It is my understanding that the battery on the Evo will last approx 12 hours. For normal usage that is fine (for me) but when i travel I tend to use the phone more (watch movie on the planes, browse at the airport and stuff like that) so I doubt the battery would last the full day. As this is during travel charging is not much of an option so what options are there for a second or larger battery (in some other thread it is said to avoid the seido batteries so are there other options?)