Database Users

Galaxy Tab Battery Charging Mystery

I am sure most of you have realized the fact that when you unplug the Tab from the charger, even it showed fully charged, the battery drop right down to 99% or 98%, which is not that normal with other android phone.
I took a deeper look here. I have a widget which can monitor the battery voltage. When the Tab is connected to the plug and fully charged, the voltage is showing at around 4150mv, which is the normal fully charged voltage for most of the android phones. The moment you unplugged the charger, the voltage drop to around 4070mv. I guess most of the phone judge the battery level by voltage. The differences of the voltage makes the battery level drop to 99% or 98%.
Another fact I found is that the voltage changes quite a lot when the Tab is on different loads. A simple example is that when I wake my Tab up from a sleep mode (black screen to desktop), I can see that the battery voltage widget showing a 100mv drop. (This can be easily reproduced, just put a battery widget which can show voltage on desktop, lock your screen for a few minutes, after that unlock your Tab and keep looking at your voltage for a few seconds, you will notice the difference).
I basic Physics tell me that this kind of voltage drop is cause by the running current and the internal impedance of the battery. But still I am not so sure about the 100mv drop is normal or not? It is bigger that is should be (causing by the not well made battery which have larger than normal internal impedance)?
Sorry for the English style, it is not my mother tongue. Thank you. More discussion is welcome.

I also notice the last 10 or so percent going in minutes

nothing either of you are describing is abnormal behavior for Lithium ion cells.
almost all of this has been discussed ad nauseum.

crazy talk said:
nothing either of you are describing is abnormal behavior for Lithium ion cells.
almost all of this has been discussed ad nauseum.
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Click to collapse
Well, there you go

Theres another mystery to be resolved. How come a two amp/hour charger needs four hours to charge a four amp battery instead of the aprox two hours it should take?
Sent from my GT-P1000 using XDA App

Tiamath99 said:
Theres another mystery to be resolved. How come a two amp/hour charger needs four hours to charge a four amp battery instead of the aprox two hours it should take?
Sent from my GT-P1000 using XDA App
Click to expand...
Click to collapse
The charging current is not constant. The maximum is 2 amp. But this is probably available when the batter level is very low. As the batter level goes up, the charge current goes down. Meanwhile, the charger would provide power for the device to operate if you were charging it with power on, which uses some of the amps.

The explanation does not satisfy me. It would certainly explain why it charges in a little bit more Time than expected with the 2 amp charger, the problem is that the charging time is about four hours, that's double the time needed for charging.
For example the Archos 70 internet tablet has a 3000 miliamp battery and a 2 amp charger. Time to full recharge? 90 minutes.
As it should be.
Sent from my GT-P1000 using XDA App

Charging current is usually lowered for example when battery overheats while charging. Also, if you use the device while charging, then of course you are slowing down the charging as well.

Tiamath99 said:
The explanation does not satisfy me. It would certainly explain why it charges in a little bit more Time than expected with the 2 amp charger, the problem is that the charging time is about four hours, that's double the time needed for charging.
For example the Archos 70 internet tablet has a 3000 miliamp battery and a 2 amp charger. Time to full recharge? 90 minutes.
As it should be.
Sent from my GT-P1000 using XDA App
Click to expand...
Click to collapse
Hmm, the Archos is not telling the whole truth. It'll try to explain what I know. Lithium based batteries have a two stage (some people say three!!) charging process.
The first phase is the constant current phase, this pumps in as much current as possible (within the constraints of the charger, battery size, battery temperature etc). So with a 2 amp charger the full 2 amps will hit the battery, probably less if the device is switched on as the device will take some of the power from the charger.
The first phase continues until the battery voltage is about 4.1 or 4.2 volts then phase 2 starts. At this point the battery is probably about 70-80% charged. The 2nd phase is a constant voltage charge and will take the charge from 70-80% up to 100%.
The 2nd phase is what takes the time, as the voltage hitting the battery is now fixed at 4.1/4.2 volts the charging current steadily reduces as the battery becomes more charged. Therefore it may take 20 minutes to get from 80% to 90% charged but 40 minutes to get from 90% to 100%.
There is a small graph on the bottom of this web page-
http://shdesigns.org/lionchg.html
So why do some devices take longer to charge then others? Apart from different chargers & size of the battery the other main factor is the charging circuit in the device. Some devices do not do the slower phase 2 charge resulting in a battery that is only 70-80% charged, the device will of course tell you it is 100% charged but it is not, so for example out of the 3000mA/H battery in the Archos only ~2500mA/H will actually be availble. Other devices may push the charge voltage on the phase 2 charge to make it quicker - this is seroiusly bad for the battery though.
Make sense??

faugusztin said:
Charging current is usually lowered for example when battery overheats while charging. Also, if you use the device while charging, then of course you are slowing down the charging as well.
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Right but when you charge it with all apps closed and the screen off the power consumition is minimal so it shouldn't affect the charging time very much.
Sent from my GT-P1000 using XDA App

m2te said:
Hmm, the Archos is not telling the whole truth. It'll try to explain what I know. Lithium based batteries have a two stage (some people say three!!) charging process.
The first phase is the constant current phase, this pumps in as much current as possible (within the constraints of the charger, battery size, battery temperature etc). So with a 2 amp charger the full 2 amps will hit the battery, probably less if the device is switched on as the device will take some of the power from the charger.
The first phase continues until the battery voltage is about 4.1 or 4.2 volts then phase 2 starts. At this point the battery is probably about 70-80% charged. The 2nd phase is a constant voltage charge and will take the charge from 70-80% up to 100%.
The 2nd phase is what takes the time, as the voltage hitting the battery is now fixed at 4.1/4.2 volts the charging current steadily reduces as the battery becomes more charged. Therefore it may take 20 minutes to get from 80% to 90% charged but 40 minutes to get from 90% to 100%.
There is a small graph on the bottom of this web page-
http://shdesigns.org/lionchg.html
So why do some devices take longer to charge then others? Apart from different chargers & size of the battery the other main factor is the charging circuit in the device. Some devices do not do the slower phase 2 charge resulting in a battery that is only 70-80% charged, the device will of course tell you it is 100% charged but it is not, so for example out of the 3000mA/H battery in the Archos only ~2500mA/H will actually be availble. Other devices may push the charge voltage on the phase 2 charge to make it quicker - this is seroiusly bad for the battery though.
Make sense??
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Click to collapse
Wonderful explanation mate.
But still I just can't understand why it took one hour and 50 minutes to go from 10% to 60% . In theory it should be phase 1 charging at full 2 amps hour.
Since the 50% charged is about 2 amps , shouldn't it have charged that amount in an hour?
Sent from my GT-P1000 using XDA App

I've been wondering this too. I read in other reviews that it takes 3 hours for a full charge but It took me 3.5 hrs to go from 55% to 100%. sounds like samsung is very conservative with it's stages.

The first problem is something that those of us with Droid Incredible devices have had for a long time. Many people resort to bump charging (i.e., charging to 100%, unplugging for a little while, then plugging it in to let it finish charging). It's an annoying problem.

Need help here my xda fellows.
I am not sure if this is normal, but my tab drops from 70% to 58% overnight with flight mode on and no apps opened. (i use lanucher pro if that counts)
Another weird thing is when i turn off the tab and charge, that battery meter only shows about half full and no matter how long i charge it for it stays the same. But then when i fire it up, android system tells me its 98%. And when i try to turn it off and charge it, now the meter shows almost full and will eventually shows that 100% symbol.
It seems to me some ppl get excellent battery life but not in my case. Could there be any problem with the battery? (running jk1 fw non root).
Sent from my GT-P1000 using XDA App

Another issue is that once the charger hits 100%, it shuts off. While the tab is plugged in and on, it will drain the battery down some...maybe to 95%...before the charger turns back on. However the whole time it is plugged in it will show 100% after having reached max charge.this is by design on almost all new battery devices to prevent damage to the battery and simultaneously prevent people from complaining their battery is draining even though it is plugged in.
This also explains why some people see such a quick drop after unplugging. If they happen to unplug at the bottom of a trickle charge cycle.
Again, not a bug.
Sent from my SCH-I800 using XDA App

As I have noticed these issues with my Tab as well, these were all very well explained and knowledgable replies.
Just to put in my two cents, I have noticed that the Tab actually seems to charge noticably faster if I leave it on, rather than turning it off. I do, however, usually turn off everything on the power widget and put it into airplane mode as well, mind you. But, the speed in which it recharges while turned on as opposed to the recharge speeds when completely shut off are fairly noticeable.
Anyone else notice this with their Tab or any other device, and/or have some insight regarding why this occurs? Kudos for the previous informative explanations, btw.

Power usage output

I recently got a few solor chargers that charges a 1500ma battery, and return it charges the 1500ma i have in my phone. It takes about 8-12 hours depending on sunlight to charge the solar battery. If my math is correct, the solar is charging the battery at a rate 80mah? I want to beable to have my phone hooked up to this charge majority of the time when i am driving, or taking a greyhound bus. How much power in MAH it uses? Right now with teamwhisky i can go a full day (about 16 hours)on a battery, and wifi is always on and internet is being used for email, ect.

You assumption is not correct. The charging is not on a linear scale. It's more complicated subject than I have time to write. But there are 2 scales that are working at the same time But, basically the charging would go more or less like this say 1st hour 25% (375mah) charges...2nd hour 25% (281mah) of the remaining amount then 25% of the remaining amount (210mah) like this plus the resistance of accepting the charge goes up as it gets more charged. To answer the second part this all depends on the sun, your use rate etc, but simply put if you are driving in the sun with one of these hooked up you will not lose either net or voice connection....and after all isn't that what you want. Read up on how the battery is used on the phone you will find that the phone sees 100% @ 4.2 V and 0 % @ 3.7volts or something like that.. Like I said there is a lot more to this than just a linear equation.

Thanks, I am wondering what solar panel will be best to use to maintain a charge on the battery wile powering up a phone. I am open for suggestions or options. I can get a solar that produces 6v with 50mah. I been told that its not the volts that i cant increase it's the milliamps. So can i get something to increase the amperage with out increasing the volts to maintain a steady charge to the battery while it is being used?

On a linear scale you are using about 18-20 mah per hr So, the effective thing is to have a charger that has say 3000mah as it will charge a 1500 battery faster simply put. This is hard to explain easily but a 4.2-4.5 volt 3500 solar charger would work very well and charge more than you can use. There is one I saw its like 70 bucks, kinda big but if it works... it may be worth it.

Phone charge discussion

Hi, I have searched and read the related threads in the forum about SGS2 charging issue. It is true that the phone charges really slowly compared to other phones. I just tried playing a game and charging at the same time and the result is the phone was barely charging, which I think is a ridiculous. It means the power consumption when playing a game is almost equal to power being charged.
How about everyone else's charging time? I read before it seems Samsung capped the charging rate at 700mA. Not sure if it's true.

hbkmog said:
Hi, I have searched and read the related threads in the forum about SGS2 charging issue. It is true that the phone charges really slowly compared to other phones. I just tried playing a game and charging at the same time and the result is the phone was barely charging, which I think is a ridiculous. It means the power consumption when playing a game is almost equal to power being charged.
Click to expand...
Click to collapse
Being a high powered phone, it consumes a lot of battery power when being used and very little when in standby. So if you want to charge it at full rate, don't use the phone at the same time.
hbkmog said:
How about everyone else's charging time? I read before it seems Samsung capped the charging rate at 700mA. Not sure if it's true.
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Click to collapse
Without using the phone, my average charging time has been 3 hours and 43 minutes to get from totally flat 0% to 100%. Normal daily charge from about 20% to 100% takes 3 hours.
The charging rate is capped so that the battery and phone does not over heat during charging. An overheating battery will expand and possibly explode, thus potentially causing phone damage and user injury. That is why the charging rate is limited.

Same as posted before zero to full about 3 hours .
jje

Same here...more than 3 hours for 0-100%...even this reduced charging heats up the phone..

KE series of firmware charged really slowly, but it was fixed after KE7 I think. With the latest KG3, charging from 0 to 100 is done in 2.5 hours with wall charger.
Also don't forget that this phone has a 1650 mah battery. Don't expect it to fill it up at the same time as a 1300 mah one found in most other phones.

i usually charge at 20%. i also get about 3 hours to full charge

I still think someone should increase the charge current and see how it fares. It's all about tweaking and testing.

Charge the phone turned off, that's the fastest way to charge it.

Well personally I think it's kind of counter productive if the phone can't charge properly when you use it at the same time.

RogerPodacter said:
I still think someone should increase the charge current and see how it fares. It's all about tweaking and testing.
Click to expand...
Click to collapse
So why don't you do it yourself and tell us how it goes?

Bump
Would be nice to see in Cog or Vill

So how much truth is in statement that you can't use navigation, listen to MP3s and charge via car charger because your phone will be discharging anyway?

New note 4 and question about first charge

Hello friends,
So I just got my Note 4 and i'm wondering how long should I keep it in charge for the first time? And should I drain it on first use or charge it when it's at let's say 20%??
Thanks in advance.

14 hrs, dont drain, battery should be between 20-80% before charging in normal use, fast charge off.

@zurkx
Thanks for the reply.
Are you sure about the 14 hours??? I thought Li-ion batteries don't need that long of a charging time !!!

XeroHertZ said:
@zurkxAre you sure about the 14 hours??? I thought Li-ion batteries don't need that long of a charging time !!!
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Click to collapse
Please happily ignore that "advices".
Use Fast charge, charging takes exactly till the battery is full, that's about 1,5 hours for a full charge.
I don't see ANY sense in charging a LiIo battery "fuller than full", just impossible nonsense.
LiIo batteries suffer of aging, slightly increased by the number of charges, highly (!) increased by overheating, not of any memory effects.
There is NO "breaking in" of the Note 4s battery, amperage of fast charge doesn't come even near the safety limits, won't cause quick degradation or overheating.
So just don't listen go the immortal myths and "ancient wisdom" propagated by people not aware of the fact that battery technology indeed changed over the decades.

Chefproll said:
Please happily ignore that "advices".
Use Fast charge, charging takes exactly till the battery is full, that's about 1,5 hours for a full charge.
I don't see ANY sense in charging a LiIo battery "fuller than full", just impossible nonsense.
LiIo batteries suffer of aging, slightly increased by the number of charges, highly (!) increased by overheating, not of any memory effects.
There is NO "breaking in" of the Note 4s battery, amperage of fast charge doesn't come even near the safety limits, won't cause quick degradation or overheating.
So just don't listen go the immortal myths and "ancient wisdom" propagated by people not aware of the fact that battery technology indeed changed over the decades.
Click to expand...
Click to collapse
Thanks Chefprol.I have done some research on charging the battery and have come to a conclusion that once it's charged I can use it straight away but and then drain it to 18 to 20% then charge it fully.

Chefproll said:
Please happily ignore that "advices".
Use Fast charge, charging takes exactly till the battery is full, that's about 1,5 hours for a full charge.
I don't see ANY sense in charging a LiIo battery "fuller than full", just impossible nonsense.
LiIo batteries suffer of aging, slightly increased by the number of charges, highly (!) increased by overheating, not of any memory effects.
There is NO "breaking in" of the Note 4s battery, amperage of fast charge doesn't come even near the safety limits, won't cause quick degradation or overheating.
So just don't listen go the immortal myths and "ancient wisdom" propagated by people not aware of the fact that battery technology indeed changed over the decades.
Click to expand...
Click to collapse
Thanks ! i tought it would be a old myth to first drain the batery and then fully load it but as far as i know its only with old phones and mp3 players and such.
hope i will get my note 4 today ! waiting for it since monday

Fast Charge is not really a useful feature for me, it just hurts the battery more in the long run

what about the thoughts on conditioning the battery?
Sent from my SM-N910C using XDA Free mobile app

There's no need to condition the battery, its a lithium battery.
If you're having battery drain issues I would suggest you clear your data cache.
ddaharu said:
what about the thoughts on conditioning the battery?
Sent from my SM-N910C using XDA Free mobile app
Click to expand...
Click to collapse

this is the same guy making up stuff about the note 4 GPS being bad.
dont listen to fools.
First charge needs to be 14 hours to trickle charge the battery to full and make sure the meter is calibrated to a full battery.
fast charge does reduce battery life since it charges at higher voltage and amperage. any battery gets damaged a little by that. best is a slow charge (preferably Qi) at a normal charging voltage. Slower the better for longer battery life. if you want convenience over battery life then by all means fast charge and mess it up and replace after 2-3 years.

Who's post are you referring to?
zurkx said:
this is the same guy making up stuff about the note 4 GPS being bad.
dont listen to fools.
First charge needs to be 14 hours to trickle charge the battery to full and make sure the meter is calibrated to a full battery.
fast charge does reduce battery life since it charges at higher voltage and amperage. any battery gets damaged a little by that. best is a slow charge (preferably Qi) at a normal charging voltage. Slower the better for longer battery life. if you want convenience over battery life then by all means fast charge and mess it up and replace after 2-3 years.
Click to expand...
Click to collapse

arjun90 said:
Who's post are you referring to?
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Click to collapse
It's mine. That guy already bumped into me a while ago, now it's time for his revenge.
I'll care for that, now...
---------- Post added at 02:09 PM ---------- Previous post was at 01:32 PM ----------
zurkx said:
this is the same guy making up stuff about the note 4 GPS being bad.
Click to expand...
Click to collapse
So here we go; you asked for it...
My critism about the Note 4 refers to it's GPS receiver, which is "deaf" compared to the competition and shows frequent signal drops.
More here: http://forum.xda-developers.com/note-4/general/gps-close-to-unusable-t2948602
dont listen to fools.
Click to expand...
Click to collapse
Indeed - have a look:
First charge needs to be 14 hours to trickle charge the battery to full and make sure the meter is calibrated to a full battery.
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Click to collapse
I already advised to realize this is 2014 battery technology, not the ancient batteries of the past.
Short: There is no "trickle charge" with Lithium-Ion-batteries.
See this: http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries - quote: "The difference lies in a higher voltage per cell, tighter voltage tolerance and the absence of trickle or float charge at full charge."
fast charge does reduce battery life since it charges at higher voltage and amperage. any battery gets damaged a little by that.
Click to expand...
Click to collapse
Quote: "The charge rate of a typical consumer Li-ion battery is between 0.5 and 1C in Stage 1, and the charge time is about three hours. Manufacturers recommend charging the 18650 cell at 0.8C or less."
"C" is the capacity, 3220 mAh with our Note 4's battery. So we're save to charge with a current (milliamperes, "mA") of up to 3220 mA - if we follow the manufacturer's advice for the older type of batteries of that kind (18650 is an old warrior in the field), there's still 2576 A left.
So what does our fast charge supply deliver ? Look at it's ratings: 5 V, 2 A (2000 mA).
So even fast charge is far below the limits - our real limit is 3220 mA, but fast charging just uses 2000 mA.
Sound and safe.
Wonder about me highlighting "higher voltage" in zurkx's highly elaborate statement in red ? - Answer is above: The voltage does NOT change, it is NOT higher. Of course not !
The worst enemies of LiIon batteries are heat and age.
Heat is generated by a) placing the device at a hot spot (like behind the car's windscreen or in bright sunlight), b) by using demanding features like 4K video recording or highend games, c) by charging .
a) Your call. Just don't let your Note get hot. Overheating destroys your battery in no time. We're lucky we've got an exchangeable battery - so nothing to really worry about.
b) Your call. See a).
c) Charging produces some heat, especially on the "last mile", when the battery is "almost full", because the battery is a bit reluctant of getting charged up to the brim. So more heat is generated in that last phase. It's not much, won't reach the safety limits. It just can't, because the build-in charging circuits limits the current if heat gets up.
By the way: That integrated charging circuits are propped with safety measures, checking charge, condition, temperature and the like.
So even if you hook up a charger capable of providing 20 whopping amperes, the circuits just won't let that happen.
There is no way of providing the battery too much current; it's automatically limited.
best is a slow charge (preferably Qi) at a normal charging voltage. Slower the better for longer battery life.
Click to expand...
Click to collapse
Again; welcome to the 21st century. We don't need any slow charge. It's the opposite.
Charging right slow has the danger that apps on the phone draw more power than the charge provides. That may drain your battery instead of filling it.
Plus: If you hook up the charger for long, it will be recharged (charge gets "topped off") frequenly. And every new charging attempt has a slightly negative impact on the battery's life; it's like wearing it a bit down. - Charge often, reduce your battery's life. That damage is tiny, by the way. But it is there, so hooking up your charger for many hours slowly kills your battery.
Now for the aging:
if you want convenience over battery life then by all means fast charge and mess it up and replace after 2-3 years.
Click to expand...
Click to collapse
LiIon battery ARE AGING, up from the time of manufacture.
You all know that: You charge a device like you're told by the instructions - but after 1 to 3 years you notice a severe drop of usage time, a drop of capacity.
That's aging.
NOTHING you can do against that but buying a new battery.
So your battery will lose it's capacity over time; if you use it or not. You all know that, you all experienced that.
With the Note 4, we can happily buy a new battery if the old one runs out; it's that simple. But as a normal Li Ion battery reaches it's shelf live after 2 or 3 years anyway, there's NO (!) need of burdening it and you with slow charge. The results are exactly the same, with the difference that you save precious time with fast charging.
And now allow me quoting again:
dont listen to fools.
Click to expand...
Click to collapse
Have a nice day, all of you except one.

youre completely wrong.
The QuickCharge tech charges at higher VOLTAGE and AMPERAGE.
http://www.androidauthority.com/quick-charge-explained-563838/
Quick Charge 2.0
Voltages 5v 5v / 9v / 12v
Max Current 2A 3A
Snapdragon 200, 400, 410, 615, 800, 801, 805
The rest is just BS as usual. You have no idea what youre talking about. Dumping 9V (Samsung Note 4 AFC) into a 5V battery makes it charge hotter and faster and degrades it significantly. After two weeks of fast charge i lost a small chunk off the top of my brand new battery.
just bad advice as usual.

zurkx said:
youre completely wrong.
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Click to collapse
Yes, indeed. I was completely wrong by believing you'd understand some simple things.
In fact, I am not sure if I should take your statements for serious or just for a joke.
The QuickCharge tech charges at higher VOLTAGE and AMPERAGE.
Voltages 5v 5v / 9v / 12v
Max Current 2A 3A
Click to expand...
Click to collapse
So you REALLY believe that changes of the output voltage of the POWER SUPPLY lead to the BATTERY charged with more volts ?
You can't be serious. That's technically impossible.
Let's put it easy:
If you insert your power supply into a 110 V receptacle in the USA, you get 5 V output.
So according to your "logic", using the same power supply in Europe (230 V) increases the voltage to 10 V ?
No. Just NO.
That higher POWER SUPPLY voltage is used for fulfilling the rule W = V * A (Watt = Volt * Ampere); just to be able to squeeze more power through the power supply's cable.
In the Note 4 and in the charging circuit, that voltage OF COURSE will be regulated down to the regular charging voltage - just with the benefit to carry more amperes.
So the CHARGING VOLTAGE stays the same; it does NOT follow the voltage supplied by the POWER SUPPLY. It never does.
So fast charging does NOT (read that: NOT !) increase the charging voltage. It cannot.
Got that now ? - Or do I need to put it ever more simple ?
It does not help using swearing words like "fool" or "bull****".
But it could help just saying: "Oh, sorry, I was wrong. - My apologies."
Make yourself at home with the basics of lithium ion and charging technology. THEN speak up.
Ah, overlooked something:
After two weeks of fast charge i lost a small chunk off the top of my brand new battery.
Click to expand...
Click to collapse
1) Hope that chunk fell somewhere you were able to pick it up again.
2) How to you KNOW that ? I expect a detailled description about how you did the magic of finding out that your battery doesn't charge to 100 %.
3) If you KNEW that fast charging would kill your battery, wise man - why did you allegedly use the feature ? - Sorry, man... Your statements are not very trustworthy. I guess you never used that feature, just say so to strengthen your shaky point of view. Please don't mess with a perception psychologist.
4) If your battery really suffered, that might be due to your highly acclaimed and absolutely pointless 14-hours-charging-marathons, causing a permanent charge on/charge off cycle, weakening your battery.
So please just stop bashing a real useful feature of the Note 4. If you just love waiting ages for batteries to charge - your preference. But please stop spreading false facts about things you very obviously are not at home with.
And a last thing which might stop that aimless harassing fire of yours: I am HAM, a licenced amateur radio operator, holding the highest German licence class. These are the people who know a bit about volts and amperes.

how hard is it for you to understand that quickcharge 2.0 outputs higher VOLTAGE and AMPERAGE to charge the battery ? The charger charges the BATTERY AT 9V 1.67A up to 50% and then switches over to the regular 5V 2A charge rate. INPUT VOLTAGE (110V or 230V) has nothing to do with OUTPUT VOLTAGE. It charges the battery at 9V REGARDLESS of INPUT VOLTAGE.
edit:
also it has nothing to do with the cable. you must be crazy if you think a cable issue exists whether you transfer 15W or 10W across it. the cable is rated for well beyond that. the reason for the higher voltage is that modern lithium ions can accept high voltage charge rates with limited damage at low amperage. the reason they cut it off at 50% is the battery would be severely damaged if you tried to charge it to 100% and overshot. so yes quickcharge 2.0 really does charge your battery at a higher voltage than it was designed to be charged at. and no they dont have a magical transformer on your phone to go from 9V to 5V. otherwise they would be using it all the time and fast charge 9V to 100%. the wall plug is the only thing which has a transformer and the phone uses what it gets from there. they arent going to build half of another wall plug (9V DC-DC) and stuff it into the phone. it would generate heat and add bulk. Instead the PMIC "spikes" the battery with higher voltage and keeps it roughly constant (load modulation) by communicating with the quickcharge 2.0 AFC on the other end.

Hopeless.

I just love these battery threads, there's always some muppet who says the battery needs conditioning and must first be charged for a suitably ridiculous length of time. When it's charged it's charged, lithium batteries have no memory effect so the idea of conditioning them is moronic
Sent from my SM-N910F using XDA Free mobile app

yes they have no memory effect. why ? because you say so.
other people believe otherwise because they actually test things out for themselves :
http://www.psi.ch/media/memory-effect-now-also-found-in-lithium-ion-batteries
http://pocketnow.com/2013/05/03/li-ion-batteries-memory-effect
http://www.nature.com/nmat/journal/v12/n6/full/nmat3623.html

no need to keep it for 14 hours, as they said in the catalog you only need to charge it till it's full, then unplug the charger.

Hello again !
After all cooled down a bit, here's some more information about that dreaded HIGH VOLTAGE fast charging uses which seemingly makes some of you wet your pants.
First, there's an experiment you can do yourself. You don't need to do - but it's quite impressive and gives you some proof of the things I say.
Get two 9 V batteries; the small rectangle ones we all know. Connect the positive contact of the first battery with the negative contact of the second. Thus you get an 18 volts DC power source.
Get a thin, isolated wire, short-circuit the open contacts with the wire. Wait.
Nothing special will happen, maybe the wire will get a little warm - and your batteries will eventually die.
(If you use a VERY thing wires, it might heat up.)
Now take a length of the same wire, do the same using your car's battery (12 – 13.8 V DC).
WARNING !
1) Take the battery out of the car, set it on solid ground with nothing combustible near !!! Do NOT try this with the battery still in the car !!!
2) Use pliers to connect the wire with the battery contacts !!!
3) Do that OUTDOORS !!!
Short-circuit the battery contacts using the pliers with the wire.
You don't need to wait. The cable will turn into a smoking, burning, white-hot thing in an instant.
Huh ? - We've got 18 V with just nothing happening, we've got just 12 V wreaking instant havoc and destruction !?
Amperage is the key !
Voltage alone does not cause the destruction, it's the amperage.
9 V batteries cannot provide sufficient amperes for killing the wire; 12 V car batteries do.
Short: High amperage kills wires, high voltage doesn't.
So back to our topic...
To fast charge our Note 4's battery, we need power, watts. But the tiny wires in the Note 4 can't withstand a high wattage; they would heat up like the wire connected to the 12 V car battery.
So Samsung uses a little trick, according to Ohm's law: W = V * A, W is watts, V is volts, A is amperes.
So we can achieve a high wattage by EITHER using a higher voltage OR a higher amperage.
Higher amperage does not work because it will kill the tiny wires in the Note.
So Samsung raised the voltage for carrying more watts from the power supply via the internal Note 4's cabling to the charging circuit.
That higher voltage gets transformed down to the normal charging voltage at the charging circuit.
Your battery is charged with the usual voltage, but with the benefits of a higher amperage.
That's all the magic: That higher voltage is used to carry more wattage to the charging circuit, but not beyond. Nothing else.
And that's why it does not harm your battery; charging voltage will not change - your battery just gets charged faster, always monitored by the charging circuit which will lower the charge accordingly if needed, so your battery will always be safe. That's why the "last mile" (charge from about 92 % to 100 %) takes more time to charge - because the charging circuit automatically lowers the charge to protect your battery.
So don't be afraid of that higher voltage; it never reaches your battery, it is just a means for transferring higher wattage via tiny wires.
Note: You ever wondered why Europeans use 230 V instead of 110 V ? - That's the reason. Being able to carry more watts over regular power lines without risking the wires heating up too much. It's not a means of destruction, it's the opposite.

Not a conspiracy: Fast vs 'Slow' Charging

Ever since I first got my Note 4, I've loved two things about it more than almost everything else: battery life and charging speed.
Two nights ago, I was bored and - I know, it's a strange thing to do when bored - decided to see how fast fast charging was compared to normal charging. It took my phone about 123 minutes to fully charge from 0 to 100% with fast charging disabled.
But that's not what I care about. What I care about is the fact that, before I disabled fast charging and fully charged my phone from 0, I would typically have about 10% left after a twelve hour cycle that included around 5 hours of screen-on time.
After my slower charge, I found that, after about 11 hours, I'd had my screen on for 4.5 hours, and my battery was still sitting at 55%. This improvement absolutely astounded me, and I want to encourage all of you to see how your mileage varies (or perhaps doesn't) by disabling fast charging.
I'd like to add that I've always been a huge proponent of fast charging, and I've always dismissed the common notion that it's bad for a phone's battery. But I can't ignore my own results.
EDIT: I should add that this was without power-saving mode or airplane mode enabled at any point in time. And the screen brightness was set to the same value I use generally, and not the minimum I'd use in total darkness.

I haven't used fast charge except for the first few days I had the phone. I just never needed my phone charged fast.
I can get about 6.5 hours of screen on time with around 20% battery left on power saving mode.

droidx2.3.3 said:
I haven't used fast charge except for the first few days I had the phone. I just never needed my phone charged fast.
I can get about 6.5 hours of screen on time with around 20% battery left on power saving mode.
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Click to collapse
I'd had fast charge enabled until two days ago because I never saw anything but advantages to it. I also should add that I don't use power saving features until I'm down to at least down to 15%. Glad to hear you're getting good performance

I only use fast charging. If I do a heavy use day, I get about 5-5.5 hours of SOT and run out. Not sure how long it lasts.
On average, I charge my phone every third day and get 4-4.5 SOT.
I think my battery life is pretty exceptional. I don't leave the phone on the charger overnight, it gets unplugged immediately and I usually put it on the charger around 15 percent.
Yes, I"m not a heavy user usually. Depends on my work load, sometimes it only lasts two days.

I remember hearing this back in the day. Users reported that trickle charging (ie. Usb to computer) would yield better battery life.
I was curious if this would be the case when I first heard about the fast charging when the note 4 was released, but I haven't tested it yet.
http://forum.xda-developers.com/xperia-z/help/trickle-charging-improve-battery-life-t2332947
I use a spare oem battery/cradle charger. Which does not have fast charging, so the battery would technically be charged slower than through the phone with fast charging. I haven't noticed any difference in battery life between the two.
Then again, my phone usage changes by the time I swap batteries.
Sent from my Note 4.

I guess I'm different than most. It's nothing for me to kill a battery in a work day. When I'm 50% +/- I'll plug in because I never know when I'll need a full charge or where I will be an need it. When going out of town I typically will carry at least one of my two backup battery packs.
I will keep power saving mode on and my screen at full brightness. No WiFi enabled but I do use BT from time to time.
5.5 to 6 hours usage sounds about right for me. 24-48 hours on one charge and I say someone isn't using their phone enough.... LoL

Im running Pac Rom 5.1.1 on Note 4 DE and the charger definitely makes a difference.
A "normal" charger (pretty much anything under 2.1A) will charge much slower than a 2.1A charger.

mithusingh32 said:
Im running Pac Rom 5.1.1 on Note 4 DE and the charger definitely makes a difference.
A "normal" charger (pretty much anything under 2.1A) will charge much slower than a 2.1A charger.
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But have you noticed any difference in your battery life after a fast charge vs a slow charge?

Bicknasty said:
But have you noticed any difference in your battery life after a fast charge vs a slow charge?
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Click to collapse
You guy need to repeat this charging business in a scientific test manner.
For example.
1) Discharge to 50%-80% (choose a level.)
2) Slow charge to 100%.
3) Run a loop of a video at some preset brightness, not auto, until the battery is at 50%-80% again. Note the time.
4) Fast charge to 100%.
5) Repeat 3 in the exact same way.
Then compare the times of video playback for the two charging techniques.
My guess is that if you were to do it right, you would get identical results.

nabbed said:
You guy need to repeat this charging business in a scientific test manner.
For example.
1) Discharge to 50%-80% (choose a level.)
2) Slow charge to 100%.
3) Run a loop of a video at some preset brightness, not auto, until the battery is at 50%-80% again. Note the time.
4) Fast charge to 100%.
5) Repeat 3 in the exact same way.
Then compare the times of video playback for the two charging techniques.
My guess is that if you were to do it right, you would get identical results.
Click to expand...
Click to collapse
You'd also have to play a movie that is stored on phone and go on airplane mode, since signal strengths change power usage of radio.

Slow and steady wins the endurance race
Owners of electric rc cars/planes often charge lipo batteries to tailor their output for various track conditions. Faster higher voltage charges are more punchy and have increased output but suffer shorter run times. Slower lower voltage = milder output and longer run times.

Jugger naut said:
Owners of electric rc cars/planes often charge lipo batteries to tailor their output for various track conditions. Faster higher voltage charges are more punchy and have increased output but suffer shorter run times. Slower lower voltage = milder output and longer run times.
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Click to collapse
Slower or faster discharge in an electrical motor depends on how much and how fast the motor can consume energy and how quickly a battery can dispense it - this relates directly to the performance of the motor like horsepower and torque. The charge used up is still the same. The amount of electricity stored depends only on the chemical composition of the battery, not on how you charge it. So faster or slower discharge still uses up the same amount of electricity - the energy stored/dispensed remains the same.
On the other hand, in a very demanding situation like RC, a faster charge can afford a faster peak discharge rate of battery. This is due to how the chemicals in LiPo batteries undergo transformations between homogeneous and heterogeneous states depending on the rate of charge. The faster the charge, the faster the maximum rate of discharge. A common misconception is that a slower rate of charge will amount to more charge stored. That is generally incorrect. Slower charging can only benefit the useful lifetime of the battery.
A display or a cpu of a smartphone are unlike an electrical motor in that they consume the same nominal amount of energy for a given task and at a very low rate. The rate of energy consumption for a smartphone is far lower than the possible rate of discharge of the battery is has.
For example, you can charge (and discharge) a battery in smartphone like S6 in about 80 minutes (and that is still FAR slower than you can possibly charge/discharge such a battery.) But the battery will last many many hours even under the heaviest load. So slower charging is pointless for smartphones.