I got a new GoPro Hero 2 last week. This weekend on the Etowah, it died about 2.5 hours later before finishing the river (yes, I fully charged it first). I left it powered on the whole 2.5 hours, but only recorded about 30 minutes of the 2.5 hours. Should I power it on/off every time I record to save the battery. Does anyone use the one button mode to do this? BTW, other than the weak battery, I love the GoPro. It shoots great video.