@ecabanas In many cases, it's actually not necessary to send floats. Either just convert to integers (if the decimal part is not useful), or multiply by a power of 10 before doing so. Adding an offset may also help
For instance, if you have values between 0.00 and 2.00 and need 2 decimals, then multiply by 100, you'll get an integer between 0 and 200 which you can encode as a single byte.
If you have values between 20.0 and 40.0 and only need one decimal, subtract 20 and multiply by 10, you'll again be able to send that as a single byte.
Given the limitations of Sigfox packet sizes, every byte (and even every bit) counts! Don't waste bits on precision or exponents you don't need. Try to find out for each value the possible range and how much precision you need, and use the smallest number of bits which can accommodate that.