Battery app for Windows Phone 8 is now free - lockscreen juice info, live tiles and usage charts
It has it all - battery status on the lock screen, not one or two, but three types of live tiles, as well as graphs and charts with your battery usage, including in landscape view.
The Battery app also shows you the time since last charge, and now with the latest update you can get all of that info for free, and forget about your range anxiety. Get it from the link below.
source: Battery (WP Store)
Things that are NOT allowed: