I embedded the link in the word "link" and also specified 230 ah cells. They have boxes bigger than what I posted dimensions of. If you need an enclosure for 280 ah I think they have a size that would work.
I apologize... I'm not sure why I thought your cells were 230 AH like the ones I plan on using when you clearly state several times that they are 280 AH. The next size larger in the boxes I am looking at has inside dimensions of 560x520x270. Maybe just barely too big... can't win... :D In that box I think I could build a 48v 230 AH or a 24v 460 AH pack... either way... huge battery that would weigh a tad over 150 pounds.
That's the same issue I'm having the Dimensions I have would be an inside dimension of no less than 572 mm X 174 MM. The widest I saw had an inside dimension of 540, not big enough. So the one you found was a tad bigger.
For weight, I'm coming up with 95 LBS for the cells alone for an 8S 280 ah battery.
This case is turning into taking a lot of time for this project. Was the same way with the vented case for my flooded lead Acid Battery for 4 golf cart batteries. No-one makes vented cases that big so that was about a dozen trips to five different stores with the actual case coming from a plastic manufacturer in Canada.
I wish I'd kept the links. When I was searching for my 572 mm X 174 MM ID box, I saw a few links that looked just like the ones in the above link. One or two had hardware. This may be an example, but I don't see the hardware kits as I did in some.
Replacement Empty Plastic Prismatic Box Ion Lithium Battery Case For 12v 24v 48v 200ah 240ah 280ah Lifepo4 Battery - Buy Lifepo4 Battery Case,Prismatic Battery Case,Lithium Battery Case Product on Alibaba.com
A search for "280 EVE ABS Case 12 Volt 4S" on Ali gives me what looks like a lot of cases like on the first site, but I'm not sure of the minimum purchase quantity, delivery time, etc. If I were to start over, I'd be contacting the seller for a quote and some questions. If I started over now, I'd have to purchase four 12 Volt BMSs and get rid of the two 24 volt I already have.
Besides the $120 case from the solar supply store linked in post #27, the rest of the story is a $30 assembly kit they actually offer:
It would seem to me, and I am new to all of this so I could be wrong, that you could find a way to config your 8s pack in the dimensions I posted... The problem is now its encroaching on the size limit you specified. I'd be tempted to get one and modify it ito fit.