I am new to this forum and this thread, but I am also planning a 8x 280Ah (24V) LiFePO4 battery and after an hour or two drawing possible battery configurations and internal dimensions of various boxes, I have ordered the RSO2415-9 box and the LID2415 to go with it. It can support 150 pounds and I guess it is designed for warehouse / industrial uses. I haven't received it yet. I was also considering some "diamond plate" truck-bed / ATV boxes but decided to go with this plastic box instead.