Three observations from this screenshot (assuming we can trust the native battery monitor in Android 4.0.4) .
The Galaxy Nexus battery can last for 48 hours with light use.
- Even when always-on, the Wi-Fi radio took only 3% of battery energy.
- By comparison, the cellular radio took 3x the energy of the Wi-Fi radio.
A little fine print: I don't make or receive many calls, so the cellular side wasn't exercised much during this time, maybe a couple of 10-minute calls. Most of the processor and screen usage was due to my 'Aruba Utilities' application, which is quite compute-intensive, and exercises the Wi-Fi radio quite substantially. I set Wi-Fi to 'always-on'. The Galaxy Nexus Wi-Fi interface is dual-band but during this period I had it set to 2.4GHz only. GPS was off. Cellular interface had 3G and data enabled but I don't have many background apps running, and when I'm at work or at home the phone's on Wi-Fi.
