I just received a new Zippy 2100mAh 2C LiFePo4 battery and charged it at 1 amp with an A123 Nanophosphate charger. When the charger cycle finished, I checked the balance and there was a .2 volt difference between the cells. Is this normal or is it a problem? The last Turnigy LiFePo4 4500 mAh battery I acquired was always well within a .1 volt difference!