The following string is detected as having a None encoding despite being a valid string in one of chardet's supported encodings:

u'<\xa0'.encode('iso-8859-7')

This remains true even if you pad it with ascii, it's not a length issue.

This behaviour is present in 9e419e9 (I just only was able to find it once #63 was fixed).

Shall I send you a pull request with the test that is finding these? It's not very complicated.