There's a list of things one can do to improve battery life. The easiest (attention, black humor) is turning the device off, next to switching it to airplane mode. In general these two things are not worth a consideration -- but with all things operable, I've seen no smartphone yet lasting more than 2 days. My old HTC Buzz currently makes it a week (7 days, and still 40%+ left) -- but it neither has a SIM card inserted, nor Wifi enabled (so you see, most energy goes for being permanent online; I just carry the Buzz as backup, since I didn't yet transfer all apps to my new phone). My Motorola Droid 2 ends up at about 70% at the end of the day (after about 17h runtime; so it would basically last ~2 days), and I'm not really doing that much.
But to provide something useful, here comes a short (and incomplete) list:
- One of the largest energy consumer is the display -- so this area is where you can save most:
- make the display timeout as small as possible (and just as large as needed). 30s is a good value.
- you probably do not need 100% brightness, so turn it down as low as possible. Handicap: if it is not bright enough when you need it, it's hard to find the appropriate setting. On some devices/ROMs some toggle-switches are integrated into the status area (if not, there are apps to do this), so you can blindly draw it down and hit the correct corner to toggle it up.
- at least on the Motorola Droid, there's one consumer clearly topping the display using twice as much: UMTS up/download. So if you do not really need to constantly transfer big data, or rely on UMTS as there's no GSM available (unlikely), switch 3G off and force your phone to GSM mode. Not relevant for data only, but also for talk (just with less energy difference).
- WiFi is also a main consumer -- even in standby. So when not needed, switch it off (same for Bluetooth).
- as we are in this category: Though often suggested, GPS standby is not worth mentioning -- as long as it stays standby. Only problem here are apps that will then make use of it for localized ads and the like. So if you rarely use GPS, just turn it off as well.
I could almost write a book on this, as there would be so much more to be mentioned. So just some little additional hints concerning apps which might be of assistance:
- Battery Saver has an interesting concept: Running a service in the background, it regularly checks the systems report on the strength of cell and Wifi signal (the system updates those data either, so that's no costly action). Finding one (or both) of them too weak to be useful (e.g. if you're sitting in a bunker, or some Faraday box), it switches them completely off -- and checks in intervals whether it makes sense to turn them back on. This is especially useful if you often experience "dead zones", where your cell radio would then power up to max, desperately trying to find some cell tower. And talking about "limiting your smartphone experience" makes no sense here: you either get no contact, as thee's no signal ;)
- JuiceDefender is available in multiple versions (ranging from basic to plus to ultimate), and some hold it very high. It tries to save energy in several ways -- the best known being to "stutter" your data, by switching off all background sync, only permitting it in intervals. It offers much more possibilities, also depending on the version used.
Again, these are only very basic hints -- there's much more one could do. So you could use some Profile apps like e.g. Tasker or EasyProfiles, Timeriffic or Llama -- to adjust your settings based on different situations. So you can e.g. put your Android device to airplane mode when you sleep (time based), adjust screen timeout when reading ("when runs"), switch Wifi off/on when leaving/returning home (location based), and many other things. Guess you've got the idea :)
If you're still awake at this point, and like to read more, checkout What can I do to increase battery life on my Android device?