I have 2 backup batteries made by TCW Technologies. One is for a backup to the Lightspeed electronic ignition system and the other is for the avionics. With the wiring harness complete and the connectors on the left side I decided to mount the 2 batteries underneath the comm 2 mounting support. I cut 4 pieces of 0.063 x 3/4 x 3/4" aluminum angle stock. The 2 longer angles would be attached to the long comm 2 angles using #8 screws and locknuts. Each long piece has 2 nutplates for #8 screws to attach shorter cross angles and also anchor 1 corner of each battery. The short cross angles also have 2 nutplates each to support the inboard flange of the battery. I marked the location of all the nutplates using the batteries as templates. I drilled, deburred, countersunk and riveted 4 MS21047L08 and 4 MS21051L08 nutplates with AN426AD rivets. I matched drilled the 2 long angles to the comm 2 angles and attached with #8 screws and locknuts.
