Database Users

This is why your battery drops 10-15% in the first 20 minutes.

Plain and simple: When the Evo is fully charged, it begins running off its battery until you plug it back in. It DOES NOT trickle charge whatsoever after it reaches 100%. When you're using your Evo on the charger, and it's showing full 100% charge, it is running off the battery, not the AC plug. And then when you unplug it, well, we all know what happens next. The battery meter drops insanely fast to the actual charge of the battery, which could be very low, depending on how long it's been sitting idle at 100% on your charger.
So all those times you've charged your Evo overnight, only to take it to work the next day and be at 80% within an hour? Your Evo was running off its battery for what I'm guessing was most of the night. It takes my Evo about an hour to two hours to fully charge back to 100%. Let's say you put your Evo on the charger at 11PM, it'll reach full charge by 1AM at the latest, and then run off its battery until whenever you take it off the charger in the morning.
Workarounds?
1) Turn your Evo off while it's charging.
2) If you must leave it on for an alarm clock, put it in airplane mode and end all CPU intensive tasks to minimize battery drain.
3) When you wake up, unplug it for 10-20 minutes (still experimenting with this number), and then plug it back in to top it off. Once it reaches 100%, take it off the charger, and go about your day.
Try it out for yourself. When your Evo is 100% charged, take it off the charger immediately, and I highly doubt you will lose the 10%-15% within minutes. Please share your findings.

Er... Point of note, mine does it even if I pull it off the charger right when it turns green.

Post some technical schematic or other type of proof that shows that this circuitry isn't available in the EVO. That will prove beyond a doubt if what your saying is true.
That being said, only a group of the most retarded electrical engineers would design a charging system as you've described. It is INSANELY easy to build Li-Polymer charging circuitry that does the following (and it pretty much has to do these):
1. Detects battery temperature, and disables charging as a protective measure. In an emergency case it should shut off the device it's powering to allow the battery to cool down. This is a design requirement, or else your house burns down as you dump water on a Lithium fire thinking it's going to put it out. If you have a HERO, you can easily test this. Running the wireless tethering, GPS/Navigation, and Music with the screen running heats up the phone a ton. You'll notice the status light blink green once, then red a couple of times. This means that it's plugged in but not charging. Cool the phone down and it turns solid red again (charging).
2. Disable charging cycle when battery reaches a certain voltage. VERY SIMPLE voltage detection circuitry! The designer can of course adjust a gap to have charging turn back on when it dips below a certain voltage. Usually since this circuitry can be made with a decent amount of precision, that "turn back on" voltage ends up being roughly when the battery discharges to maybe 99.5%. That's just a guess, I admit but there's no harm in having the circuit switch on and off, even if it's often.
There are also a few other circuits that prevent the cell from blowing up in your pocket, like a current sensor to prevent an overcurrent. There's also some stuff that prevents you from being able to discharge the cell below it's avalanche voltage. In case you don't know what that is, when a Li-Ion battery discharges to a certain voltage, it avalanches to 0 (quickly falls). If it hits that point, you've pretty much ruined the battery and it will never charge the same again.
Anyway, this is stuff they taught and had design labs on back in college. While I have no actual proof that the phone wasn't designed as the OP describes, I find it highly unlikely. If this is the behavior that the circuitry exhibits, I would find it easier to believe that it's a design flaw, probably because some idiot didn't compile the correct bill of materials.

I haven't got any schematics or any sort of technical information on the subject. All I know is, it works wonders for me. When I take my Evo off the charger in the morning, it literally drops to ~90% within minutes. Once it does that, if I place it back on the charger for ~20 minutes, it charges back to 100% and stays there for 45 minutes to an hour.
I'd urge anybody who is noticing the immediate 10% to 15% drop in battery to give this a shot.

I would turn it off while I'm charging it overnight, but I use it as my alarm clock

Me Too
I am seeing the exact same behavior as the OP. This is really lame. Because of this, most people will end up losing 10% of their battery every day. Pretty lame.

I charge my phone overnight every night. Never noticed a problem and I just checked my battery and its at 88% and has been off the charger for 2.5hours so I'm not seeing the rapid discharge issue some people are seeing.

I don't think so man, I leave my screen on full brightness while it's charging, and if what you said was true it would go dead on the charger.
I think it's more likely the cells haven’t charged equally, so you get a big initial drop.

Grims said:
I don't think so man, I leave my screen on full brightness while it's charging, and if what you said was true it would go dead on the charger.
I think it's more likely the cells haven’t charged equally, so you get a big initial drop.
Click to expand...
Click to collapse
I'm beginning to think that once the battery reaches 100% full, it runs off the battery until it reaches some arbitrary percentage. At which point it starts charging until it reaches 100% again, and then continues this cycle.
I'm testing a few other things right now. Part of me is convinced it reports 100% charge when it's actually below that level.

Krynj said:
I haven't got any schematics or any sort of technical information on the subject. All I know is, it works wonders for me. When I take my Evo off the charger in the morning, it literally drops to ~90% within minutes. Once it does that, if I place it back on the charger for ~20 minutes, it charges back to 100% and stays there for 45 minutes to an hour.
I'd urge anybody who is noticing the immediate 10% to 15% drop in battery to give this a shot.
Click to expand...
Click to collapse
I'll try this out to see if I can get the same kind of behavior. I guess I honestly haven't looked to see if the phone drops 10-15% after pulling it off.
Krynj said:
I'm beginning to think that once the battery reaches 100% full, it runs off the battery until it reaches some arbitrary percentage. At which point it starts charging until it reaches 100% again, and then continues this cycle.
I'm testing a few other things right now. Part of me is convinced it reports 100% charge when it's actually below that level.
Click to expand...
Click to collapse
This is what should be happening I believe, but I'd be surprised if it was set to such a huge swing like 10-15%
Grims said:
I don't think so man, I leave my screen on full brightness while it's charging, and if what you said was true it would go dead on the charger.
I think it's more likely the cells haven’t charged equally, so you get a big initial drop.
Click to expand...
Click to collapse
This is an interesting theory. I do know that when you have multiple Li-Ion cells in a battery pack, if they discharge unevenly, you have to go off of the lowest charged cell. Again, if a cell were to drop below the avalanche voltage, you'd ruin the pack all together. On the other hand, the circuitry should let ALL cells charge to 100% so it's even again. Maybe they screwed this up, that design isn't so easy! Perhaps it detects one cell as 100% and shuts off the charge. Therefore, one could surmise that if you started with an unevenly charged battery pack, you'd have an immediate decrease in charge to the rating of the lowest charged cell. The good news (maybe) is that this is sometimes implemented with software. That means that HTC could release a bug fix for this, or if we have a savvy dev, they could try to fix it. We just need to prove the theory though.
This is all just a guess, keep that in mind. If I notice something like this with my phone today, maybe I can tear apart the battery and measure the voltage on each cell (if it even has multiple cells). I have a spare, so maybe I'd be up for this. Krynj (or anyone), if you have the HTC Hero, try charging your battery pack with it, see if it exhibits the same behavior on the Hero itself. If it doesn't, then try putting it back into the EVO and see if after a night of charging, it still drops 10-15% after disconnecting it from the AC.

The reason why the battery dies so fast has something to do with the memory card. Charge your phone and take the SD card out and watch it stay at 100% for a long as time. Then do it again with the SD card in and watch it dip down fast.

Apple laptops don't charge unless battery is below 90%. If you plug in the AC and the battery is above 90%, it will just run off AC power but I don't think the battery drains any then.

My battery life has been less than stellar, but I didn't notice it dropping 10-15% instantly off the charger. I did notice that it'd drop about 10% after driving to work with xiialive streaming, which was unusual to me. The battery would start running out after about 9 hours at work. I'd be in the yellow by the time I got home, and the battery would be complaining for a charge in the evening. So that's roughly 12 hours I would be getting out of the phone after normal use.
Since I'm suspecting an issue with the charging circuitry, I just recently tried charging my battery with the Hero. After it was fully charged, I put it back into my EVO last night and haven't charged it since. It's been running 13 hours, and is still nearly full green. The charge is at about 70%. I've been trying to graph the discharge all day too. It only dropped to 87% over night, dropped to 80% when I drove to work (xiialive), and then down to 74% after I spent some time setting up icons and modifying my home screen. This is...hands down a butt ton better than the past week.
I'm not using 4G.
WiFi is off.
3G is on.
GPS is on.
Not running a live wallpaper.
Sync is running at default settings.
Widgets that could be updating constantly:
I have the Clock/Weather HTC widget running.
I have the Dictionary.com "word of the day" widget.
I have the Friendstream Widget running.
Craigslist Craignotifica app is running, set to notify me with search results.
The results are inconclusive though. Yesterday, I wiped and re-flashed DamageControl 3.2.x from scratch (backed up all apps with Ti-Backup, this means Android Market won't be notifying me if there are app updates -grumble-). So, somewhere between re-flashing and also charging my battery with the Hero caused this turn around.

apollooff320 said:
The reason why the battery dies so fast has something to do with the memory card. Charge your phone and take the SD card out and watch it stay at 100% for a long as time. Then do it again with the SD card in and watch it dip down fast.
Click to expand...
Click to collapse
Interesting.....Will have to give a try. Will report back later.

I'm waiting for some definitive results with the "use another charging device or battery" method. It seems that the EVO just sucks at recharging the battery since people who have used another phone or a separate charger seem to report better results.
I leave my phone off at night and charge it - when I turn it on in the morning it still drops 5-10% in the first 20 minutes. But during the day it drops REALLY slow, so I still can get about 13-16 hours before 15% easily.
I have manual account sync, 3g only, wifi at home, usually gps is off, auto backlight settings for screen, and I don't run too many apps in the background, I just use them when I need them.

Has anybody found a solution to this? It's really starting to bother me. I've noticed that I don't seem to have the issue if I charge -> recovery -> wipe battery stats -> reboot. That kind of leads me to believe that something is inaccurate about the battery stats and the phone instead uses the actual raw value provided by the battery instead of whatever it is that it does with the battery stats.

I can tell you this, I bought two of the cheap battery chargers off of ebay and I have two OEM evo batteries. I don't even plug my phone in anymore. I get an hour of standby at 100% from those chargers and it falls instantly when charging from the phone. I just run them down then swap them out. I couldn't be happier and they are only like 10 bucks each with 2 batteries each.
Sent from my PC36100 using XDA App

jnewkirk10 said:
I can tell you this, I bought two of the cheap battery chargers off of ebay and I have two OEM evo batteries. I don't even plug my phone in anymore. I get an hour of standby at 100% from those chargers and it falls instantly when charging from the phone. I just run them down then swap them out. I couldn't be happier and they are only like 10 bucks each with 2 batteries each.
Sent from my PC36100 using XDA App
Click to expand...
Click to collapse
can you post a link or ebay or where ever u bought it from?

Try this I'm doing it from the phone
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250641711190&ssPageName=STRK:MEWNX:IT#ht_1991wt_913
Sent from my PC36100 using XDA App

apollooff320 said:
The reason why the battery dies so fast has something to do with the memory card. Charge your phone and take the SD card out and watch it stay at 100% for a long as time. Then do it again with the SD card in and watch it dip down fast.
Click to expand...
Click to collapse
If you have apps on your sd card that are running then yes that could be the case. SD cards need power to work but I dont know how much they draw..

Time to Recharge to Full Battery

Is it just me or everyone else that is experiencing a super long time in charging their phone to full battery? I am running the froyostone latest build and I have already followed all the guides in this forum to save battery life. The issue I am having is that it takes many hours to recharge the battery to full when connected to a wall charger.
It took 5 hours to go from 30% battery to 90%.
*no i wasn't charging the phone with the phone turn off*

Zythyr said:
Is it just me or everyone else that is experiencing a super long time in charging their phone to full battery? I am running the froyostone latest build and I have already followed all the guides in this forum to save battery life. The issue I am having is that it takes many hours to recharge the battery to full when connected to a wall charger.
It took 5 hours to go from 30% battery to 90%.
*no i wasn't charging the phone with the phone turn off*
Click to expand...
Click to collapse
I have a stock battery, which I can charge from 25% or less to 100% in about 30 minutes to an hour. I think there is something wrong with your charger.

its actually not taking that long, it probably got to 90% VERY quickly, you just checked on it later... they're false numbers... what you need to do is this; run your battery all the way down.. then charge it for about 1-2hrs, until it gets somewhere in the 90's then, while plugged in, shut the phone down, remove the battery, put the battery back in, boot up the phone (the phone should remain plugged in) then load up WM, load up android with the hard buttons backlight on, then once it boots you should show higher than what you had before (if not 100%) from this point android will remember your charge and you will be able to go to 100% all the time now. (until you load a new rom)

10507 said:
I have a stock battery, which I can charge from 25% or less to 100% in about 30 minutes to an hour. I think there is something wrong with your charger.
Click to expand...
Click to collapse
I got stock battery also. No idea why it taking so long.
javolin13 said:
its actually not taking that long, it probably got to 90% VERY quickly, you just checked on it later... they're false numbers... what you need to do is this; run your battery all the way down.. then charge it for about 1-2hrs, until it gets somewhere in the 90's then, while plugged in, shut the phone down, remove the battery, put the battery back in, boot up the phone (the phone should remain plugged in) then load up WM, load up android with the hard buttons backlight on, then once it boots you should show higher than what you had before (if not 100%) from this point android will remember your charge and you will be able to go to 100% all the time now. (until you load a new rom)
Click to expand...
Click to collapse
I have already tried this but still no luck.

10507 said:
I have a stock battery, which I can charge from 25% or less to 100% in about 30 minutes to an hour. I think there is something wrong with your charger.
Click to expand...
Click to collapse
What kernel are you using?

Sichroteph said:
What kernel are you using?
Click to expand...
Click to collapse
I am using hastarin r8 kernel, but I was experiencing the same issue with previous versions and the default kernel.

I just tested the charging rate by connecting my HD2 to a stock charger from HTC which I borrowed from a friend. Charging was a lot faster.
Since I bought my HD2 used, the charger that came with it, is not the stock charger from HTC.
But I still don't understand what is causing the charging to be very slow.

How to calculate charging time
Charging time = capacity of battery x 1,4 / charging current
HD2 stock battery= 1230mAh x 1,4 / 1000mA = 1,7 hours
Best
leehobin

Two things on charging batteries:
1) First, make sure none of the pins in the battery compartment is bent. This dramatically slowed charging for me once.
2) Android keeps battery stats in a file that gets loaded with your build. THese stats are often wrong. Be sure to fully charge under WinMo, then with power still attached, boot into Android. This will adjust some of the stats and charging in Android should be fine then. There's a thread somewhere on more details here if you want to tweak your stats. The battery slows down its charging when it gets close to the full state. If for some reason your charger thinks the temperature is getting too high or the state is getting near full it dramatically slows the charging rate. Both of these could be erroneous interpretations of the battery data. Also, if you have an extended battery, make sure to use a Kernel that is compatible with extended batteries, like Hastarin 7.x.

Zythyr said:
I just tested the charging rate by connecting my HD2 to a stock charger from HTC which I borrowed from a friend. Charging was a lot faster.
Since I bought my HD2 used, the charger that came with it, is not the stock charger from HTC.
But I still don't understand what is causing the charging to be very slow.
Click to expand...
Click to collapse
Not all chargers are built the same. Some usb charger provide more juice while others provide less. Maybe your non stock charger came from a non smart phone...

Zythyr said:
Is it just me or everyone else that is experiencing a super long time in charging their phone to full battery? I am running the froyostone latest build and I have already followed all the guides in this forum to save battery life. The issue I am having is that it takes many hours to recharge the battery to full when connected to a wall charger.
It took 5 hours to go from 30% battery to 90%.
*no i wasn't charging the phone with the phone turn off*
Click to expand...
Click to collapse
Current Widget from the Market can tell you how many mA your phone is getting when it's charging.

this is just an approximation formula. a lithium ion battery charger is more sophisticated than this. it first brings battery voltage up to 20% safely (because any voltage below this is the harmful zone of operation), then it stuffs the battery at full capacity upto 80%. then in the 3rd stage, the current drops linearly with time.
over the past year, my stock battery gives me the following profile:
20-80% -> 1 hour (800-820ma constant, unless phone is awake)
80-100% -> 1 hour (800 -> 0ma)
by 100% i mean 0ma charge current. not 100% on the battery icon. you should be aware that the battery is still charging even after the indicator reaches 100%. but the current is insignificant (10-20ma)
even though the charger is rated at 5v 1A, it supplies only 820ma current at the maximum. this is normal. also for a lion battery the safe operating regions are around 20-90%. by safe i mean prolonging battery life. this roughly corresponds to 3.6v - 4.0v. avoid overcharging your battery frequently.
also someone mentioned current widget as a good approximate tool to study battery performance. you might also want to delete batterystats.bin and condition your battery once (i.e. fully discharge and fully recharge). this will force android to re-determine the new 0% and 100% levels. search the android forums for this.
hope this helps.
leehobin said:
Charging time = capacity of battery x 1,4 / charging current
HD2 stock battery= 1230mAh x 1,4 / 1000mA = 1,7 hours
Best
leehobin
Click to expand...
Click to collapse

silenced3 said:
this is just an approximation formula. a lithium ion battery charger is more sophisticated than this. it first brings battery voltage up to 20% safely (because any voltage below this is the harmful zone of operation), then it stuffs the battery at full capacity upto 80%. then in the 3rd stage, the current drops linearly with time.
over the past year, my stock battery gives me the following profile:
20-80% -> 1 hour (800-820ma constant, unless phone is awake)
80-100% -> 1 hour (800 -> 0ma)
by 100% i mean 0ma charge current. not 100% on the battery icon. you should be aware that the battery is still charging even after the indicator reaches 100%. but the current is insignificant (10-20ma)
even though the charger is rated at 5v 1A, it supplies only 820ma current at the maximum. this is normal. also for a lion battery the safe operating regions are around 20-90%. by safe i mean prolonging battery life. this roughly corresponds to 3.6v - 4.0v. avoid overcharging your battery frequently.
also someone mentioned current widget as a good approximate tool to study battery performance. you might also want to delete batterystats.bin and condition your battery once (i.e. fully discharge and fully recharge). this will force android to re-determine the new 0% and 100% levels. search the android forums for this.
hope this helps.
Click to expand...
Click to collapse
wow ! thanks alot !

Is it bad to let my charge over night overnight? I thought it would stop charging when it got full to avoid overhanging.
Sent from my HTC Inspire 4G

Since I have access to a a battery simulator and charger... the best way to recondition a battery is:
1. Create a low battery scenario by lowering the input voltage to just a hair above 2.7 volts (I had to create a shim to get to the battery receiver leads).
2. Boot with full 4.2 and in ClockWork remove battery stats
3. Drain and Charge battery to 4.2
I get enterprise email and I get a lot of mail daily that I have to read and respond to (150 or more -- no I don't respond to all of them), plus the phone calls, RSS reading and some texting plus a pic here and there and maybe a couple of you tube videos. I get more than 24 hours until the 15 % comes up. 50 hours would be nice but that did not even happen in my black berry with Edge only.
Mine improve 3 fold from sub 7 hours to 24 plus (yes I sleep late so probably the phone gets a 6 hour rest but the enterprise email and text is pushed down even then as I work with folks from Asia and Europe as well.

logdrum1 said:
Since I have access to a a battery simulator and charger... the best way to recondition a battery is:
1. Create a low battery scenario by lowering the input voltage to just a hair above 2.7 volts (I had to create a shim to get to the battery receiver leads).
2. Boot with full 4.2 and in ClockWork remove battery stats
3. Drain and Charge battery to 4.2
I get enterprise email and I get a lot of mail daily that I have to read and respond to (150 or more -- no I don't respond to all of them), plus the phone calls, RSS reading and some texting plus a pic here and there and maybe a couple of you tube videos. I get more than 24 hours until the 15 % comes up. 50 hours would be nice but that did not even happen in my black berry with Edge only.
Mine improve 3 fold from sub 7 hours to 24 plus (yes I sleep late so probably the phone gets a 6 hour rest but the enterprise email and text is pushed down even then as I work with folks from Asia and Europe as well.
Click to expand...
Click to collapse
How do I create a low battery scenario by lowering the input voltage to just a hair above 2.7 volts?

hiltun said:
Is it bad to let my charge over night overnight? I thought it would stop charging when it got full to avoid overhanging.
Sent from my HTC Inspire 4G
Click to expand...
Click to collapse
Yes, the "charger" that you plug into the wall is just a power supply, the actual "charger" is in the phone, and when it detects the battery is full it stops charging.

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.
Click to expand...
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.
Click to expand...
Click to collapse
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??
Click to expand...
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.

Battery Calibration process

Is this the definitive way to do it?
http://hemorrdroids.net/battery-calibration/
Those steps came from here, xda devs.
1. Run the device down until it turns itself off.
2. Turn it back on and wait for it to turn itself off again.
3. Remove the battery for 10 seconds.
4. Replace the battery, but leave the device off.
5. Charge the device until full and then for another hour.
6 **Root users only** Using a Terminal Emulator, type “su” enter, followed by “rm /data/system/batterystats.bin”
7. Run the device’s battery down until it turns itself off.
8 .Turn the device on and charge for at least 8 hours.
9. Unplug the device, turn off, then charge for another hour.
10. Unplug the device, turn on, wait 2 minutes.
11.Turn off again and charge for another hour.
12. Restart and use as normal.
Quite a performance! Does it preserve battery lifespan, or is it more to do with slowing down battery drain and does it really work?
He mentions 2 interesting things:
"Generally charge them before they get lower than 50%". I didn't know that, so it's actually better to charge more often and not let it drain down?
"USB charging is actually better for the battery and you may get up to 1 hours more standby time." So you gain an hour standby but it takes twice as long to charge the phone.

Nice manual
Will try it
Sent from my GT-I9100 using Tapatalk

Some will say that its complete nonsense .
Overcharge for 8 hours ??? how does the battery not turn charging off at 100%
Recharge 50% the accepted figure is not to go below 20% to often .
They may be right or wrong their are so many contrasting views on battery charging .
jje

Discharging battery and then reloading it fully, it's the normal procedure for battery calibration for almost all the devices in the world (including computers, etc.).
Step 8 to 11 seems quite a bit strange however.

hm, just seen a different way to calibrate the battery. basically, you drain the battery, take it out for a couple of minutes, put back in, then try to turn it on to make sure it's completely flat.
then you charge it fully, then boot to recovery and wipe battery stats then drain and fully charge. so... which one is more likely to be the better?

that guy also advises to repeat that 12 step, 1-2 day long tedious procedure "every month or so".
it is lunacy honestly speaking

does it work? did he died ?

LOL I dont understand .... I just read in another day that NEVER LET BATTERY GO LOWER THAN 15% and know I read "drain drain drain" Oh welll ...
I also thought that at 100% the charging process stops.

Although this thread is about battery calibration, these questions about battery charging always pop up.
Battery calibration is the process by which you set your device with your battery data.
Every single battery is slightly different. Although there are minimum stantards to every spec of the battery, each battery is different.
Calibrating your battery is nothing more than setting your phone to the real specs of your own battery (since the phone comes configured with the battery factory standards). For example, your phone may be set to use a battery which maximum charge is 1650 mAh, but your battery has a maximum charge of 1625 mAh. That may be within the acceptable factory standard, meaning you have a normal battery, but that also means that your phone will never indicate a 100% charge after you unplug the charger.
If you calibrate that hypothetical battery, you will "tell" your phone that its maximum charge capacity is actually 1625 mAh, meaning from that on your phone's battery indicator will be more accurate.
For that reason, it is necessary to fully discharge and fully recharge your battery for the calibration process, since your device must read the actual specs (minimum charge, maximum charge, charging current, etc) of the installed battery.
I don't know about how many times this full cicle (discharging and recharging) must be performed, but that is the reason why it must be performed for the calibration to succed.
A DIFFERENT THING is the normal discharging and charging process during normal use of the phone.
In this case, you should NEVER let your battery go under 20% and, what few people know, it also should never go over 95%. This stresses the battery and diminish its life time.
Also, and there's a lot of doubts about this, the lower the charging voltage, the slower the charging process, but the longer the battery life.
High charging voltages (like the one used by the charger sold with the phone, which is around 5V) stress the battery, diminishing considerably its life time.
That is true for all lithium-ion batteries!
Therefore it is better to charge your phone through USB (which uses around 4,3V) than to do it using the charger provided with the phone.
You may be asking "If the charging voltage of the charger provided by the manufacturer stresses the battery, why does the manufacturer provide such charger?"
For purely commercial reasons! Higher voltages mean shorter charging cycles, which please the consummer. Moreover, the battery capacity loss with the factory provided charger is around 15-20% a year (considering "normal" to "heavy" use). That is to say that after a year your battery will only reach 80-85% of the maximum charge it used to reach when it was new. And by that time your manufacturer expects you to consider buying a new phone, with more features.
Summing it up:
- calibration is just the process by which you "tell" your phone what the real specs of your battery;
- in normal use, charging your phone through USB is better than doing it with the manufacturer provided charger;
- try not to let your battery charge go under 20% nor above 95%;
- if you're interested, read more about it at batteryuniversity.com

Spin three times in clockwise direction with left middle finger on your nose while blinking your eyes with the phone plugged in.
Jump in the air 3 times.
Unplug phone.

Thats some messed up instructions.
Do you have any idea what kind of strain you're putting on the battery while doing all that?
All you're gonna get is some extra minutes, maybe an hour but is it really worth it because you're just reducing overall battery lifespan by doing that procedure over and over.
Specially when you constantly keep the battery at 4200mV (full charge) for a long time. You're practically killing it by overcharging.
Transmitted from a Galaxy far far away via XDA telepathy.

m2smoe said:
Spin three times in clockwise direction with left middle finger on your nose while blinking your eyes with the phone plugged in.
Jump in the air 3 times.
Unplug phone.
Click to expand...
Click to collapse
that made me chuckle

Never done a calibration on a battery and most of the time i even didn't let battery to discarge very much and then load it again. Never had a problem with battery life it last how long it should last every time and i've used that battery for years. So the battery "calibration" are kinda useless.

Matriak31 said:
that made me chuckle
Click to expand...
Click to collapse
Well then, my job here is done

m2smoe said:
Well then, my job here is done
Click to expand...
Click to collapse
it is indeed...i should follow you just to have more laughs like that cheers

RenatoN said:
Although this thread is about battery calibration, these questions about battery charging always pop up.
Battery calibration is the process by which you set your device with your battery data.
Every single battery is slightly different. Although there are minimum stantards to every spec of the battery, each battery is different.
Calibrating your battery is nothing more than setting your phone to the real specs of your own battery (since the phone comes configured with the battery factory standards). For example, your phone may be set to use a battery which maximum charge is 1650 mAh, but your battery has a maximum charge of 1625 mAh. That may be within the acceptable factory standard, meaning you have a normal battery, but that also means that your phone will never indicate a 100% charge after you unplug the charger.
If you calibrate that hypothetical battery, you will "tell" your phone that its maximum charge capacity is actually 1625 mAh, meaning from that on your phone's battery indicator will be more accurate.
For that reason, it is necessary to fully discharge and fully recharge your battery for the calibration process, since your device must read the actual specs (minimum charge, maximum charge, charging current, etc) of the installed battery.
I don't know about how many times this full cicle (discharging and recharging) must be performed, but that is the reason why it must be performed for the calibration to succed.
A DIFFERENT THING is the normal discharging and charging process during normal use of the phone.
In this case, you should NEVER let your battery go under 20% and, what few people know, it also should never go over 95%. This stresses the battery and diminish its life time.
Also, and there's a lot of doubts about this, the lower the charging voltage, the slower the charging process, but the longer the battery life.
High charging voltages (like the one used by the charger sold with the phone, which is around 5V) stress the battery, diminishing considerably its life time.
That is true for all lithium-ion batteries!
Therefore it is better to charge your phone through USB (which uses around 4,3V) than to do it using the charger provided with the phone.
You may be asking "If the charging voltage of the charger provided by the manufacturer stresses the battery, why does the manufacturer provide such charger?"
For purely commercial reasons! Higher voltages mean shorter charging cycles, which please the consummer. Moreover, the battery capacity loss with the factory provided charger is around 15-20% a year (considering "normal" to "heavy" use). That is to say that after a year your battery will only reach 80-85% of the maximum charge it used to reach when it was new. And by that time your manufacturer expects you to consider buying a new phone, with more features.
Summing it up:
- calibration is just the process by which you "tell" your phone what the real specs of your battery;
- in normal use, charging your phone through USB is better than doing it with the manufacturer provided charger;
- try not to let your battery charge go under 20% nor above 95%;
- if you're interested, read more about it at batteryuniversity.com
Click to expand...
Click to collapse
You should post the source for your info, cause I am seeing a lot of incorrect information in here.
If you guys want to learn about your battery, visit the site Battery University

The OEM replacement battery is worth about $10.
Save yourself the stress....use it...charge it when you need to...if the battery ever fails cough up $10.
Sent from my GT-I9100 using XDA App

The way I would calibrate my batteries is a bit different. Lithium ion batteries don't need to be drained then charged to full AFAIK, and I even remember reading somewhere that draining it is actually only for NiCad batteries. It used to be relevant when phones were using NiCad but not anymore.
Read: http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
As such I have read that the universal way to 'calibrate' batteries is by charging to full, using for a couple of mins and charging again.
What I have been doing is:
1. Charge to full when phone is switched off (doesn't matter if it's from 0% or 99%).
2. Switch on the phone, use for 5 mins.
3. Switch off then charge until full.
4. Repeat step 2 once more
That's it! It seems pretty simple but it seems to have worked for me.

The way i do it is different. Firstly i have the battery calibration app from the market by Nema..then i fully charge my phone and when it says its fully charge i go into the app. There it gives me the instructions on how to calibrate...First i wait till i charge the phone without any interruptions. then click on the app and wait til the battery goes to 4200MV and then i press the calibrate button and then the app does it for me. Then i drain the battery again without any interuptions or breaks during that time and then charge it again once battery dies down and thats it.
there are so many ways being touted on the forums you really dont know which one to go for...but whatever works for each person then who are we to tell someone different just thought i share that

If my battery dies, or gets significally lower capacity after 1 or 2 years of usage, I'll just buy a new one if I plan to keep the phone longer.. Going through these rituals and painstakenly monitor my battery % so that it never goes below 20 % or above 95 % is just not worth it.. Doesn't increase the life THAT much anyway.. I use the phone until I hear the beep for low batt, and from there until I have a charger available.. Most of the time it's before it reaches 10 %, thats good enough for me.. Once in a while it might even go so far that it dies.. Then I charge it till it says 100 %.. Most of the times I plug it when going to bed, and let it charge over night.. This is normal usage and what the battery should be designed to handle, and so far it does..

Bad Charging

Hi,
I own a Galaxy Not 10.1 2014 Wifi (SM-P600) currently running RessurectionRemix (https://forum.xda-developers.com/ga...om-resurrection-remix-n-sm-p600-wifi-t3606313)
Last year I replaced my battery with a new Samsung Original battery. But now i cant get the battery to charge to 100%. It always stops at ~45%.
If i check the charge current with the app Ampere it says maximum 450mA. It makes no difference which charger or cable I use.
Because of the loose fit of the MicroUSB connector I also replaced the connector unit.
Ampere also says that the battery is in good condition.
I also measured the battery voltage using a multimeter directly on the terminals of the two cells. Both cells had around 4.2V when the tablet stopped charging and showed a batterylevel of ~45%.
Is there anything I can do to get 100% and a higher charge current. Because now even if I plug the tablet into the charger the battery keeps draining while using it.

HamburgerJungeJr said:
Hi,
I own a Galaxy Not 10.1 2014 Wifi (SM-P600) currently running RessurectionRemix (https://forum.xda-developers.com/ga...om-resurrection-remix-n-sm-p600-wifi-t3606313)
Last year I replaced my battery with a new Samsung Original battery. But now i cant get the battery to charge to 100%. It always stops at ~45%.
If i check the charge current with the app Ampere it says maximum 450mA. It makes no difference which charger or cable I use.
Because of the loose fit of the MicroUSB connector I also replaced the connector unit.
Ampere also says that the battery is in good condition.
I also measured the battery voltage using a multimeter directly on the terminals of the two cells. Both cells had around 4.2V when the tablet stopped charging and showed a batterylevel of ~45%.
Is there anything I can do to get 100% and a higher charge current. Because now even if I plug the tablet into the charger the battery keeps draining while using it.
Click to expand...
Click to collapse
This is probably not what you're going to want to hear, but I faced the exact same issue and decided to power cycle the battery (drain it fully, charge it up to 100%). I got to the drain fully part and then it wouldn't charge anymore. I had tried the same thing as you with multiple cords and tried charging from a couple of different power banks as well.
My advice if you love your device like I do...buy another battery and keep it plugged in until you can swap it out with a new one. Once it hit 1% it was gone for good. This happens to me every 1-2 years...I've changed the battery in mine 3 times. Personally I think it's the OEM replacement batteries that are garbage. Next time I'm going to buy the newpower99 one and see if it lasts longer.
TLDR: keep it plugged in, buy a new battery, replace ASAP.
If you do get it working though I would love to hear your solution in case it happens again!

Well I did find a "solution".
It seems that the power management is quite bad on the Samsung devices, which means it has to be reseted from time to time. I could fix it partially by disconnecting the battery for ~10 Minutes and reconnecting it.
Now I got 75-80% charge and a reasonably charge current. But now the low voltage detection seems to be a bit off. At ~25% the screens stars flickering and it turns off after a short time.
I found this hint in the comments of a YouTube video about replacing the battery or charging connector.

HamburgerJungeJr said:
Well I did find a "solution".
It seems that the power management is quite bad on the Samsung devices, which means it has to be reseted from time to time. I could fix it partially by disconnecting the battery for ~10 Minutes and reconnecting it.
Now I got 75-80% charge and a reasonably charge current. But now the low voltage detection seems to be a bit off. At ~25% the screens stars flickering and it turns off after a short time.
I found this hint in the comments of a YouTube video about replacing the battery or charging connector.
Click to expand...
Click to collapse
I will definitely try that out thank you! Mine does that at around 10% and there are times the battery will say it's at 30% then drop to <5% in a few minutes. I just leave it on the charger over night now which I know isn't the best for battery life but at least it keeps it on when I use it
cheers

Battery management is voltage based. The Android Coulometer mainly has to filter short voltage drops caused by high cpu load.
If the Coulometer begins to show sudden changes in capacity and causes premature shutdowns, you can flash the coulometer firmware, if you're running stock rom. Reinstalling stock rom in Download Mode should also help.
There are only few sources on the net dealing with this coulometer thing and only for certain devices.
But if you do nothing, the capacity jumps will fade away with time. It took months on an old tablet of mine, but the period of time may depend on the time since the last full factory reset or system recovery. And my (and your) Note are older today than this tablet back then...
Then there's always real cable and battery isdues.