4 Hours of active use! Are you kidding me? Who it their right mind, knowing they would have to remove this thing from their wrist after 4 hours just to charge it up again, would ever use it? Hasn't Apple learned anything about the sealed battery on the iphones? Oh, that's right, they like this as it adds to the market place for 3rd party chargers and portable power storage devices. This is just one more bad flaw in the latest hardware/design from Apple which in my opinion, is going the wrong direction--ever since Steve Jobs has passed away.
http://9to5mac.com/2015/01/22/apple-targets-for-apple-watch-battery-life-revealed-a5-caliber-cpu-inside/