The 48v/ 17.5Ah battery case is probably set-up for (13) x(5) = 65 batteries, probably 18650 cells would be my guess.
To see if a 52v 17Ah case would work do this.
Get some penny’s and some nickels, like 100 of each.
The diameter of a penny is about the size of an 18650 cell, the diameter of a...