Battery Vehicle Society

Dear all,
I'm currently mapping out the LIFEPO4 battery pack locations on my donor car and it'll actually be split in two distinct ones : under the bonnet and in the boot. As for the latter, I'd like to keep as much loading room as possible and am therefore thinking about two options:
- trying to fit some batts under the external rear part of the car and some inside the car in the boot and bolting in a cage structure on each side in the metal bottoming the boot for securing the batts (dunno if that's clear ).
- cutting out the boot bottom to fit in a bespoke metal cage for holding the rear battery pack (approx 25 batts). I have a rather clear understanding of where the most solid parts of the chassis are located at the rear end but was just wondering about how chopping off metal from the boot bottom would affect the body's structural strength
I know some converters did this but if any of you had made that irreversible decision, what are the things to consider to do this right?
Thanks

I had a Rover Metro converted by Robert Fowler (aka AVT or "everything ev")
He had made space for a rear battery box by cutting out some of the floor of the boot (this originally had a round well for the spare wheel, and he just cut a rectangular hole a bit bigger than the original well)
I had this for 9 years and there was no obvious loss of structural strength - though fortunately it was never put to the test in a crash.

I put a fairly big tray under the back seat in my old Feista conversion, I didnt even think about body structure just went at it with a plasma cutter and job was a gooden

Although the tray that was welded back in I suspect was far stronger than the bit of metal that I cut out

Cant remember any major problems, although it was done while the car was TOTALLY stripped out and was just a shell, and thus I didnt have to worry about cutting brake lines or electrics etc.

We did from memory have a small fire issue when welding the tray in but that was more due to setting light to the dam body underseal during welding

ChrisB

Thanks guys.

Although the tray that was welded back in I suspect was far stronger than the bit of metal that I cut out

Is there a way (maths or physics) to prove that is the case? If I can't bring evidence of that, I'm bound to be up poop creek for the final approval.

Do you need to

I'd think if they get a bit narky then you could add a couple of bolt on strengthers over the area, but I'd think as long as your not chopping bits out of the chasis then you "should" be fine

ChrisB