When I purchased the EarthX battery I also purchased their battery box. I don’t like the oversized battery box currently on the firewall. It has such a large footprint perpendicular to the airflow that it is certain to alter the airflow negatively.
First I strapped the bottom of the EarthX battery box because it just has a simple tongue of aluminum holding the albeit light battery, it’s not what I would consider robust.
Flush mounted the rivets on the battery side.
The last battery box I made I put hinges on the sides so I could just slide the battery out of the box. I’m doing the same on this battery box. Pull the two vertical hinge pins and the front just flips down. I need to order some steel hinge pin. The lower hinge pin will be fixed in place and the two vertical pins will be safety wired in place. I’m mounting this horizontally and will add a secure velcro strap to secure the top, which will be on the side when mounted on the firewall.