After 12 months of ownership I still haven't quite fathomed out the requisite conditions under which i-stop is supposed to work.
I generally travel distances of no shorter than 30km so the battery always remains pretty much topped up. That said, when I fire the engine up in our underground garage the blue light illuminates 99.9% of the time and it revs up like fury. OK that's fine - the engine is still warming up. However, I then reverse out of my parking bay and drive up a short ramp before exiting the garage and meeting the road ahead where I then am obliged to stop.
And here's the crux - if I forget to turn off i-stop, which I normally do by habit but occasionally forget, then when stopped at the top of the ramp i-stop cuts in. So, a starting charge has been taken out of the battery, the blue light is still illuminated indicating cold conditions, the A/C is running but still the i-stop function operates. I am forced to ask myself then, exactly what conditions have to be met because everything that I have been led to believe has now been shot down in flames. In fairness though, it doesn't disturb me all that much because I am of the opinion that this function is yet another gimmick (yes I know others have differing opinions which I respect) and turn the blessed thing off more often than not.