Have you tried to flip it to roam only and see if signal is better? If it is, it won't eat the battery so much. Or, put in airplane mode and turn wifi on.
I'm in a house right now with terrible service. The roam only helps so thank you.
I do find that with airplane mode and WiFi I lose 12% overnight. But with decent service I only lose 6-7% with 3 g on overnight.
Not sure why it sucks so much on airplane. Anyone else get that?
Sent from my Nexus S 4G using xda app-developers app