That seems like a bit much... (do other users have similar experience?) Perhaps it is my heavy usage of tethering while charging? Or is it car charger? Or strange charger from single AA I used long time ago?
HTC Dream has USB connector for charging. Does it mean it should tolerate anything from 0V to 5.5V?
What is worse, the batteries are hard to get in Prague. For a phone that needs so many of them, that's quite surprising.