I went through TSA in Boise and SanDiego. My board was on my back, my battery was in my backpack. I took my skateboard off and let it go trough the detector, i took my laptop out of my backpack, yet my battery stayed in bag.
Both TSA locations asked about my board and said it was really cool. They did NOT touch my backpack nor ask about the 10s3p pack that was in it.