I removed the battery from the right side of the car and prepared the spot for welding the battery bracket back on.
Safety note: When you have two batteries in parallel, you must be very careful when you disconnect them. Don’t let that positive cable touch ground. The positive (+) cable is hot until you disconnect both positives from both batteries. To be very safe, disconnect the ground cables on both batteries.
Another little safety note from an old submarine sailor: If you have short wrenches that will reach from the positive terminal over the the negative terminal of your battery, use them to do your work on batteries AND tape off the end that you are not using. You don’t want to let that wrench get shorted between the positive (+) post or cable and the negative (-) post or any ground (hold down bolts, battery bracket, fender well, trunk or tail light housing).
I finished welding the bracket and everything is back to normal.