One of the new Siri-related features Apple introduced in iOS 8 is the “Hey Siri” hotword that gives a device always-on listening abilities when it’s plugged in and charging. The feature doesn’t work when an iPhone or iPad is disconnected from the power supply, likely a measure meant to conserve battery life, but iDownloadBlog reports there’s a way to enjoy “Hey Siri” all the time, without having to charge the device at the same time.
Read more here:: Boy Genius Report