Should I use BEC or UPS module on Jetson TK1 with using 3S LIPO battery..?

I’ll use Jetson TK1 board with my 900mm size hexacopter and 550mm size quadcopter.

hexacopter uses 6S battery and Quad also uses 6S battery

but probably I’ll not use BEC and

directly connect seperated 3S LIPo battery to Jetson TK1 board.

but 3S LIPo battery’s voltage varies 9.0v~12.6v

So I’m worrying about Damaging Jetson board by its unstable voltage.

Do anyone uses 3S LIPo battery with Jetson TK1 board…?

is it okay to use LIPo battery directly connected Despite of its unstable voltage…?

9~12.6V is for TK1 input. Since you are using battery, why the voltage is unstable?