My iPhone 6 Plus tears through battery pretty fast compared to recent phone like my Note 3 or LG G3. I'd say about half as good so far. I could regularly go 24 hours without having to charge these devices - sometimes 36 hours - however the iPhone 6 Plus is more like 12 hours. One thing I am curious about is it appears a difference betwen Android and iOS WiFi calling is my Android devices actually disable the LTE modem. However, on iOS I still see the signal moving between 1-2 bars, etc. It replaces LTE/4G with WiFi, but the bars aren't "disabled" like they are on Android. Does iOS not disable this? More importantly are there not any power savings advantage to WiFi calling if so? Where I live / work, the T-Mobile signal can be weak and rotate between Edge, 4G, and 4G LTE...it seems to me the low signal is the only thing that could be draining the battery so much as otherwise my usage characteristics have been similar to the above devices.