When securing the LiPo battery use at least two cable ties, or ideally three. There are limits to the thickness of these ties when using the outer shell, so pay careful attention to clearance on the back side of the sled. Ideally the vertical ziptie should be applied first as it can recess an additional 1 mm below the level of the horizontal zipties. A piece of double stick tape between the battery and sled provides extra insurance. Always be sure to properly secure any connections between the battery and tracker so they are supported during flight and recovery.