Battery percentage indication on Taranis radio

Hello everyone,

I would like to ask you what cause of battery percentage on the Tx’s screen is always 99% percent. It doesn’t matter the state of charge of the battery. I have read through the github’s yaapu battery configuration, but I don’t know what did I do wrong? Should I need any additional sensor next to the floght controllerIn the mission planner “bat remaining” is 0% but this not important for me at all.
I have 6s 12Ah lipo, Frsky Taranis x9 lite, with opentx 2.3.15 and yaapu script on the radio. The communication is through Fport between Mateksys H743 wlite flight controller and R8 Pro receiver, ardurover 4.2.3 running on it.

Thanks for all.