Motorola Droid RAZR MAXX

ok, so i got a maxx a bit over a week ago, and did the 3 battery cycles that people posted about online to get the best battery life. i have never gotten more than 36 hours or so before it powers down because of low battery. this weekend, i used it a lot because i was off from work, but after 27 hours of heavy usage it was at 5%, and i'm just wondering if i got a defective one because i've read reviews of people using it for 2 FULL days (over 48 hours, not just 36 hours) and having 30% or 40% battery life left. i'm only asking because i only have another day or two left before i can return or exchange it, and am only allowed one return, and was going to call them today and maybe have them send me a new one. any help or advice would be greatly appreciated...