# why does my s8+ suddenly turn off when the battery indicator indicates its battery is 30% full?



## OctupleGolf001 (Sep 9, 2021)

my s8+ is rooted and its bootloader is unlocked can this be the problem?, its really frustrating for my phone to just turn of when its charge is about 30% can someone please help?

when i connect the charger it shows the battery is at 0% charge


----------



## neatfeatguy (Sep 9, 2021)

Sounds like the battery is failing.

Wife's G5 or whatever LG model phone she has is 4+ years old now. About a year ago her phone would get down to around 20-30% showing left on the battery and it would just shut off. That particular model you can easily swap out the battery, so I picked up a new battery and changed it out. The phone runs like it should now and doesn't shutoff when the battery gets low.


----------



## Logan7 (Sep 9, 2021)

neatfeatguy said:


> Sounds like the battery is failing.
> 
> Wife's G5 or whatever LG model phone she has is 4+ years old now. About a year ago her phone would get down to around 20-30% showing left on the battery and it would just shut off. That particular model you can easily swap out the battery, so I picked up a new battery and changed it out. The phone runs like it should now and doesn't shutoff when the battery gets low.


Agreed, had this exact problem with an HTC 10 before.


----------



## OctupleGolf001 (Sep 10, 2021)

i have replaced the battery this year....., is it possible that the battery which was replaced is a faulty one? or is something wrong with the battery indicator?


----------



## HIGHLANDER58 (Sep 10, 2021)

OctupleGolf001 said:


> i have replaced the battery this year....., is it possible that the battery which was replaced is a faulty one? or is something wrong with the battery indicator?


It is possible the battery could be a faulty one or a fake battery sold as genuine. The battery indicator circut is usually on the battery, unless it is some cheap knock off but since batteries are fairly in expensive when compared to a new phone, try another battery you know is real and go from there.


----------



## Mussels (Sep 10, 2021)

Dead battery. Pay out the ass to get it replaced cause new phone designs are shit, or get a new phone.


----------



## FreedomEclipse (Sep 10, 2021)

Yeah. If you bought the battery from Ebay there is a 95% chance that it was a genuine fake battery - Thats how most of them are.

I wouldnt mind being sold a 'fake' battery so long as it was quick and easy to swap out for another one but phones arent built like that these days.

(And yes - the battery is toast)


----------



## eidairaman1 (Sep 10, 2021)

Memory effect on battery,it must be deep cycled.


----------



## HIGHLANDER58 (Sep 10, 2021)

Lithium ion cells have no memory effect the way that the old Nickel Cadmium and even the newer Nickel Metal Hydride cells to a lesser degree


----------



## elghinnarisa (Sep 10, 2021)

TLDR: Your phone was taught the characteristics of the original battery, if you now swapped it, it aint got no clue how to estimate its capacity unless it automatically adjusts, which most devices dont really do. This can easily lead to errors in reported remaining capacity.

Most phones uses a fuel gauge of one kind or another. Which tries to estimate remaining and used capacity in one way or another. However these estimations are not always correct and when swapping to another battery, there is nothing that says it will understand the new cell. Without updating the characteristics these gauges use to estimate current battery they will be very wrong. Since they will be working on the assumption of whatever battery cell they were designed for. Batteries do not discharge linearly, most devices have already been readied with pre-recorded characteristics of the battery cell they are going to use as to better estimate capacity.
Some devices can go through some kind of re-learning when swapping battery, some can not. I cannot remember the procedure but google around abit about your device and you might find something.

I personally use AccuBattery to keep track of my batterys health which at least does it better than I can do manually.






If you want to learn more of the subject i suggest reading up on battery characteristics, battery capacity, discharge curves and different kinds of fuel gauges, like a columb counter.


----------



## OctupleGolf001 (Sep 10, 2021)

elghinnarisa said:


> TLDR: Your phone was taught the characteristics of the original battery, if you now swapped it, it aint got no clue how to estimate its capacity unless it automatically adjusts, which most devices dont really do. This can easily lead to errors in reported remaining capacity.
> 
> Most phones uses a fuel gauge of one kind or another. Which tries to estimate remaining and used capacity in one way or another. However these estimations are not always correct and when swapping to another battery, there is nothing that says it will understand the new cell. Without updating the characteristics these gauges use to estimate current battery they will be very wrong. Since they will be working on the assumption of whatever battery cell they were designed for. Batteries do not discharge linearly, most devices have already been readied with pre-recorded characteristics of the battery cell they are going to use as to better estimate capacity.
> Some devices can go through some kind of re-learning when swapping battery, some can not. I cannot remember the procedure but google around abit about your device and you might find something.
> ...


Sometimes when my phone is 60 percent my battery drops straight down to 45 within seconds it behaves very strangely


----------



## eidairaman1 (Sep 10, 2021)

HIGHLANDER58 said:


> Lithium ion cells have no memory effect the way that the old Nickel Cadmium and even the newer Nickel Metal Hydride cells to a lesser degree


S5 did the same thing appeared to be fully charged when after a restart it only had 5% left.


----------



## Mussels (Sep 11, 2021)

Memory effect doesnt work that way on Li-Ion (Or Li-po, it's lithuin something)

Since no one can buy official batteries, they're all used, or fakes.

You can try Accubattery to estimate the real capacity of the battery over a few charge and discharge cycles


----------



## yotano211 (Sep 11, 2021)

eidairaman1 said:


> Memory effect on battery,it must be deep cycled.


I think you have the wrong chemistry type. Lithium ion cells do not suffer from memory effect.  
Lithium Polymer or LiPo are the used in cell phones, they dont have memory effects.


----------



## OctupleGolf001 (Sep 12, 2021)

my phone almost exploded today, recently when i was using my phone i heard some cracking noise in the back, when i removed my s8 case i saw that the entire back cracked, an opening was literally there in the back panel and my phone battery expanded, i can literally see the components of my phone through the opening


----------



## eidairaman1 (Sep 12, 2021)

OctupleGolf001 said:


> my phone almost exploded today, recently when i was using my phone i heard some cracking noise in the back, when i removed my s8 case i saw that the entire back cracked, an opening was literally there in the back panel and my phone battery expanded, i can literally see the components of my phone through the opening


Thermal runaway, get rid of it








						The Reason Lithium Batteries Catch Fire and Explode
					

Learn why lithium batteries catch fire and sometimes explode and how to minimize the risk of an accident.




					www.thoughtco.com
				




In Lead Acid Car Batteries, this is known as Sulfation.



HIGHLANDER58 said:


> Lithium ion cells have no memory effect the way that the old Nickel Cadmium and even the newer Nickel Metal Hydride cells to a lesser degree





elghinnarisa said:


> TLDR: Your phone was taught the characteristics of the original battery, if you now swapped it, it aint got no clue how to estimate its capacity unless it automatically adjusts, which most devices dont really do. This can easily lead to errors in reported remaining capacity.
> 
> Most phones uses a fuel gauge of one kind or another. Which tries to estimate remaining and used capacity in one way or another. However these estimations are not always correct and when swapping to another battery, there is nothing that says it will understand the new cell. Without updating the characteristics these gauges use to estimate current battery they will be very wrong. Since they will be working on the assumption of whatever battery cell they were designed for. Batteries do not discharge linearly, most devices have already been readied with pre-recorded characteristics of the battery cell they are going to use as to better estimate capacity.
> Some devices can go through some kind of re-learning when swapping battery, some can not. I cannot remember the procedure but google around abit about your device and you might find something.
> ...





Mussels said:


> Memory effect doesnt work that way on Li-Ion (Or Li-po, it's lithuin something)
> 
> Since no one can buy official batteries, they're all used, or fakes.
> 
> You can try Accubattery to estimate the real capacity of the battery over a few charge and discharge cycles





yotano211 said:


> I think you have the wrong chemistry type. Lithium ion cells do not suffer from memory effect.
> Lithium Polymer or LiPo are the used in cell phones, they dont have memory effects.











						Memory effect in a lithium-ion battery - PubMed
					

Memory effects are well known to users of nickel-cadmium and nickel-metal-hydride batteries. If these batteries are recharged repeatedly after being only partially discharged, they gradually lose usable capacity owing to a reduced working voltage. Lithium-ion batteries, in contrast, are...




					pubmed.ncbi.nlm.nih.gov
				












						Memory effect now also found in lithium-ion batteries
					

Lithium-ion batteries are high performance energy storage devices used in many commercial electronic appliances. Certainly, they can store a large amount of energy in a relatively small volume. They have also previously been widely believed to exhibit no memory effect. That's how experts call a...




					phys.org
				






			https://www.tytlabs.com/review/issue/files/453_057sasaki.pdf
		










						The memory effect of rechargeable batteries
					

Some batteries never forget




					www.science.org.au
				






			https://www.wilsonelser.com/files/repository/PL_eNews0308_LithiumIonBatteries.pdf
		










						Memory effect in a lithium-ion battery - Nature Materials
					

Nickelâ€“cadmium and nickelâ€“metal hydride batteries exhibit memory effects but lithium-ion batteries are widely believed to have none. Now, a memory effect for LiFePO4 positive electrodes that appears after only one cycle of partial charge and discharge is reported. This observation is...




					www.nature.com
				









						Slashdot
					






					m.slashdot.org
				




More info for battery mx








						BU-808: How to Prolong Lithium-based Batteries
					

BU meta description needed...




					batteryuniversity.com


----------



## Shrek (Sep 12, 2021)

As I understand it, lithium batteries don't actually lose capacity but rather increase in resistance as they age; one reason why old electric car batteries might still be good for household storage.


----------



## elghinnarisa (Sep 12, 2021)

eidairaman1 said:


> Thermal runaway, get rid of it
> 
> 
> 
> ...


did you... even read them?
phones use a different chemistry, the study specifically tested LiFePO4, which is what you find in cars, bikes etc. Well, not even there in the west actually.
They are hardly the same thing, which is why this is irrelevant.
Also the actual effect is also irrelevant for this, if you read the things you actually linked too you would see it does indeed not reduce actual capacity, just a petite voltage charge during discharge. But the actual remaining energy is unchanged. In fact, it's so far away from a "memory" effect as you can come, because it has little to nothing to do with that.
What was known as the memory effect was a battery's upper and/or lower limit to its storage capacity for energy was reduce if you repeatedly charged it to that point. Eg charge it to 80% every time, sooner or later the memory effect will kick in and 80% will be the new fully charged.

There is absolutely no effect what so ever, that is like that, with lithium ion batteries.
Again, did you even read what you just posted or did you just take headlines as confirmation?

So yes, it is true, they have no memory effect. Because calling what they found as a "memory effect" is not correct. Because it is nothing like what we have known to be the memory effect caused on other battery chemistry compositions. The only memory part here is that these small voltage variations are "remembered", but they are again, _petite _and irrelevant since capacity still remains unchanged. And again, for a battery chemistry type that isn't even relevant to the topic at hand so... yeah.

TLDR: They thought lithium-ion battery types discharged with a nice perfectly smooth voltage curve, they found out the curve is not perfectly smooth. Thats it folks.


----------

