I bought one of the $6 extended batteries for my EVO on amazon. I rooted and deleted the batterystats.bin file and used my phone. The battery life seemed pretty good for awhile, and then, one night, I went to sleep at like 50% and woke up to a dead phone. I assumed that something had gone wrong...so I investigated some. I noticed that Android OS had over 40% use or somehting like that, which seemed odd to me. I deleted the battery stats and decided to start over on training my phone. I got at least 24 hours on the first charge after doing this which is what I was looking for. It dropped off sharply at the end...I figured it would as it learned the new battery...the steep drop off wasn't a concern for me...as I got 24 hours out of the phone, and Android OS was a mere 2%. Great...I thought to myself. On the second charge up after resetting battery stats, I got about 24 hours again on the battery. Again, it had a sharp fall near the end of its life (I figured it's still learning this battery). However last night, I was over 50% and it was dead again this morning. This behavior is however different. Yes, it died sharply...but the volume of the death is what bothers me. During the second discharge cycle, I went to bed at 15% and woke up at 9%. It only used 6% overnight...so while it was still a sharp drop on the graph...it wasn't a fast drop. Last night was super fast. The Android OS usage isn't even displayed...so it's like 1% or something. I have all sorts of screen shots over the course of this experience, but I didn't want to fill this thread with images from the start. I can try to arrange them in proper order and make sense out of them if anyone is interested in helping me learn what the heck is happening to my phone.