Could you install the BetterBatteryStats (the link will explain everything and you be able to download an apk) to check whether something isn’t using up your battery? For example check that there isn’t a kernel wakelock, or a partial wakelock permanently using your CPU, and check the many other things that could drain the battery (this app gives a lot of raw data).
This is the problem I had on my FP2, and it turns out it was a faulty core module. You can check the thread where I describe it: Process irq/288-wcd9xxx draining battery