 3.2 or 3.1 V per cell. It is perfectly OK to discharge the LiPo until close to 3.00 V. After all, most chargers when measuring the capacity discharge the LiPos until 3.00 V per cell.


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