Would assume that when you are debugging mobile applications on your phone which presumes you install new packages and software to that phone. Is it possible that these newly installed applications cause additional battery drain? You can use simple charge meters like https://play.google.com/store/apps/details?id=com.devdroid.batteryguardian to find any such battery consumers.
Log.d messages do get executed even on built / distributed releases, yet the output is not really shown as filtered on production devices. The battery consumption for that would be miniscule.