It seems that Nokia Lumia 800 Windows Phones are having some battery issues. And it seems that it is software related than hardware related. According to Nokia, they are going to fix them ASAP.
Not sure what are the actual problems and also it seems the problems do not affect everyone. According to Nokia Support Discussions, if there are no push notifications, no background running, the battery looks fine.
However, if they start to turn on those notifications, the battery will drop significantly. I copied one of the response from Nokia on the issues: -
“ We understand that some people have expressed concerns about battery life on the Nokia Lumia 800. Early investigations show that the majority of people are enjoying the full Nokia Lumia experience without any problems. A software update in early December will include improvements to power efficiency, while a second update in early January introduces further enhancements to battery life and battery charging. Both are planned updates and will be made available via Zune. We recommend that anyone who still has concerns contact local Nokia care representatives at their earliest convenience.”
BTW, I have to mention here that the above excerpt are from the forum and may or may not represent Nokia. Nevertheless, if it is a genuine problem, I am sure it will be fixed. I don’t think Nokia can afford to have such an issue coming up now.