When the Bluetooth radio is active it not only turns on the receiver (which consumes power) but also periodically transmits to see if any known devices are in range.
When paired devices are on and within range, they do communicate occasionally even if not being used, and thus consume some power.
Does Bluetooth use battery when not connected?
Many people recommend disabling Bluetooth on your phone to get better battery life. In our testing, having Bluetooth on but not actively connected to a device used a negligible amount of battery power over several hours.
Is it OK to leave Bluetooth on all the time?
If your device hasn’t been updated, the easiest way to avoid BlueBorne is to disable its Bluetooth and use it as little as possible. But leaving your Bluetooth on all the time can be dangerous, and hackers are exploiting the technology to access private information, spread malicious software and more.
Should I turn off Bluetooth when not in use?
Windows, Android, Linux, and iOS have been vulnerable to BlueBorne in the past. Millions could still be at risk. So, yeah, turn off Bluetooth if you’re not using it or if you’re near anyone you don’t trust. But you likely don’t use Bluetooth most of the time.
How much battery power does Bluetooth use?
When Bluetooth has an active paired connection to a hands-free device it consumes 2.5 mw. As the battery capacity of an iPhone 8 (not plus) is about 6900 mwh, if Bluetooth was the only thing using power the battery would run down in about 2800 hours, or about 3 months.