[Q] Battery draining fast then slow? topic

I have an issue with my hox, I am running ARHD with the kernel included. The problem is about the battery % stat,it's not updating correctly,for example battery is 80%,I use the phone for 5 mins then suddenly its 72%,at 2% it lasted 1 hour on full brightness. Also it does not always update after sleep (for example I go to sleep,battery is 50%,when I wake up is still 50%,after I use it 1-2 mins is 45%). I've tried to do a full discharge,charged the phone to full while it was off,booted it then charged it some more,deleted the batterystat.bin . Problem still occurs and it happend on other roms (for example MIUI V5). Any ideas?