I haven't tried going all the way to -1, but this:
is definitely true.
Went down from 45 (yes, starts at 45) to 33, 24, 18, 13, 9, 6, 4 in testing (possible followed by 3, 2, 1, 0. Always displayed 1 second less than full when it started so -1 at 0 could make sense). So that's a
lot of turns, might be a nice suggestion to limit the turn limit to 5 or 10 seconds, not much you can do in less, even if you wanted to x)