My S2 has been very strange in the last two days. I have a big 2000mAH battery. The phone is unrooted. After charging to 100%, both yesterday and today the phone was down to 18% charge in only two hours! This was with the screen off and no use of the phone at all! So today I put in my previous 1650mAH battery. It started at 59% charge and I charged it to 100%. Then once again with screen off and no use of the phone, this battery also discharged down to 19% in two hours!! What the? Is there likely to be something seriously wrong with my phone?- that it is discharging batteries so fast with nothing specifically happening to cause this discharge -of two batteries?