3. Welding the Battery Box
	I chose to build the box from 5 separate pieces as opposed to bending it up from one. The only reason is that I like the way it looks better when finish welded.
	The box tacked up.
	And the finished beads.
4. Welding the Box to the Tank
	If you don't have a torch to cut the hole out for the box use a cut-off wheel attached to your angle grinder.
	The box is placed into the hole and tacked into place.
5. The Completed Tank
	Here's the completed tank after finish welding the box to the tank and welding in the fittings. The fill tube is 1" pipe with a hex cap.
	Top and bottom mounts are 5/16" 18, "T-style" weld nuts.
	Feed, return and vent fittings are 1/4" NPT bushings. Drain plug is a 1/4" NPT half coupling with plug.
I think the big thing to remember is that there isn't "one way" to do any of this. It's very likely that you'll figure out a way of doing something that works better or faster for you. This is just my way of making this oil tank and that could change tomorrow.