Friday, September 12, 2008

Upper Rear Rack, I

I found a few spare hours in the early morning / late evening this week to build the first part of the upper rear rack (it will hold 7 batteries). First, I planned it out in Sketchup:
Perspective view:

Exploded, so you can see how all the pieces are shaped and fit together. Would be nice if Sketchup had an "exploded view" option but I can't find it if it does. I prefer this kind of jigsaw-puzzle fitting together for some reason. I justify it by saying I can cut those straight lines more accurately than the diagonals the normal "picture frame" way would require. Also, I can grind the weld beads off closer than I could with the diagonals. But I suspect those are just rationalizations and I simply like the aesthetics of this kind of design:

So, off to the angle grinder and chopsaw I go. Again, I used a flapwheel sander to clean off the paint / grease / rust / etc. from the angle iron, and then chop-sawed them all to the proper lengths (which are written on them with a Sharpie so I can easily tell them apart):

Next, I marked the special cutouts with a Sharpie:

...and then used a cutting wheel on my angle grinder to cut them to shape:

Here is the outer part test-fit to make sure it looks right:

And here it is, all welded together and placed in the rear compartment for visualization and hole-drilling purposes (holes will be drilled through the upper rack and then through the lower rack at the front of the lower rack). My daughter KatC did one of the welds - her first one!

Here is the completed rack with batteries placed in it:

And here is a measurement of the clearance between a battery in the lower rear rack and the bottom of the upper rear rack - roughly 1/2 inch, which allows for 1/4 inch of polypropylene plus another 1/4 inch of spacers on between the batteries and the lid (to make it easier to route the interconnects):

With the upper rear rack assembled and in place, I can finally drill the holes through the lower rack and the body sheet metal. The holes fit 3/8 inch stainless steel bolts. As always, I drilled them progressively (starting with a 1/8 inch bit and moving up by 1/16 inch until I got to 3/8):

I then drilled the holes for the hold-down mounting bolts and welded the bolts in place on the lower rear rack (you can see one of the acorn nuts that will attach the hold-downs rolling around inside the lower rear rack):

With all that drilling and welding complete - it's time for paint! I used the POR-15 treatment again. Here is the outside after the first coat - I will also top-coat with a POR-15 UV-resistant black topcoat for enhanced durability:

And that's it for this week. This weekend, I am at Nan Desu Kan with my daughter again, so I won't make much progress. Short term list of things for next week:

  • Top coat the rear rack exterior
  • Paint and top coat the rear rack interior
  • Permanently attach the rear rack
  • Make a box for the upper rear rack (to prevent fingers / cargo / etc. from getting at high voltage)
  • Paint the upper rear rack and permanently attach it
If time allows, I will design and build the racks / boxes for the two batteries that go under the rear seat. We'll see...

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