oh and one other thing. Believe it or not LI-ion batteries have a finite lifespan. Anything from a couple of weeks to a year or so (depending on the number of charge cycles and how the battery is treated). The capacity of a battery is reduced slightly EVERY charge. Quite simply, buy a new battery. You will be amazed at how shagged your old one was.

ProTip: Go to dr_frost_dk's battery thread and follow the link for the SCUD blue battery. It only costs like $5 and has ~15% greater capacity than the original.

If after all this you still have suck battery life, you have broken something. Either diagnose with powertop & top or just re-flash and start again.