Been using grand for about 6 days..
I get battery backup of about 20hrs with 5+hrs of screen on time.. I guess this is okay..
App for battery performace is battery stats plus
Nokia 1100 > Nokia 6600 > Nokia N72 > Nokia n95 > Nokia N86 > Htc Touch > Xperia U > Galaxy S2Plus > Galaxy S2 > Galaxy Grand Duos > NEXUS 5
to pm me in case u need technical support (not developer level
) or want any suggestion.