Abstract: The present invention provides an improved battery housing which is a disk shaped cylinder. The inside of the disk is open to allow the cylindrical shaped battery to be mounted on an axle in a flywheel. The housing includes a number pie-slice shaped cells for the individual cells of the battery. A number of these battery housings can be connected together on a single axle, and electrically connected in parallel. Each housing has a negative post and a positive post extending outward which will mate with a corresponding cavity in the next cylindrical battery casing. In addition, there are a number of holes extending through each casing near the outer wall so that rods can be passed through to secure multiple battery casings together.