By default you can only get the total battery voltage with Crossfire telemetry. Here’s an easy trick to get averaged cell voltage from telemetry, so you don’t have to do the math in your head.
In fact Frsky offers this option, it’s the
A4 Telemetry Sensor, however Crossfire doesn’t have this, fortunately there’s a easy work around.
Simply enter this line in Betaflight:
set report_cell_voltage = ON
Then you will get the average cell voltage instead of the total battery voltage from
RxBt sensor. For example if you have a 4S battery with voltage of 16V, RxBt on your radio will now read 4.0V instead of 16V.
This is useful if you have multiple quads that uses different cell count batteries, such as 4S and 6S which can be confusing sometimes.