I've used Battery Mix, which I loved because of the great graphs and useful info. But it prevents the installation of APK's, so I had to uninstall. I'm now using Team Battery Bar (Pro in my case, free also available). It is only a Notification Bar feature (no detailed battery usage available), I've found it to be accurate and configurable and useful. Mainly, I don't need to have my glasses on to be able to see the battery level at a glance (g).
Also, thanks to James for that interesting info on codes.