Ok, but i just now happened to have a sudden battery drop to 04%, i tried few refreshes from a n9 qtwek refresher, and after doing 'restart bme' battery level jumped back to 15%.

As you know phone switches itself off when on low battery, even if it is just misreported to be low, but rebooting takes another unnecessary toll on power level. Anyway, there's hope i don't need to do full reboot but hopefully restarting bme(for what that stands for?) is enough, as happened just now.