Develop Bugs

Battery charging BUG

Hi every one,
As far i know, there is a BUG on every official ROM for European GSM Touch Pro2.
When your battery get full charged and keeping it plugged to the wallcharger, then your Pro2 start taking the power from your battery and NOT from the charger.
This can be checked by yourself and you will see that even with it connected, the battery in running down charge, till you unplug it and plug it again after some minutes/seconds.

Yeah, I have noticed it as well. Anyone have a solution?

Not a bug. LiPoly's do not like being trickle charged, therefore the charger turns off.
I have not verified it on the TP2 but I suspect that if you let it sit long enough the battery level would drop to some level and the charger would charge it back to 100%.

This is a rather good new if it can manage battery loads cycles...

khaytsus said:
Not a bug. LiPoly's do not like being trickle charged, therefore the charger turns off.
I have not verified it on the TP2 but I suspect that if you let it sit long enough the battery level would drop to some level and the charger would charge it back to 100%.
Click to expand...
Click to collapse
It oughta turn the charger off and run the device from the mains, though, not from the battery. Is it doing that?

godefroi said:
It oughta turn the charger off and run the device from the mains, though, not from the battery. Is it doing that?
Click to expand...
Click to collapse
No it is NOT doing that, so to me it is a BUG.

just thought i would add this
for some reason on saturday i charged my phone via usb/pc and it lasted less than 24 hrs
so on sunday i drained it and charged it vis the plug
its still going noe
72 hrs 23 mins in stanby 30 mins talk and 4 hrs 7 mins use since 17.43 on 18/10/09
is never been this good so i thought it may be the new rom

http://www.batteryuniversity.com/partone-21.htm
Lithium-ion
(Li-ion)
Do charge the battery often. The battery lasts longer with partial rather than full discharges.
Do not use if pack gets hot during charge. Check also charger.
Charge methods: Constant voltage to 4.20V/cell (typical). No trickle-charge when full. Li-ion may remain in the charger (no memory). Battery must remain cool. No fast-charge possible.
Rapid charge = 3h
also i have read some where on xda that once it reaches 100% it'll stop charging

godefroi said:
It oughta turn the charger off and run the device from the mains, though, not from the battery. Is it doing that?
Click to expand...
Click to collapse
You know of any other modern phone that runs off the mains without the battery? None of my last three phones would without the battery.

khaytsus said:
You know of any other modern phone that runs off the mains without the battery? None of my last three phones would without the battery.
Click to expand...
Click to collapse
My Kaiser will. It turns off when you pull the battery, but you can turn it right back on.

Every one is talking about battery and it's components but no one speaks about that with charger pluged in, it should supply power and by pass the battery once it is fully charged like others models do.

sounds like you all need to do warranty exchanges for that lol

Tallpap said:
sounds like you all need to do warranty exchanges for that lol
Click to expand...
Click to collapse
No, what we need is that HTC do what we paid for.

User22 said:
Every one is talking about battery and it's components but no one speaks about that with charger pluged in, it should supply power and by pass the battery once it is fully charged like others models do.
Click to expand...
Click to collapse
http://forum.xda-developers.com/showthread.php?t=571606 some people here probably would help
xnifex said:
it's true, once the TP2 hits 100% it stops charging the battery & the usage time will kick in.
Click to expand...
Click to collapse
and on this thread http://forum.xda-developers.com/showthread.php?t=573037&page=4 which a guy says
mattdoyal said:
Just tried my TP2 without the battery and plugged, didn't power on. Why would they take away the ability to power on while plugged in but with the battery removed?? This was and would be a great troubleshooting step. Hey HTC, start building our phones with this option!!
Click to expand...
Click to collapse
i hope this helps

Have in mind that once the battery is fully charged, it never go to charge again till you unplug the cable of your wall/car charger... so what will hapen then???

hello anyone know about the issue with the battery ok when i charge my euro tp2 all night and when i go to start>settings>all settings>system>power i then click on the infomation tab and under last full charge i get "not applicable" and get 0 hours and 0minute for the rest
im running the offical htc 6.5 rom

To me this sounds CRAZY. So people are saying that when the device is fully charged it starts to use its battery, thats just crazy... So basically charging it overnight leaves you with "almost" full battery in the morning...
I havent noticed anything out of the ordinary, and every morning when I come and take my device from the charger the charging light is green (opposed to the orange when started charging) and the battery shows to be 100% full.
I will check this again in the morning as I havent really paid 10000% attention to it, but I think I would have noticed the weird behaviour…

noticed this since day 1. my dash didnt do this. i did notice that a soft reset will resume the charge.

This is normal behavior for battery powered devices.
When it's plugged in, the charge circuit charges the battery.
The device itself always runs off the battery when it's available, this is why some devices won't power on without the battery installed, and many devices won't power on with a failed battery installed.
Laptops do the same thing, though they can switch to AC only without losing their state.
It's a holdover I think from when electronics couldn't switch between power sources fast enough to not lose anything (I remember the original game boy would reset no matter what if you tried to switch between batt and AC). It's possible that cell phones can't make this transition since there isn't really extra space to stuff in the bits that allow this (some large-ish caps).
I've also heard that this reduces wear on the electronics, because the voltage is more reliable, but I've never seen that documented.

kay7 said:
The device itself always runs off the battery when it's available, this is why some devices won't power on without the battery installed, and many devices won't power on with a failed battery installed.
Laptops do the same thing, though they can switch to AC only without losing their state.
Click to expand...
Click to collapse
I don't think this is true for (modern) laptops. All the macbooks and thinkpads that I've owned had a feature that if you plug it in while the battery is above X% (usually around 96) it will not charge. It even gives a message saying "Not Charging" in the battery status. The battery percentage then stays constant no matter how long I use the laptop, so it is not DIScharging either. Therefore it must be running from AC. If it can do that, I doubt they would have it run off the battery as soon as it is charged to 100% on a full charge cycle. I think any time AC is plugged in, a modern laptop will run from AC rather than battery, regardless of whether it is currently charging the battery. However, that's just my theory from personal observations.

[HOWTO] Battery meter accuracy

I noticed something about the battery meter.
If you power on your phone when the charger is plugged in, the battery meter shows a higher value.
If you power on your phone when no charger is connected, the battery meter shows a lower value.
And these values stay for as long as your phone is not rebooted. My guess is, the value without charger plugged in (lower value) is more accurate.
So, if you want to make your battery meter more accurate, try this:
- Disconnect your phone from the charger
- Power off the phone
- Power on the phone again (phone must be disconnected from charger)
- After phone has booted into Android, plug the phone into USB/charger to charge it again
If you could try this out and see if the observation is always true, then maybe we should make this procedure standard to get a more accurate battery meter reading.

So this may have caused the fact that my phone keeps telling me, while charging, the battery is fully charged however it says 95% as soons as its unplugged

Power off the phone and connect charger while it's off, wait for the 100% sign on the fully green battery, then unplug the cord and connect it again, you can do this a couple of times. And resetting the battery stats should also help in some way.

opica said:
Power off the phone and connect charger while it's off, wait for the 100% sign on the fully green battery, then unplug the cord and connect it again, you can do this a couple of times. And resetting the battery stats should also help in some way.
Click to expand...
Click to collapse
What I'm suggesting is a bit different.
Power off phone.
Power on phone again, without plugging anything in.
After phone has booted, plug in charger.
EDIT: I notice this difference in battery meter reading tends to happen only with the *real* charger, and not when connect to a USB port on a PC.

That is right hardcore. This also refers to post-flashing boot.
I always disconnect device as soon as flashing procedure completes.

hardcore said:
I noticed something about the battery meter.
If you power on your phone when the USB charger/cable is plugged in, the battery meter shows a higher value.
If you power on your phone when no USB charger/cable is connected, the battery meter shows a lower value.
And these values stay for as long as your phone is not rebooted. My guess is, the value without USB plugged in (lower value) is more accurate.
Click to expand...
Click to collapse
Hey,
Heres whats happening:
Lithium-ion batteries dont like it when you charge them while full. It wears them down. So to preserve batterylife it charges untill full, then stops charging completely. When it droppes down to far, it'll charge again for a bit. The phone will show full, in reality it'll be a little less. When you unplug it will drop down quickly to a more precise value. Bump-charging (disconnect, reconnect charger) works, however you are wearing the batterylife down. Could be you dont care, so it'll be youre own choice.
Older phones do not do this. They charge till full, then trickle power continuesly so it'll always be full when disconnected.
Hope this helps.

weirder said:
Hey,
Heres whats happening:
Lithium-ion batteries dont like it when you charge them while full. It wears them down. So to preserve batterylife it charges untill full, then stops charging completely. When it droppes down to far, it'll charge again for a bit. The phone will show full, in reality it'll be a little less. When you unplug it will drop down quickly to a more precise value. Bump-charging (disconnect, reconnect charger) works, however you are wearing the batterylife down. Could be you dont care, so it'll be youre own choice.
Older phones do not do this. They charge till full, then trickle power continuesly so it'll always be full when disconnected.
Hope this helps.
Click to expand...
Click to collapse
I'm not talking about the usual Li-ion full-charge effects. Also it may not be true that other phones don't do this. For sure, many laptops do this - after the battery charges to 100%, they won't charge the battery until it decreases to a certain level, say 95%.
I'm referring to the difference in battery meter reading if u boot the phone while connected to the wall charger, vs booting the phone when it's disconnected from the charger.

What you say is right, I am used to power OFF my phone & charge it at night, & when I get up, switch it ON while still plugged in. I must make it a point to remove the cable before I switch ON.

I noticed this many months ago and it persists even after flashing many different firmwares. It actually comes in handy some times. For instance when my battery is running low and i need to step out i simply plug in the charger, power off then power back on. Phone instantly jumps 30% or so. But generally i tend to power on without the charger attached so as not to stuff up the battery stats.
Sent from my GT-I9000 using XDA App

Anyway this behavior is not correct.
Samsung changed recently battery drivers in JPX sources and the problem is still persistent. I suspect it might be related to wrong battery voltage measuring point (hardware design flaw? although most problems with sgs are/were software related) or result misinterpretation.
Or their Q/A team is so clueless that they didnt notice that.

hardcore said:
EDIT: I notice this difference in battery meter reading tends to happen only with the *real* charger, and not when connect to a USB port on a PC.
Click to expand...
Click to collapse
I just tested this. 5% battery. Reboot with usb plugged in. 50%battery. The battery also seems to drain really fast after the reboot.
I am plugged in using original usb cable in a usb on the front panel of my pc...
Edit: im still plugged in and it's going down... i boot with usb at 50% leave it in and while charging the battery goes down... i left it in and now it's going 49...48...47 while charging... wtf lol
Sent from my GT-I9000 using XDA App

Lightarrow said:
I just tested this. 5% battery. Reboot with usb plugged in. 50%battery. The battery also seems to drain really fast after the reboot.
I am plugged in using original usb cable in a usb on the front panel of my pc...
Edit: im still plugged in and it's going down... i boot with usb at 50% leave it in and while charging the battery goes down... i left it in and now it's going 49...48...47 while charging... wtf lol
Sent from my GT-I9000 using XDA App
Click to expand...
Click to collapse
My guess is this is because the actual level of the battery is 5%, and 'cause it's plugged in it's saying 50% for some strange reason. So really you're charging from 5% up to 50% (and eventually more, but that aside), and I think the phone is averaging between your actual battery level and the 50% every time you go up 1%? Just my guess.

johanaikema said:
My guess is this is because the actual level of the battery is 5%, and cause it's plugged in it's saying 50% for some strange reason. So really you're charging from 5% up to 50% (and eventually more, but that aside), and I think the phone is averaging between you're actual battery level and the 50% every time you go up 1%? Just my guess.
Click to expand...
Click to collapse
Yeay that is what im thinking too weird stuff.
@hardcore : just tried your suggestion. I shut down with the cable plugged in. Remove it. Reboot. But my battery is still at 47... ill try to go into cwm to see if that triggers something. Or maybe remove the battery and insert it again...
Sent from my GT-I9000 using XDA App

Ok. I tried this : removed my battery, waited 5 seconds, reput my battery, reboot all with charger unplugged. Battery went from 47 to 52. So this had no effect.
Then i shut down the phone, used 3br to get into recovery (cwm) did nothing except select reboot phone now and the phone rebooted, now 12% battery.
Btw using all tweaks in your kernel except tun.
Weird stuff...
Sent from my GT-I9000 using XDA App

noticed this months back too but didnt think much about it.
i just figured the software is reading the higher voltage during charge and reporting it wrong during boot.
*could be wrong
EDIT: and the diff is quite big, increase of 20-30%

hardcore said:
What I'm suggesting is a bit different.
Power off phone.
Power on phone again, without plugging anything in.
After phone has booted, plug in charger.
EDIT: I notice this difference in battery meter reading tends to happen only with the *real* charger, and not when connect to a USB port on a PC.
Click to expand...
Click to collapse
what @weirder post is the true fact about the lithium ion charge process. your charging method is called bump charging. but that way of charging the juice wear off the battery life sooner than normal charging..

I've been checking out the battery meter source code, and I think the battery level is calculated *only* from the battery voltage. Which is quite inaccurate, compared to laptop batteries which keep track of the charge, etc.

hardcore said:
I've been checking out the battery meter source code, and I think the battery level is calculated *only* from the battery voltage. Which is quite inaccurate, compared to laptop batteries which keep track of the charge, etc.
Click to expand...
Click to collapse
This could be improved by using its temperature. Since the SoC is a function of temperature, charge history, and current evolution over the time.
[[]]

I tried the bump charging till the meter says 100% and right after unplugging from the charger the meter reads 98%. I let the battery drain up to 96% and connected my phone into a usb port of my PC and when the meter say its 100% charged, i disconnected the phone from the usb port and wallah...it stays at 100% charged and it has been at 100% even after 15 minutes...

I really don't recommend bump charging. You risk damaging your battery by overcharging. Or worse, making it blow up due to overcharging! I know it sounds paranoid but you never know...

Phone charging really slow??

So my s2 has been charging really slow, like today it took like 5 hours to fully charge, and when connected to charger if I'm using it it wont charge very well, like the battery will stay at lets say 20% when im using it and charging it, it might even go down more. it used to charge pretty well even if I was on it. Cuz this be the charger, or is my battery messed up?? Im using the charger that came with the phone.
Sent from Flip's SGS2

Are you charging through a usb port on your computer or ac? If it is with usb port then yes it will charge at a much slower rate. Also if you have a lot of apps running or backround data going it will also cause your charging to slow down some. I would say through usb without any apps open and backround data stopped It would take a few hours to charge say from 20%. Through AC in the same condition probly 1.5 hours. Try to reboot your phone and then plug it in to charge to see if that doesnt speed it up any. If it does then you know you have backround data moving at a fast rate and that would be your reason to slow the charge down.

Yeah I'm charging with the wall charger, not thru usb
Sent from Flip's SGS2

thats pretty weird...have you tried using another usb cable?? maybe the cable is faulty?

Calibrating the battery
elflip88 said:
So my s2 has been charging really slow, like today it took like 5 hours to fully charge, and when connected to charger if I'm using it it wont charge very well, like the battery will stay at lets say 20% when im using it and charging it, it might even go down more. it used to charge pretty well even if I was on it. Cuz this be the charger, or is my battery messed up?? Im using the charger that came with the phone.
Sent from Flip's SGS2
Click to expand...
Click to collapse
You could try calibrating the battery, maybe. To do that, turn the phone off. Charge to full (make sure it's full, by taking it off of the charger and putting it back on...the indicator should read 100% almost immediately when reattached to power).
When the battery is full, with the phone still turned off, remove the battery for about 2 minutes. After 2 minutes, reinsert battery and restart phone.
Battery will be calibrated. This may not resolve the problem of a slow charge, but will clear 'battery memory' which may have been preventing it from charging completely (and, I suspect, may have inhibited charging).
Good luck!

I was using an aftermarket wall charger and had similar results. Switched to the USB/AC converter that came with the phone and all was well.

sean is here. said:
You could try calibrating the battery, maybe. To do that, turn the phone off. Charge to full (make sure it's full, by taking it off of the charger and putting it back on...the indicator should read 100% almost immediately when reattached to power).
When the battery is full, with the phone still turned off, remove the battery for about 2 minutes. After 2 minutes, reinsert battery and restart phone.
Battery will be calibrated. This may not resolve the problem of a slow charge, but will clear 'battery memory' which may have been preventing it from charging completely (and, I suspect, may have inhibited charging).
Good luck!
Click to expand...
Click to collapse
Yes, try Battery Calibration from the market. Only works on rooted devices, and follow instructions.

Battery Calibration
abctilly said:
Yes, try Battery Calibration from the market. Only works on rooted devices, and follow instructions.
Click to expand...
Click to collapse
Actually, one doesn't need an app to calibrate the battery. If you follow the instructions above, the app is unnecessary. And the phone mustn't be rooted

YODA? ^^^^

Hey elflip88, have you found the issue yet?
I have the same problem on my HTC Amaze 4G. It's charging 1% every 3 minutes (adds up to 5 hours)
I'm also using the wall charger...oh damn, I'm starting to think I have a faulty device / battery...
yelp!

For the record Samsung devices are known to be slow at charging so with that considered.... You still shouldn't be at 5 hrs. I would find a battery stats app charge your battery over night and check the chart to see exactly how long it takes to go from 0 - 100. Make sure your batter status is good. Also check the voltage coming into your phone from your charger. There are plenty of battery stat apps in the market that will do this sort of thing. Of course make sure your battery doesn't have water damage of course too lol.
Sent from my SGH-T989 using XDA App

I've had the same problem with mine. But, I can get 1.5 days without charging and moderate usage. Charge it up, drain it, charge it back up then wipe your battery stats in recovery.

This may help if you're using an aftermarket wall charger
If you guys are having issues with slow charging using an aftermarket wall charger, it could be that the phone is charging in a USB state rather than an AC charging state. QuickCharge could alleviate your issues. The cable is inserted between the wall charger and the USB cable that goes to your phone. You can find the product on Amazon. It's the 2nd of 3rd item from the top when you search 'QuickCharge'.

I find that when I fully drain my battery and charge it, it's really slow. Once the phone has enough battery to stay on, I unplugged it and replugged it and it charges normal again.

elflip88 said:
So my s2 has been charging really slow, like today it took like 5 hours to fully charge, and when connected to charger if I'm using it it wont charge very well, like the battery will stay at lets say 20% when im using it and charging it, it might even go down more. it used to charge pretty well even if I was on it. Cuz this be the charger, or is my battery messed up?? Im using the charger that came with the phone.
Sent from Flip's SGS2
Click to expand...
Click to collapse
It's your wifi and your apps using wifi. Turn wifi off while charging. I used to charge 4 hours + on my S2. Reduced to 2 and some change when I turn off wifi.
Also, I struggle to make it through a working day with wifi on. Turn wifi off and I can do 4 days no problem.

audscott said:
I was using an aftermarket wall charger and had similar results. Switched to the USB/AC converter that came with the phone and all was well.
Click to expand...
Click to collapse
I've had the same problems using an aftermarket wall charger.

I old suggest using a different outlet if you haven't done that yet.
Sent from my SGH-T989 using xda

What? Wifi (while connected) users significantly less power than 3g or HSPA+ (4G) data..
Sent from my SAMSUNG-SGH-I727 using XDA

i had that issue once, it had to do with my ROM i imagne... i flashed a new one and i havent had a problem ever since.

i m using this wall charge and use this battery... it is working fine and no problem at all
http://www.ebay.com/itm/Anker-Battery-for-Samsung-Galaxy-S-II-from-T-mobile-
http://www.cellphoneshop.net/hdw179...ccessories&hash=item4ab527cf3b#ht_2001wt_1396

[Q] Phone loses battery % WHILE CHARGING? How is this even possible?

How is my phone losing battery while charging ? It's insanely hot too.
CM10 stable - Jelly Bean - SGS3 - Bell
NOTHING is running. I have been closing all apps.

Did you try rebooting it?

Tony_YYZ said:
Did you try rebooting it?
Click to expand...
Click to collapse
yes

Have you tried another cord, I had an issue like this and a new cord fixed it. Also are you charging through a computer or wall socket or both?

nsmith4 said:
Have you tried another cord, I had an issue like this and a new cord fixed it. Also are you charging through a computer or wall socket or both?
Click to expand...
Click to collapse
USB to PC

I would try another cord and/or a different pc if possible.
Also check the battery stats to see if a certain app takes up a lot of battery (it may restart the app as soon as you kill it).
If none of that works I would wipe and re-install the rom or another rom for testing purposes.
And if it occurs on multiple roms/kernals it maybe hardware/battery related.

i believe you shouldn't charge it with a PC usually. i could be wrong though.

Funkadelick said:
yes
Click to expand...
Click to collapse
Try using a wall charger
slicetwo said:
i believe you shouldn't charge it with a PC usually. i could be wrong though.
Click to expand...
Click to collapse
Nothing wrong with charging via a PC. It'll just charge a lot slower.

Tony_YYZ said:
Nothing wrong with charging via a PC. It'll just charge a lot slower.
Click to expand...
Click to collapse
Not necessarily - in my experience it depends on how much power your computer's USB ports are capable of providing, and even that can vary depending on what controller is powering what ports and the like. I normally charge my phone from my computer and it takes roughly the same time as using the wall charger, though I've noticed that it doesn't seem to charge as quickly on at least one or two other computers I've had the phone plugged into.

USB usually has 500mA, where as the charger supplied by Samsung has 1000mA. It -will- charge faster with the supplied charger.

Ecip said:
USB usually has 500mA, where as the charger supplied by Samsung has 1000mA. It -will- charge faster with the supplied charger.
Click to expand...
Click to collapse
That is still sufficient power to run the phone without the battery. So at worse, the battery stays at the same percentage. It's not normal for the battery to drop while the phone is plugged in.
Sent from my SGH-I747M using xda app-developers app

smelenchuk said:
Not necessarily - in my experience it depends on how much power your computer's USB ports are capable of providing, and even that can vary depending on what controller is powering what ports and the like. I normally charge my phone from my computer and it takes roughly the same time as using the wall charger, though I've noticed that it doesn't seem to charge as quickly on at least one or two other computers I've had the phone plugged into.
Click to expand...
Click to collapse
Higher powered USB ports are far and few inbetween. Usually higher end PC's/controllers will accommodate this. Most PC's though only push about 500mA via the USB ports.

Funkadelick said:
How is my phone losing battery while charging ? It's insanely hot too.
CM10 stable - Jelly Bean - SGS3 - Bell
NOTHING is running. I have been closing all apps.
Click to expand...
Click to collapse
once in while my phone will bug out like that, even if you turn it on and off. only way to really fix it is a battery pull.

I have found that if I am doing anything on it (screen on, gaming, Internet, etc.) and connected to my laptop, it often will not have enough power on the subject to compensate for what I am using and will only slow the speed the battery decreases.

That's crazy. Try a factory install. Another possible point of contention, lock frequencies and stop all overclocking. On custom Roms is your clock/governor settings set in the rom OR an app? If you have both set to boot they could be conflicting and constantly switching clock speed and governor settings.
Another thing to do. Charge to 100%. Go into recovery and delete your battery stats

yeah.. that's happened with me while pc usb charging. i was running maps, playing music, and texting at the same time with the screen constantly on. at first it was a slow drain.. then if i turn the screen off it would charge.. just too many things at once. but governor, voltages, schedulers do play a factor.

I don't think you guys realize. I don't have a single app running. At lunch time today I basically had 95% charge on my phone -- and it was connected to my computer.
In about 5 hours the ONLY thing I did was send a few txts. Sent maybe 20 txts in 5 hours. The ENTIRE time my phone was plugged in.
My phone is now at 84% and it's super hot. Opening battery to see what's up? doesn't show anything using any battery juice.
This phone fuking sucks.

Funkadelick said:
I don't think you guys realize. I don't have a single app running. At lunch time today I basically had 95% charge on my phone -- and it was connected to my computer.
In about 5 hours the ONLY thing I did was send a few txts. Sent maybe 20 txts in 5 hours. The ENTIRE time my phone was plugged in.
My phone is now at 84% and it's super hot. Opening battery to see what's up? doesn't show anything using any battery juice.
This phone fuking sucks.
Click to expand...
Click to collapse
This only happens while charging via PC?
What is it that's getting hot, the very bottom of the phone or the battery?
Have you tried going to retail store with this problem and see if they swap out the battery for you? Might just be a faulty battery.
Have you tried different PC's and/or different usb cables?
Sent from my SGH-I747 using xda premium

Faulty cable
Funkadelick said:
How is my phone losing battery while charging ? It's insanely hot too.
CM10 stable - Jelly Bean - SGS3 - Bell
NOTHING is running. I have been closing all apps.
Click to expand...
Click to collapse
I just had the same problem with my brand new stock Galaxy S4.
I bought the new 2amp Genuine Samsung car charger and on the 1st use with my phone turned off it took 3 hours to charge 49 % battery and when i turned the phone on it would say it was charging but the battery was going down.
Faulty cable. Used the car charger with cable provided with phone, all fine. But the Galaxy S4 with auto brightness even with the genuine wall charger if you are playing games it takes ages ti charge and sometimes won't even charge and loose battery.
Just use the genuine charger and try not to use the phone while charging.

[Q] Battery charges when tablet is turned on

Hi,
how described at the link support.google.com/nexus/answer/3257354?hl=en&ref_topic=3415471 the nexus 7 should not charge when is turned on and plugged to a computer but mine does.
I think it is strange it charges when I plug to usb computer but I need to plug because I use it to test apps during development.
Is it the normal behavior to charge also when turned on?
Initally I posted (wrongly) on first gen nexus 7 forum, so apologize me if you saw this post in the other forum

dafiduck said:
Hi,
how described at the link support.google.com/nexus/answer/3257354?hl=en&ref_topic=3415471 the nexus 7 should not charge when is turned on and plugged to a computer but mine does.
I think it is strange it charges when I plug to usb computer but I need to plug because I use it to test apps during development.
Is it the normal behavior to charge also when turned on?
Initally I posted (wrongly) on first gen nexus 7 forum, so apologize me if you saw this post in the other forum
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Click to collapse
The page is technically correct, if a bit misleading. It will show the charging icon and draw power with it plugged into a USB port, but it's still going to run down the battery faster than it can recharge if the screen is on, IIRC.

That the N7 charges with the screen on is normal. But it's limited to 2.5W power draw from the USB port. Depending on CPU load / display brightness, you will easily exceed that.
They probably thought it would be less confusing for users to state it doesn't charge, when in fact it really depends on the power consumption.

I must leqve the display on because I test my applications on it, so now I don't understand if I can damage the nexus using it as a dev terminal

dafiduck said:
I must leqve the display on because I test my applications on it, so now I don't understand if I can damage the nexus using it as a dev terminal
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You won't. The charger will stop charging when the battery is full. Of course, the battery will degrade faster, if it's constantly kept at full charge.
But there is this (Battery life extender):
http://forum.xda-developers.com/showthread.php?t=2469261
It's included in the ElementalX kernel:
http://forum.xda-developers.com/showpost.php?p=46479549&postcount=1189

tni.andro said:
You won't. The charger will stop charging when the battery is full. Of course, the battery will degrade faster, if it's constantly kept at full charge.
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After a test dev session, generally runs for 15 minutes, I unplug the device and I use it normally until battery is low or under 1% so I hope this "good citizen" behavior can help battery life.
tni.andro said:
But there is this (Battery life extender):
http://forum.xda-developers.com/showthread.php?t=2469261
It's included in the ElementalX kernel:
http://forum.xda-developers.com/showpost.php?p=46479549&postcount=1189
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Good to know about these tweaks , thanks