But 2200 on this phone will still not last as long as the RAZR MAXX HD with its 3200 battery right? Or is the phone that much more efficient than the RMHD?
The RAZR MAXX HD has a 3,300 mAh battery, and yes that is much bigger than this is expected to have, but we have to assume it is going to be FAR more energy efficient than last year's models. The most we can do to appropriately guesstimate (which is an actual word according to Google Chrome's spell check) the battery life on the Moto X is to mathematically determine it based on the rated battery life stats given by Motorola.
The Droid MAXX (2013) has a rated battery life of 48 hours (typical use, which I assume is the basis used for all of their battery stats). That means the 3,500 mAh battery can run the phone for 48 hours. 3,500 / 48 = 72.917 so
theoretically, it takes about 73 mAh (rounded to two sig figs) to power the Droid MAXX for an hour.
The Droid Ultra, with similar specs but a smaller battery has a rated battery life of 28 hours. So 2,130 / 28 = 76.071, it
theoretically takes about 76 mAh to power the Ultra for an hour. Since the MAXX and the Ultra contain essentially the same specs with only a few, practically negligible differences, it's probably safe to assume that the power consumption should be very similar, so the difference in numbers here are due most likely to Motorola's rough estimations. In an attempt to be fair, we will average these results. 76.071 + 72.917 = 148.988. 148.988 / 2 = 74.494. That SHOULD be 74 due to sig figs, but we'll just make it 74.5 since it's so close, and it gives us a better estimate.
In comparison, last year's Droid RAZR MAXX HD was estimated 32 hours on its 3,300 mAh battery. 3,300 / 32 = 103.125.
The smaller Droid RAZR HD had only a 2,530 mAh battery, and only 24 hours of battery life. 2,530 / 24 = 105.417. 105.417 + 103.125 = 208.542. 208.542 / 2 = 104.271. We'll say 104.
That's not an entirely fair comparison though, since we are talking about two different screen sizes here: 4.7" on the RAZR's, and 5" on the Ultra & MAXX. So we'll divide each figure by its respective screen size to
theoretically determine how much charge it takes to power an inch of screen on these devices for an hour.
74.494 / 5 = 14.899
104.271 / 4.7 = 22.185
That means (in theory, of course), that the new phones are about 67% more power efficient than the old phones. Quite an impressive leap. That could be attributed to many things, such as the more power efficient system on a chip and potentially a more advanced AMOLED screen, plus any software
black magic tricks Motorola incorporated in these new phones. However, we have no way of telling if these figures are accurate in their real world representations just yet, but when you consider that these phones essentially have an always active screen and always on voice recognition, this is quite incredible.
The Moto X will likely have similar power efficiency to the Droids, depending on how much power the extra sensors in the Moto X end up drawing (such as the dual LTE antennas). It will likely be very close so we can calculate a rough guess of the X's battery life based on our figures.
It takes about 14.899 mAh to power an inch of screen for one hour. The Moto X is rumored to have 4.7" of screen (I think. If the actual size is less, that's better.). 14.899 * 4.7 = 70.025 mAh to power the Moto X for one hour, so if we divide the battery capacity of the Moto X by this, we SHOULD (theoretically) get the X's battery life. So 2,200 / 70.025 = *drumroll*...............31.417.
So ignoring rounding errors, the Moto X should get around 31 hours of battery life with typical use.
THEORETICALLY.
TL;DR: I predict about 30 hours.