If your phone or tablet, or whatever you’re using, has a lock screen, just be sure to keep it locked while your tunes are playing. It’s going to use the same amount of battery as if you were attached to a Bluetooth headset. In general, if you play music on a device through its own speaker, it’s going to take up a little less battery than if you’re using Bluetooth; that’s not exclusive to Bluetooth speakers. Your device has a Bluetooth receiver, and it takes power to operate. If the Bluetooth setting on your device is on, it’ll use a little more battery, period.\r