Fitting the battery boxes^3h

I got two battery boxes from EarthX and fitted them to the forward structure.

The idea I have is to put both of the battery boxes behind the firewall, away from the heat of the engine compartment. To do that, I chose two bays on both sides of the central rib.

The first issue I encountered was that my mock EarthX case "E" boxes did not fit the box. I asked on VAF and EarthX answered that they made the battery a bit smaller a few years ago (presumably so it has the same size as a "standard" Odyssey PC680).

Then, I mocked my setup with some angles.

I wasn't entirely happy about the setup. It looks a little too heavy, but I couldn't think of a better idea. Another issue, which I only realized later, is that in this position a battery will rest on two points only: one being the part of the case sitting on top of the firewall stiffener (solid and robust), and the other being the clamp that will hold the battery—a questionable setup. I asked EarthX support if that orientation is okay for their BB-MU2 Lightweight Aluminum Battery Box, and they said it is fine. However, it would still only rely on two fasteners to hold about half (?) of the weight of the battery.

I also considered a slightly different setup with angles bent to attach to the central rib, but rejected that idea.

Then, I drilled all the parts to the structure.

To drill the five holes that attach a battery box to the forward stiffeners, I used #40 angle drills, then upsized them from below with a 12" long #30 drill bit.

However, once I removed the box, I realized that I had drilled an "extra" hole in the stiffener!

I asked builder support, and they suggested putting a doubler there. However, since there will be a box on top of that stiffener, I thought I didn't have space for a doubler (for some reason, I didn't think of the box itself as a doubler).

Instead, I decided to replace the whole stiffener. Manual Section 4 listed F-601L as AA6-125X3/4X3/4, which is just a regular 1/8" thick 3/4" by 3/4" angle (the same as used for the longerons).