Nonetheless, power consumption is based on applications you are using. If you are using heavy applications & games, you need a main power source. But if you are using lite applications (like Browsing internet etc), there shouldn't be a real problem with battery.
Edit - If you are traveling and need to use heavy applications. Battery will be a significant problem. You will always have to look out for plugging points. In Delhi, even Metro & DTC Buses have plugin points.