Does Bluetooth drain smartphone battery?

No one likes the dreaded screen telling you to connect your smartphone to a charger, or the “friendly” reminder that you only have 20% battery left.

And it seems as everyone has their own ideas of who’s the real culprit and the best tricks to conserve battery. From closing certain apps to turning off notifications. You may have heard that turning off Bluetooth can save that precious battery as well.

So just how much battery does Bluetooth consume?

The roots

The notion that Bluetooth consumes a lot of battery seem to stem from the time when Bluetooth first was introduced in the mid to late 90s. And it’s difficult to say just how much power it consumed back then relative to the average mobile phone battery. What we do know however is that just as our devices have improved in the last 20 years, the battery capacity has also improved significantly.

The chart below sheds a little light on the battery capacity development for a few mobile phones from 2007 to 2018.

Comparing the iPhone X to a “smartphone” ten years ago (Sony Ericsson K550i), the battery capacity has just about tripled over the last decade.

And the Bluetooth technology itself has evolved to adapt to the new consumer tech landscape. Wireless speakers, headphones, cars and even toothbrushes – we now have an ever increasing supply of devices to connect to with our smartphones.

Yes, this product actually exists.

When Bluetooth was invented, it was intended as a substitute for a data cable. Meaning connecting two devices (point-to-point) to transfer data.  In the years since, innumerable Bluetooth compatible devices and use cases have sprung forward, and Bluetooth has adapted to this changing landscape.

Bluetooth Low Energy (BLE) was introduced in 2011 as Bluetooth 4.0. The key difference is in the name – the low power consumption. While it’s not the best way to stream music to a speaker, or use for phone calls, the BLE protocol is optimized for applications that only need to exchange small amounts of data periodically, for example location services. Nearly all smartphones and other connected devices today natively support BLE.

Different use case, different Bluetooth

Bluetooth Classic is not an obsolete version of BLE as both protocols have their pros and cons. Both versions co-exist and are used for different products. For example when streaming music from your smartphone to a Bluetooth speaker or wireless headphones, the phone will use Bluetooth Classic. When using IPS the smartphone is using Bluetooth Low Energy – which has a small but negligible impact on the battery.

To illustrate some of the main differences between Bluetooth and BLE, we’ve put together this infographic.

So, for the final question…

Should you turn off Bluetooth to save battery?

As we’ve outlined above, power consumption is highly dependent on the specific use of Bluetooth. For example, streaming music to headphones does consume more power than using Bluetooth LE for a connected smart watch, or when using location services like IPS. It’s also worth mentioning that there are other factors than just Bluetooth that can consume larger amounts of power. For instance, a large brightly lit screen (as many smartphones have) can be a major power hog.

On one hand, turning off Bluetooth can save you small or negligible amounts of power. On the other hand, you can rest assured that having it turned on won’t drain the battery – and will make future connections to devices all that much easier.

We’ve put together a little flow chart to help you make the decision.