I fit the battery box to the firewall and drilled the three mounting holes an AN3 bolts. This can’t be installed permanently now since the firewall recess hasn’t been riveted on.
Here’s the battery in the box. I’ve taped off the posts so that I don’t accidentally short anything across the battery.
I fabricated the hold down strap from some aluminum bar stock. This gets held down with a couple of AN3 bolts that run through some spacers I made so that the bolts can be torqued down without putting excessive force on the top of the battery. The battery weighs almost 15lbs, and the plane is rated to handle 3 negative Gs, so the strap needs to handle at least a 45lbs load plus a healthy safety margin.
I also fabricated the firewall stiffener for the center attach points of the two contactors. Since I adjusted the position of the contactors, this also isn’t to plans. I basically just roughly centered the plate horizontally and vertically on the pair of center holes and then laid out four rivets around the perimeter to tie it to the firewall. I didn’t get a picture of it, but I then final drilled/reamed the center holes to 1/4″ and then drilled for nutplates. I want to prime this plate, so I didn’t get it installed tonight. I’ve got a pretty big pile of parts that needs priming how, so I should probably have a priming session in the next few days.
