Because of a motor change (okay, several), I had to relocate the batteries right behind the firewall. I built a tray as shown before. It was meant to be a prototype with a more finished and lighter version to come later, but it worked well enough that I haven't gotten around to building another one yet. There isn't actually a lot of room up there, there is a firewall support between the firewall and the top stringer that gets in the way with batteries. If you lay the batteries on their side, as shown, you can get around this. Not sure where other guys may be in their build, but this was a sticking point early on as to where and how to place the batteries.

Tom M