You need to input each cells value in mah that you have measured. The results will make your pack with your available cells "as even" as possible as we know groups of cells acts as one. Why use this. If one cell group is 10ah in your 13s pack after you and the rest sits at 11ah. Then the pack will act as its weakest cell group. By using the program you will get a better battery with the cells you've got.
13s 48v pack is usually build by 4 or 5 in each group or specified as 13x4p (=52 cells), 13x5p (=65 cells in total)
Try these to se an example: Copy and paste.
13s4p
2500, 2502, 2555, 2645, 2345, 2456, 2365, 2655, 2467, 2599, 2588, 2744, 2500, 2500, 2502, 2555, 2645, 2345, 2456, 2365, 2655, 2467, 2599, 2588, 2744, 2500, 2500, 2502, 2555, 2645, 2345, 2456, 2365, 2655, 2467, 2599, 2588, 2744, 2500, 2500, 2502, 2555, 2645, 2345, 2456, 2365, 2655, 2467, 2599, 2588, 2744, 2500
13s5p
2500, 2502, 2555, 2645, 2345, 2456, 2365, 2655, 2467, 2599, 2588, 2744, 2500, 2500, 2502, 2555, 2645, 2345, 2456, 2365, 2655, 2467, 2599, 2588, 2744, 2500, 2500, 2502, 2555, 2645, 2345, 2456, 2365, 2655, 2467, 2599, 2588, 2744, 2500, 2500, 2502, 2555, 2645, 2345, 2456, 2365, 2655, 2467, 2599, 2588, 2744, 2500, 2500, 2502, 2555, 2645, 2345, 2456, 2365, 2655, 2467, 2599, 2588, 2744, 2500