For those still rocking a dev unlocked Windows Phone (and who are paranoid about your battery), you may want to check out the cool little homebrew app 'Battery Meter'.

It's just a simple app (with a nice tile) that shows you how much battery life is left in percentage form. You launch it and there you are--no more mystery.

You can grab the app here and thanks to gkoonjul at XDA, for throwing it together.