Does battery calibration calibrate the phone or the battery. I have two 1750 batteries - both about a month old. I calibrated both when I got them. But a couple of days ago, one started going down to 80 percent faster than the other after an overnight charge on a wall charger where the light was green for hours. On the other battery I have always taken it off charge as soon as the light turns green. I still get pretty good life but not as good as the other battery (24 vs 29 hrs). If I recalibrate the one that discharges faster, does it just change the phone reading and the other battery will act different or does it actually calibrate the battery itself? I'm not sure exactly what battery calibration does.