What are the components that indicate the battery charge level of a mobile phone?

Thread Starter

jonlim

Joined Mar 18, 2019
17
Hi! I have a mobile phone that has a blank screen but working (it rings when called). When I am attaching this phone into a pc via usb and using a tool, the tool is saying that its battery is at -1%. Maybe this is the reason why screen is blank. Also, when attached to a pc via usb, it is only recognized as an unknown device.

Can someone please tell me what are the components that indicate the battery charge level of a mobile phone? These components maybe the reason for the problem.

Thanks in advance.
 

Alec_t

Joined Sep 17, 2013
10,429
There is probably a dedicated 'Coulomb-counter' IC inside the phone which monitors and controls the state of charge and discharge of the battery.
Can you be sure that the mystery 'tool' isn't itself part of the problem?
 

Thread Starter

jonlim

Joined Mar 18, 2019
17
Can you be sure that the mystery 'tool' isn't itself part of the problem?
Thanks! Hopefully not! but it is the tool that flashes firmware and also, upon researching on this problem, i saw one thread that discusses same problem and the poster was saying he is seeing that -1% battery quickly shown every after around 10 on-off of the phone.
Can you further guide on how to identify this component? Like probable location on the pcb, markings, brand, code, etc.
Thanks.
 

narkeleptk

Joined Mar 11, 2019
375
Post model of phone and photo's of the circuits.
It sounds like either a internal short or firmware in phone is shot. Did this happen all of sudden, after a drop, after trying to root it, bought it like this?
 

Tonyr1084

Joined Sep 24, 2015
3,636
On your former thread I posted that it sounds more like a processor problem. I'm no phone expert, so coulomb counter is something I've not heard before this morning.

My reasoning is that if the battery is saying it's at negative 1 percent - that's a situation that can not possibly be. Not unless the battery is "Positronic". Meaning it has a surplus of (positive) protons. (or an absence of electrons - neither of which makes sense to me)

It's possible your phone has been hit with a virus. I've heard of that happening before - the virus thing. I know nothing about how virus' affect phones other than "it happens". You may have to do a factory reset. Maybe - just maybe - that might clear the issue. But the electronics on cell phones is so small you need specialized equipment to work on them. A microscope being just one of them. Special soldering irons or hot air pencils to desolder and remove defective components. But even there is a problem - identifying the defective component(s). Honestly, unless you have these tools or access to them - good luck.
 

Alec_t

Joined Sep 17, 2013
10,429
Perhaps your battery has aged to a point where it can no longer retain a charge and its protective IC is turning it off for safety when the screen (quite a current-hungry thing) tries to fire up. A new battery might cure the problem (then again, it might not :( ).
 

ci139

Joined Jul 11, 2016
774
it is quite likely that due
-- there is (usually) a unique combination for phone×battery
then the software can use
-- a specific math.-stat. model derived experimentally to !estimate!
(-1-) the aging of the battery
(-2-) the aging related expected voltages at different levels of charge/discharge @ T(°C) × recent-Power-usage
(-3-) the "actual" capacity of the battery @ T(°C)
 

Thread Starter

jonlim

Joined Mar 18, 2019
17
On your former thread I posted that it sounds more like a processor problem. I'm no phone expert, so coulomb counter is something I've not heard before this morning.

My reasoning is that if the battery is saying it's at negative 1 percent - that's a situation that can not possibly be. Not unless the battery is "Positronic". Meaning it has a surplus of (positive) protons. (or an absence of electrons - neither of which makes sense to me)

It's possible your phone has been hit with a virus. I've heard of that happening before - the virus thing. I know nothing about how virus' affect phones other than "it happens". You may have to do a factory reset. Maybe - just maybe - that might clear the issue. But the electronics on cell phones is so small you need specialized equipment to work on them. A microscope being just one of them. Special soldering irons or hot air pencils to desolder and remove defective components. But even there is a problem - identifying the defective component(s). Honestly, unless you have these tools or access to them - good luck.
I was able to successfully flash firmware which should solve any software issue but the problem persists.

In repairing this, i would really be using an expert's hands. I can find a lot of technicians around that can do the work for me but my worry is the trouble shooting part as i wish not to hear that i need to replace the board and/or lcd...

Thanks
 
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