Blog / Battery clamp added in 3D drawing
Here's what I had in mind to hold the batteries in place and it's also for attaching the cover. There will be rivet nuts in all of the holes and everything will be fastened from the outside this way.
Don't know if the triangular shapes are necessary but it should be sturdier that way.
Here it's in the battery box.
Might have to add something else in the middle of this battery box though since there are 2 rows of batteries in it. The other battery boxes will all have 1 row so it should be easier for those.