Here is the battery mounted and the switch bracket. The switch bracket is simply a bent piece of sheet metal. You can see I cut a piece of pipe to use as a spacer to be able to tighten battery mount. You can see the connector from the DPDT switch to the electronics.
DPDT Switch: https://www.amazon.com/Heavy-Handle-Mome...QG5GHM5Z0S
DPDT Switch: https://www.amazon.com/Heavy-Handle-Mome...QG5GHM5Z0S