The disclosure features power transmitting apparatus for wireless power transfer to a receiver that includes a housing having a form factor that corresponds to a container featuring lateral surfaces, a bottom surface, and an opening opposite the bottom surface, a first coil formed by a continuous path of electrically conductive material and featuring a plurality of non-planar loops that conform to a first pair of opposite lateral surfaces and to the bottom surface, and a second coil formed by a continuous path of electrically conductive material and featuring a plurality of non-planar loops that conform to a second pair of opposite lateral surfaces and to the bottom surface.