The battery is discharged suddenly on Galaxy S2 Sometimes after I fully charge the phone, and disconnecting it from the power, the battery suddenly drops to 97%, it is normal? I already made a battery calibration past week. Well, this happened only 2 times.
Yes, this is fairly normal. It happens on most new devices, i have an Evo and it does this constantly. If i'm not mistaken, it comes from the fact that there are multiple cells in the battery, and when it reads 100%, they may not all be fully charged. Thus, when the battery discharges, the first few percent goes quickly, because it wasn't actually charged completely to begin with. 

I assume you did something like this for recalibration:


Turn the EVO on and charge it until the LED indicator turns green.
Unplug it and turn it off.
Plug it back in and charge until the LED indicator turns green.
Unplug it and turn it on.
Once powered on completely, turn it off again.
Plug it back in and charge until the LED turns green.
Unplug it, turn it on, and use it normally.


Without this, i find the battery usually drops to 90% pretty quickly, but if yours is only decreasing to 97% in that time, you're probably okay. 

The only thing we can really do is hope that these hit it big soon.