New MMM field programming cards

[kvrc]

I have a question for someone from castle. After reading the instructions shown on the back of the device it appears in some cases you need a separate power source for some applications.
I have a mamba max in a 1/8 buggy with 4s and a bec. Will I be able to just plug in the battery like normal and plug in the usb plug and make adjustments or will I need a seperate power source since I use a bec?