Bluetooth Battery Usage

I just don’t get it. Maybe someone can help me understand.
Yesterday I used my phone for 1hour45minutes playing music via Bluetooth. This barely used 1% battery. In fact it actually didn’t change %.
If I use the Optimus pro playing music over Bluetooth for this amount of time, it’ll drain approximately 25%.
my phone is 5500mah,watch is 800mah.
doesn’t add up at all.
seems BT drains considerably more on the watch than the phone.

My biggest issue is with BT draining battery so fast. For 2 reasons, 1. Because i want to be able to listen to music without worrying about battery. 2. Because it seems to be a fixable issue.


Very simple . You have to realise that if you are walking around with a expensive phone full of expensive components it will differ greatly from a watch with cheaper components . Thats why these watches are cheaper etc . Like the old saying " you get what you pay for " . Obviously the software as well can play a part as well . The good thing is these watches are getting betting all the time and the prices are still staying low so happy days eh :+1:.


Perfect. Suspected that to be the case. I guess I just needed to hear it.
Yes I agree and it’s fine. Even more than fine. Leaves room for future excitement.
No doubt with this watch my mind is truly able to realize what is possible. Not just a hope.

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After typing that last message, I went out for a walk while listening to an audiobook (why does e=mc2?) via BT from the Pro. I started to remember that the expensive phone I am using is a 200usd MI Max 3. 6.9" screen, 5500mah battery, 6gb ram. I’ve actually been able to get 18 hours of screen on time with it.(full use, not just screen on)

Also, I have been in the market for some truly wireless earbuds. The buds have about 50mah in each bud, yet can get 2 to 4 hours of playback.

So I guess what I am saying is that something seems off, at least a bit.
No doubt putting all this tech in such a small package adds to the cost and complexity as well. But the phone has to power 6.9" screen and everything working all the time.

I am not complaining… Just curious and wondering.
Not even looking for answers really as I don’t suppose there are any really.

The main thing is I can get through a full day without charging, even with listening to music up to 4 hours and gps on 2 hours and perhaps making a few calls and sending some messages.

My mind is slightly obsessed with its future perfection though :ok_hand::rofl:


I know nothing about about bluetooth hardware or radio technology in general, but that’s not going to stop me from taking a guess :slight_smile:

Maybe the smaller size of the watch antenna means it takes more power to achieve the same range.


…because the earbuds are only a receiver. The BT in the watch is a receiver and transmitter. Transmitters use much more power than receivers. Also, Newfred1 is correct in the assumption to a certain extent. Most transmitter/receivers use automatic gain control. The weaker the received signal, the higher the compensating automatic gain. Weird how the speed of light NEVER changes, but time does.

Alright! So in theory if I have the transmitter closer to the receiver, the transmitter should use less power?
I’m only on chapter 2, so he’s explaining that right now. So weird…i love it.

With my Asus zenwatch on the left wrist and bt headphones with receiver on right ear, the connection would go in and out. With the Optimus pro, I have noticed that it doesn’t skip unless I really cover it up on the left side. Badically it seems to have a much better connection than the Asus zenwatch 2. Which I had to wear on the right wrist while running and listening to music.
Anyways, it’s probably negligible.
Probably more to do with hardware software integration.

To be honest, the clamping will only be active on the receivers. The earbuds are just a receiver. The signal is clamped (attenuated) on the receiving end so as to prevent clipping distortion. The transmitter in the watch will transmit at a preset power. I have noticed that the Optimus Pro has a very robust bluetooth, so I think it’s transmitting a lot of power. Bluetooth, BTW, is very similar to WIFI, but with a shorter range and different transmission rate.
Hey I just had a thought! (ow that hurt) I think the optimus pro actually has two bluetooth on-chip transmitter/receivers. This makes sense because it has two seperate chips with on-board bluetooth. This would explain why “c8” appears in available devices under bluetooth settings. “C8” is ON THE LOW POWER CHIP!
Google search Bluetooth V4.0. It utilizes lower power for fitness information, and higher power for other applications. The technology is new, so manufacturers are probably not taking advantage of the full potential yet.

I’m quite sure that it has two Bluetooth chips as well. One is the low power (c8) and is always on ( even in light os mode) and is not capable of sending and receiving files (there’s a known issue on wiiwatch 2 as this app communicate to c8 chipset only). The other is the “regular one” and can be turned on and off from the toggle or settings page.
I wonder if there’s a way of using the c8 chipset for Bluetooth calling… Could be a great feature as it is part of the Nordic chip (non Android OS related and so not restricted by Google security policy)… As far as I know there are some headsets with c8 chip, so maybe is just a firmware configuration needed.

That the bluetooth calling functionality that we had on the 5.1 watches didn’t make it to the 7.1 watches isn’t because of Googles security policy, but rather because it has been difficult to make for these watches

But, since you say that the c8 chip is already used in some headsets, it could be that it would be easier to get bluetooth calling working on that chip instead of on the regular chip. It might also be difficult to get the c8 chip to work together with android(or maybe its easy, idk). maybe they could make bluetooth calling available, but only in low power mode

As for the changes in googles policy, they made it so that watchdroid couldn’t show notifications for incoming calls or messages any longer. Using the c8 chip wouldn’t help for watchdroid as the policy restricts the app on the phone from requesting access to the call and message information(as long as the app is published on the play store)

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