Strange "clicking" sound (Aliens?)
church;
My money is on the REAR Belt being too loose. There is a really fine line between being just right and too loose. Just adust the Belt tensioner 1 notch tighter and it should be alright.
For the Battery Packs, use the little pieces of Foam on the sides (as 'newracer' suggested). You can also put a thicker piece under the Battery Strap to help keep them in place.