For those of you with the dreaded media scanner sucking away all your battery, here's something worth trying.
Seems to be an issue with some non-brand name sd cards not working properly. Try a different SD card. Update to latest firmware if you don't already have done so. Lastly, try downloading SD Card Monitor from the Play Store to verify the sd card is working properly. If the app reports multiple attempts to read from the sd card, thats likely the problem.