Hole in fender under battery tray

I bet 95% of all the cars I have restored over the decades had rusted out metal under the battery tray. Just the nature of it all, battery acid, moisture trapped under the tray. I always cut out the rust and weld in a patch. It all gets epoxy primer and topcoat in the end. If you aren't a great welder, so what, it will be under the tray!! Drill a drain hole there if you want.