Performing arithmetic on floating point values of different sizes
I'm guessing that mmin and current and mmax are strings. In which case, this expression:
if mmin <= current <= mmax and 0 <= capacity <= 100:... Is doing a lexicographical comparison on the values. This is different from a numerical comparison: for example, "5000" < "10000" evaluates to False because "5" is larger than "1".
Convert your values to numbers before doing comparisons on them.
if mmax.isdigit() and mmin.isdigit() and current.isdigit(): mmax = float(mmax) current = float(current) mmin = float(mmin) capacity = float(100 * ... #etcOr
if float(mmin) <= float(current) <= float(mmax) and 0 <= capacity <= 100: