I thought I'd share my experience in case it may help others.
My phone is charged every night and I pick it up from my bedside table every morning @0600 it is in constant use for email and talktime all day as my office is in a different island and I'm always on the move between call outs, from day one the z10 had to be charged as early as 1800 compared to my torch lasting until at least 2300.
My issue has been fixed by leaving my network setting on 2G only as when I had it on 2G&3G it was constantly searching and swapping to whichever had the stronger signal. It means if I'm not within wifi range I have to switch to 3G manually for browsing etc but my phone now keeps a great charge all day long and will even out last my old torch.
Of course this is probably only going to effect you if you live somewhere that is still using 2G and the 3G signal isn't great everywhere you go, our two main telecoms providers on the island plan on having 4G islandwide by Christmas so hopefully my whole situation will be cured by then