Pixel continually receives charge from hotspot

dairymilkbatman

I routinely work remote with my phone plugged into the macbook.
Bloody macbook keeps charging the phone, even when at full charge and rinses the macbook.
I tried buying a usb block WITHOUT charging capability and it still does it - at a lesser rate. (3A I am guessing).

Any way to prevent this?

zzz

dairymilkbatman

You can try:
OS settings -> security and privacy -> exploit protection -> USB-C port -> off

But that would also turn off data transfer.
Assuming that you're plugging the phone into the laptop for data transfer?
Not sure how you could get data without charging.

Eagle_Owl

dairymilkbatman
Since release 2024123000 GrapheneOS supports limiting charging the battery to 80% with support for bypass charging.

This works for me by using one of the two USB ports of my MacBook Air M2, maybe your MacBook is an older one which possibly doesn't support it.

This also requires the setting in the GOS menu under Settings/Battery/Optimized Charging:
Limit for Charging (80%): switch it to [on]

And maybe important: I use my older Pixel 7 Pro as WiFi hotspot, USB for charging only.
In other words: no USB tethering, only WiFi/WLAN for data transmission (over the air, not USB cable).

For security reasons (see link below) I never connect my MacBook via USB for data transmission, only charging.
Setting in GrapheneOS menu: Privacy & Security/Exploit protection/USB-C port: Charging only

Reference:
The Hated One (YT Video): Why phones are more secure than desktops

dairymilkbatman

Yeah I use it to for internet connection and most of the time I am in environments without WiFi :p

Thanks for the hint though!

DeletedUser237

dairymilkbatman Did you try to see if MacBook have an option to disable charging devices via usb when not plugged?

dairymilkbatman

Yes I did have a poke around but failed to find anything. I am reasonably sure that there is no option.
Unless there is some CLI command I can pass.

dairymilkbatman

I solved this problem by isolating the + wire in an old USB cable so that there is only data flow. Best I could do :p

dairymilkbatman

Thanks for the reply Eagle.

Are you positive on your assertion? because I have an M2, and my pixel 7 is limited to 80% however, the mac battery significantly discharges in this scenario - which, I admit, doesn't make sense. This is further validated because the pixel battery never goes below 80%

I would much prefer to have the old fashion cable connection because I want to limit WiFi radiation in my environment, for both health reasons and purity of the lab (sensitive equipment around). A side; bluetooth radiation would be preferred over WiFi however, it doesn't look like we have the bluetooth hotspot functionality :/

Eagle_Owl

dairymilkbatman
Yes, I am sure, because I am using the battery monitoring app BatteryBot Pro, which protocols the real charging activity.
A few seconds after the battery is charged to 80%, the battery icon at the status bar shows the shield and BatteryBot Pro change its status from “Charging” to “Not charging”.
And the protocol of BatteryBot Pro then has no additional data to write, because the charging process has paused. Really. ;-)

But this function seems to be not perfect, because sometimes the charging begins again after some time and is working like without the limiting function.

Maybe my MacBook's behaviour isn't similar to your's, because I am using Lockdown mode?
This blocks any data transfer that has nothing to do with battery charging.

BTW: my name is “Eagle Owl”. Look at the profile picture – it's a kind of Owl (Bubo bubo), not an Eagle ;-)

Skyway

dairymilkbatman I tried Bluetooth hotspot between my two pixels and it works.

GrapheneOS

dairymilkbatman It uses bypass charging, meaning it uses the charging source to run the phone instead of using power from the battery to preserve the battery.

gk7ncklxlts99w1

Besides draining the battery on the laptop, is there any other reason not to keep your phone plugged in and charging after it's 100%? Modern batteries no longer have that old problem where it would reduce its lifespan if you kept charging at 100%.

Eagle_Owl

gk7ncklxlts99w1 Modern batteries no longer have that old problem where it would reduce its lifespan if you kept charging at 100%.

Unfortunately that is mostly theory.
Most manufacturers love planned obsolescence because it maximizes their profits.
They don't care what it does to our planet, because by the time the “end of the world” comes, they will be long dead.

Modern technology must not only be invented, but then actually built into products!

And in some products it needs the right software to bring it into the hardware:
Example: Pixel phones!
Before the release of GrapheneOS 2024123000 there was no bypassing of the battery after charging to 100%. The hardware was ready for it, but not the software.

Example: Sony VAIO laptops in the 90's!
These had a battery-saving charging technology and you could choose the range in which the battery should be kept if you often use the device locally on the power adapter (e.g. always keep it between 40 and 60 %).

Example: Apple MacBooks today!
These will never real end charging if you keep them connected on the charger.
Because the battery packs inside are not easy to change and some people buy a new MacBook if they get in trouble with a bad battery experience…

gk7ncklxlts99w1

Eagle_Owl

You say it's mostly theory, but to my understanding, modern batteries have built in limiters - when you charge to 100%, you're only really charging to about 80% of what the battery is capable of. This isn't just a theory, from my understanding.

I'm not sure if that's what you're referring to when you're citing those other examples. I'm not sure what you mean by "bypassing of the battery after charging to 100%".

de0u

Eagle_Owl Example: Apple MacBooks today!
These will never real end charging if you keep them connected on the charger.

https://support.apple.com/en-us/102338

Eagle_Owl

de0u
Thank you for the link, but this method is not enough, if you are using a MacBook as a Desktop computer.
And I don't notice that the charge pauses at 80%.
If I don't make sure to unplug the charger in time, the MacBook Air M2 is always charged to 100%.
This is not the battery-friendly way that Sony offered real battery saving 20 years ago!

de0u

Eagle_Owl This method is not enough, if you are using a MacBook as a Desktop computer.

I am unaware of a report issued by a knowledgeable party supporting the claim that this approach is inadequate with respect to some standard. Presumably such a report would include a battery expert reporting on observed charge/discharge behavior over some period of time.

Eagle_Owl And I don't notice that the charge pauses at 80%.
If I don't make sure to unplug the charger in time, the MacBook Air M2 is always charged to 100%.

I have an M2 MacBook Pro. The behavior of the charging system is not easily predictable. Unplugging the device from the charger even briefly once a day can cause it to "decide" it should charge to 100% often. But if I leave the device plugged in for more than a week it will generally discharge to 80%. Right now my MPB's battery status is "On hold: 80%" and it has been that way for days.

Eagle_Owl This is not the battery-friendly way that Sony offered real battery saving 20 years ago!

These are not the batteries of 20 years ago. A 2004 iBook G4 had a 60 watt-hour lithium-ion battery (source). A 2023 MBP M2 Max shipped with a 70 watt-hour lithium-polymer battery (source). The chemistry is different, the construction is different, and the charge controller includes 20 more years of understanding.

I am not a battery expert, so I am not claiming that what Apple is doing is perfect or even good. But it is easy to observe that the claim that modern Apple devices "will never end real charging if you keep them connected on the charger" is not accurate.