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.
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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
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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..

Constant usage battery life

From what I have seen, most battery life comparisons/stats are usually done with the phone in standby/screen off majority of the time.
I decided to do it the other way.
Last night to this morning:
I tried charging my battery to 100% but time constraints only had me charge it to around 84% (late for work).
I don't use/have a charger at work nor do I have one in my car. I work 8 hours straight (11pm - 7am) and I almost always stream pandora the entire time.
I am using the seidio extended battery and the only thing that stays off is wifi when I am not within range of any kind of open network (starbucks) or my own saved connection list. 4g/3g, gps, and background data are constantly on.
So, from 84% left the house and started streaming pandora in the car. Get to work about 15 minutes later with no interruption in streaming (just turned the volume down). I do shut off my screen while streaming when I put the phone in my pocket.
Surfed the web, watched some youtube videos, checked gmail and facebook (which auto sync about every hour and gmail notifies me of every single email I get), and played some games here and there (nothing great) throughout the night.
Basically my intent was to never let the phone sit and do nothing. The entire time pandora was streaming (browsing the net and streaming, checking gmail/facebook and streaming) but youtube would always stop pandora.
Got 8 hours of constant use. I don't want to say moderate/light/heavy as that scale changes from person to person. Moderate for one person may be heavy for the next.
I charged the battery in the phone because I don't have an external charger for it. Although I may get one because my charging method still involves me taking the battery out of the phone.
No task killers, no setcpu (I am rooted), no custom rom (from the dev forum).
I am using bakedsnack kernel #4, launcherpro, and I have personally uninstalled a crap load of stuff (even htc sense and rosie altogether).
My opinion is that all these gimmicks that we have to go through to get good battery life while in standy are not necessary. What is necessary is for the charging system in the evo to be revamped. This is my own opinion, but I think the charging system in the evo skips stage 2 of the charging process http://www.batteryuniversity.com/partone-12.htm which is why (this is what I think, I am no expert) so many people see the sudden drop from 100% down to whatever shortly after they unplug their charger.
It kind of makes sense as to why some people who charge their stock batteries in the ebay externals get better battery life, it's because they are actually being charged properly.
Again, this is just my opinion and I am in no way an expert on this. Just disclosing my experience and observations of my phone and it's behavior. Take from it what you will.

That's pretty amazing dude. Me personally would consider your use for this test to be pretty heavy. I'm more than impressed to see 37% battery life. And from what I've been reading up on the external charger is definitely the way to go. Although it's quite a pain to have to charge our evos like this just for maximum battery life. Hopefully in the future releases of phones we won't have tis do things like this. As mentioned in another post the switching of the battery to charge it will eventually make the back door loose or maybe even break sooner than planned, which is a problem for people who don't have extra doors. I guess it's not a bad investment to buy extra doors though.
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lovethyEVO said:
From what I have seen, most battery life comparisons/stats are usually done with the phone in standby/screen off majority of the time.
I decided to do it the other way.
I am using the seidio extended battery
My opinion is that all these gimmicks that we have to go through to get good battery life while in standy are not necessary.
It kind of makes sense as to why some people who charge their stock batteries in the ebay externals get better battery life, it's because they are actually being charged properly.
Click to expand...
Click to collapse
Here is my take and i edited your post down to the points i am discussing.
First I like the fact you realize most battery tests and many of the people getting ridiculous battery life are idle most of the time (even if they say they are moderate use normally they have 1-3 hours of moderate use out of the 30 hours battery life they claim). I think showing actual usage time is much more impressive.
Now if you are going to do a battery post and talk about opinions and what your battery life is ... i don't suggest using an extended battery. you show that over aprox 8 hours of use (wont classify it as heavy moderate etc since you didnt) you lost about 50% the problem here is the extended battery from seidio has a much larger capacity then your standard htc battery that comes with evo (even if it doesnt actually have the 3500mah it is still a lot more). On a est i did i could play a movie on a stock battery for just over 5 hours before the battery drained using nothing but the stock install of a rom and without changing settings to turn things off etc. So in my opinion the battery life you are showing is actually a little low for that battery but that not really the point.
now as for the evo charging incorrectly. the reason why peoples batteries drop quickly the first 20-30 minutes (for most who have a correctly calibrated "battery") is because EVO doesn't have a trickle charge. this doesnt mean the evo isnt charging the battery correctly. the idea behind not having a trickle charge is it helps prolong the life of the battery it self at the cost of 0-10% charge depending on where it is when you take it off the charger.
While i personally would rather have the trickle charge and have to buy replacement batteries more often. it isnt that the evo charges incorrectly it. They jsut made the choice to try to make the battery itself last as long as possible at the cost of some battery use time depending on when you take it off the charger.

These are my latest seidio 3500 numbers with correct battery conditioning. Going to try and duplicate these numbers. Most of about 10 hours was slacker and pandora. This was from 100 to 14 percent on 3500 seidio. Pics for your pleasure and debate. I was able to get another 8 hours standby from this point and hour of lets golf before battery died. That was my 2nd conditioning of the battery. Going on 3rd full slow trickle charge up now. The trickle charge on battery wall charger takes about 12 hours wtf but worth it. I just use my cheap china 3000mah to cover the time.
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omegasun18 said:
Here is my take and i edited your post down to the points i am discussing.
First I like the fact you realize most battery tests and many of the people getting ridiculous battery life are idle most of the time (even if they say they are moderate use normally they have 1-3 hours of moderate use out of the 30 hours battery life they claim). I think showing actual usage time is much more impressive.
Now if you are going to do a battery post and talk about opinions and what your battery life is ... i don't suggest using an extended battery. you show that over aprox 8 hours of use (wont classify it as heavy moderate etc since you didnt) you lost about 50% the problem here is the extended battery from seidio has a much larger capacity then your standard htc battery that comes with evo (even if it doesnt actually have the 3500mah it is still a lot more). On a est i did i could play a movie on a stock battery for just over 5 hours before the battery drained using nothing but the stock install of a rom and without changing settings to turn things off etc. So in my opinion the battery life you are showing is actually a little low for that battery but that not really the point.
now as for the evo charging incorrectly. the reason why peoples batteries drop quickly the first 20-30 minutes (for most who have a correctly calibrated "battery") is because EVO doesn't have a trickle charge. this doesnt mean the evo isnt charging the battery correctly. the idea behind not having a trickle charge is it helps prolong the life of the battery it self at the cost of 0-10% charge depending on where it is when you take it off the charger.
While i personally would rather have the trickle charge and have to buy replacement batteries more often. it isnt that the evo charges incorrectly it. They jsut made the choice to try to make the battery itself last as long as possible at the cost of some battery use time depending on when you take it off the charger.
Click to expand...
Click to collapse
50% loss over 8 hours of near constant use (my awake time shows that it did manage to sleep somehow even though I streamed pandora constantly) on any battery (extended or not) is actually a good thing as it shows that even with the phone fully bogged down (almost all radios on) it can last a full work day (which is what most people are concerned about).
I still believe the evo does not charge the batteries correctly and it is not solely related on the absence of a trickle charge.
Again, from my observations over the course of the past three weeks. I started with what my battery was calibrated to according to the phone. Let it drain down to about 15% (according to the phone) and wiped the battery stats and did a different charging method from the htc "rain dance".
Here is where my opinion of the evo not charging properly comes into play.
From 15% to 100% charge (charged while phone and screen are on to monitor voltage, temp, mA draw, etc.) took about an hour +/- a couple minutes. As soon as the led turned green (yes, I literally sat at my phone watching the percent slowly rise) I unplugged the charger and noted the resting voltage level and percent (according to three seperate battery status applications). Once noted, I powered down the phone. After the screen completely shut off I removed the battery and tested the voltage. I did this for my own information because I wanted to verify the phone itself was actually reporting the voltage levels correctly. It was.
Now, recall that I had just charged the phone to 100% and had wiped battery stats prior to charging.
Replaced the battery back into the phone and powered up. Normally people see a jump in battery percentage when they power down and back up. Not in my case. To my amazement, the evo reported my battery as being at 78% charge level. So I went from being 100% charged down to 78% percent charge all from powering down, removing the battery, checking voltage, and then replacing battery and powering up. Time to power down, remove, check voltage, replace and power up is somewhere around the one minute mark +/-.
Again, referencing the link I provided earlier about charging li-ion batteries, the evo seems to skip stage 2 of the charging process which usually results in about a 70% charge (according to the link).
Charged it again from the 78% mark to 100% and the charging time took just over an hour to get back to 100%. Same routine, check voltage on phone, power down, remove battery, check voltage on mmeter, replace battery, power on, check levels.
Second time around I dropped from 100% charge to about 89%. Voltage levels were always accurate. Charged again and took about another hour +/- and finally achieved a charge to where it would not fall or rise between a power down (97% seems to be my cap which is fine since I don't want to truly charge the battery to 100%).
To test the discharge rate I tried my best to keep the battery running condition identical for each discharge run.
I monitored the battery temp, cpu temp, battery voltage, amp draw, and cpu load.
Streaming only pandora and nothing else I usually managed to keep the amp draw to around 300 - 360mA with the screen on. This was my way of measuring the discharge rate without access to equipment that could give the battery a steady discharge load.
Every time the percentage dropped one I would note the volts, temps, amp draw and cpu load. Across the board temps and cpu load remained close to constant as the phone wasn't doing too much multitasking.
At this point, I have about 4 full voltage readouts from 100% down to 15%. Without wiping battery stats, if I charge the phone with my method (charge to 100%, power down, remove battery, replace battery, power up and recharge) my past voltage readouts coincide with my battery readouts on the phone (87% falls within a certain voltage range and so on) but if I just charge the battery until the phone says it's 100% then the readouts on the phone no longer fall within my past readouts until I go back to my charging method. This tells me that if I let the evo charge the battery the way it is programmed to (hardware or software) then it is not actually charging the battery to its full potential (not necessarily 100%).
Across the board the cpu load and the temps rarely drastically changed as it wasn't running multiple tasks at once. This is just my own observations and tests that I did/started doing for my own intellectual reference.
I have done the same charging method with my wife's evo and stock battery (1500 htc oem). I wiped her stats but only managed to get two full voltage readouts with her phone. She has stated that her battery does last longer than before and she is only rooted to remove bloatware. She is running stock rom, stock kernel, no task killers, no memory managers, and her radios and settings are close to mine (she gets more mail and facebook notifications than I do).
Again, this is just my opinion and personal observations. I did this solely because I got tired of having to constantly turn things on and off just to use them. My past phones never had this problem and I don't think the evo should have to be babied just to get good battery life. I still believe it all lies in the charging system of the phone and not necessarily the battery (extended versus stock).

Hey, what battery conditioning did you guys do? There's a ton of different suggestions and I am wondering if one or two have finally been proven to not be placebo.

I decided to do the HTC charging method when I changed roms to cm6. I went into hboot after and wipe stats. Turned on and took about 20 minutes to get to 98% using internet. Anyways I let phone die. Plug it in and I have system monitory with history monitoring. So I go to bed, and wake up to expect 100%. Nope 80%. Checked the monitor and trickled from 80% to 70% for 2 whole hours. I did the HTC thing again for full charge. Repeated. Only charges to 80%!!!! I changed roms. Same thing.
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martyzidek said:
I decided to do the HTC charging method when I changed roms to cm6. I went into hboot after and wipe stats. Turned on and took about 20 minutes to get to 98% using internet. Anyways I let phone die. Plug it in and I have system monitory with history monitoring. So I go to bed, and wake up to expect 100%. Nope 80%. Checked the monitor and trickled from 80% to 70% for 2 whole hours. I did the HTC thing again for full charge. Repeated. Only charges to 80%!!!! I changed roms. Same thing.
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Click to expand...
Click to collapse
Your situation also points to my opinion that the charging system on the evo does not charge correctly. I am also thinking that the battery stats dont play a huge role but I still jave more monitoring to do.

I also prefer the constant-use benchmarks, and did one myself as well. Charge to 100% and then stream DI.fm using XiiaLive (96Kbps MP3) through WiFi (router in same room) + full brightness + screen ON (no timeout). My poor Evo lasted 3:55 before forced shutdown . Btw, running Fresh v3.1.0.2 with netarchy v4.1.8-cfs, no SetCPU or any other "battery saving" tools.

frifox said:
I also prefer the constant-use benchmarks, and did one myself as well. Charge to 100% and then stream DI.fm using XiiaLive (96Kbps MP3) through WiFi (router in same room) + full brightness + screen ON (no timeout). My poor Evo lasted 3:55 before forced shutdown . Btw, running Fresh v3.1.0.2 with netarchy v4.1.8-cfs, no SetCPU or any other "battery saving" tools.
Click to expand...
Click to collapse
I am at work now and when I get home I plan on charging the stock battery as best as I can and doing another constant use run to satisfy the crowd who run the stock battery.

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?
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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?
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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.
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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..

TF300 Battery / Charging discussion thread

Please discuss everything related to battery or charging in this thread

Great! So I got myself thinking about the dock charging situation: Why is it so that the dock charges the pad instead of the pad drains the dock?
In my opinion it is better (or more logical) that the pad sees the dock as rendundary battery and drains it at need. F.e. the pad runs till 50% then drains the dock completely dry and then uses the rest of its 50%.
Btw: I wonder if the dock charging logic is realized with hardware or software by Asus...

UncleManuel said:
Great! So I got myself thinking about the dock charging situation: Why is it so that the dock charges the pad instead of the pad drains the dock?
In my opinion it is better (or more logical) that the pad sees the dock as rendundary battery and drains it at need. F.e. the pad runs till 50% then drains the dock completely dry and then uses the rest of its 50%.
Click to expand...
Click to collapse
Um, at the end of either scenario, aren't you left with the same overall usage time and 2 dead batteries?
And isn't your preferred scenario almost exactly what happens in real world use?

what widgets drain battery?
i know widgets like weather, email, news drain battery because they need to update, use internet connection, so i don't use them to save battery.
but what about "offline" widgets like google play music, clock,... do they drain battery too? they don't update information using internet, but they do update "offlinely" - i mean, for example: google play music, now it shows the song "A", then you open the app and skip to song "B", when you go back to homescreen the widget will show song "B". so it has to update, does this drain the battery?
lol i guess i worry about battery too much, and just figured out that i created the thread "should i use battery saver app", i should have post it in this thread, sorry

and does leaving the charger plugged in to the wall outlet when not charging the tablet harm the charger or waste electricity?

nooktablet said:
and does leaving the charger plugged in to the wall outlet when not charging the tablet harm the charger or waste electricity?
Click to expand...
Click to collapse
CHARGING/DISCHARGING TIP:
LET THE DEVICE (THIS GOES FOR ANYTHING WITH A RECHARGABLE BATTERY) FULLY CHARGE.
UNPLUG, THEN LET IT FULLY DISCHARGE...ALL THE WAY!-- JUST LET IT DIE WHERE IT WONT TURN ON.
Doing this will increase battery time, decrease battery wear/tear, possible damage done by overcharging.
Do this on a regular basis, and youll start to see it will last longer then 10hrs
Because of this, i run alot of widgets, on performance mode, i have around an extra 30MIN, so 10hrs 30min is my batterys life.
*leaving the device plugged in,charging when its full, is bad!
*using the device, while charging, burns up the battery, youll notice it getting hot.

Picked this tablet up the other day. I noticed that when I took it in the car and plugged it's charging cable into my car usb charger (kengsington powerbolt) that it did not show that it was charging. Is this common? The charge has worked for all the phones I've plugged into it.

CyberdyneSystems said:
CHARGING/DISCHARGING TIP:
LET THE DEVICE (THIS GOES FOR ANYTHING WITH A RECHARGABLE BATTERY) FULLY CHARGE.
UNPLUG, THEN LET IT FULLY DISCHARGE...ALL THE WAY!-- JUST LET IT DIE WHERE IT WONT TURN ON.
Doing this will increase battery time, decrease battery wear/tear, possible damage done by overcharging.
Do this on a regular basis, and youll start to see it will last longer then 10hrs
Because of this, i run alot of widgets, on performance mode, i have around an extra 30MIN, so 10hrs 30min is my batterys life.
*leaving the device plugged in,charging when its full, is bad!
*using the device, while charging, burns up the battery, youll notice it getting hot.
Click to expand...
Click to collapse
I believe you are mostly right, but letting the battery constantly drain and recharging from 0-10% makes it work really hard and it makes in turn the life of the battery less. But in terms of life we are talking about a couple of mins less every half a year or so, since these devices get replaced by new ones every 1-2 years I guess it is ok.
If you want to sustain the most battery life just charge it from time to time when it gets lower than 40%. If you are having problems with battery duration, charge to 100% let it discharge completely then charge again until 100% without interruption. I do the full discharge and charge every month or so.

CyberdyneSystems said:
CHARGING/DISCHARGING TIP:
LET THE DEVICE (THIS GOES FOR ANYTHING WITH A RECHARGABLE BATTERY) FULLY CHARGE.
UNPLUG, THEN LET IT FULLY DISCHARGE...ALL THE WAY!-- JUST LET IT DIE WHERE IT WONT TURN ON.
Doing this will increase battery time, decrease battery wear/tear, possible damage done by overcharging.
Do this on a regular basis, and youll start to see it will last longer then 10hrs
Because of this, i run alot of widgets, on performance mode, i have around an extra 30MIN, so 10hrs 30min is my batterys life.
*leaving the device plugged in,charging when its full, is bad!
*using the device, while charging, burns up the battery, youll notice it getting hot.
Click to expand...
Click to collapse
i heard many people say letting it fully discharge (use until it turns off) and charge back to 100% will harm the battery, (or battery's lifespan). i read many guides online and all of them say this. i asked other people in other forums and they said the same thing.
but i guess you're right that it will improve battery life, in about a half year or a year (depending on how often you charge), then the battery won't be able to hold a long charge anymore. it won't be a problem it you plan to change/upgrade your device next year anyway.

The best battery tips that I use
Remove unnecessary widgets
Use a clean rom
Set your CPU to ondemand and put it on lowest frequency
Turn of wifi when you are not using your device
If you don't need your device for longer than an hour, turn it off
I use it for about an hour during the mornings up until dinner, then it gets a workout and I have never had my tablet die on me, or a need to rush for a charger.