Cleaned up the two pieces of angle with MEK and shot with primer. After the primer dried, I squeezed the rivets attaching the angle near the front of the battery, and used the gun to set the rivets on the rear angle. I crimped a terminal lug to a 3 foot section of #2 cable, then heated up the terminal & wire with a torch and ran solder into the joint--added some heat shrink tubing. This end will make the connection to a piece of angle that will be bolted to a longeron near the battery tray. After the battery is installed, I’ll cut the ground cable to length and add another terminal for the battery connection.