our application may be bit different than yours. Ground battery through trunk to frame. Then ran ground through passenger compartment to firewall stud. Ran power through switch, through passenger compartment up to firewall stud.
Needed room for fuel cell. So battery box (from Summit) is "slightly" wedged under trunk edge. But clears trunk lid and mechanism. Bolted down through trunk.
It's all wired now. This pic is when we fitted it.
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