Develop Bugs

Highest Charging Current for One X

Hi all:
I just did a test on the maximum charging current of the One X using current measurement equipment, and it shows that the One X does not draw above 460mA of current while charging.
With this value, i suspect that the One X limits max charging current at 500mA, which means 3 things:
1) Using any previous generation USB charger (750mA or 850mA or 1A) is good enough. Attempting to use the iPad's charger (rated at 2A) WILL NOT get you faster charging time.
2) When using battery draining applications, the charging current may not be enough for you to both CHARGE and USE the Phone. Thus it might be a better idea to give your One X some dedicated charging time.
3) Some computer USB ports may specify 500mA of output current, but there are many times the available current is less than that. On my USB port, the charging current is only about 300mA at times. So it is better to use a dedicated charger if you have it available. Having that said, however, it is still ok to charge the One X with a USB port at 300mA, just that charging will take longer.
That's all I have to report. Useful information for all.

limestone said:
Useful information for all.
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Click to collapse
Useful indeed. Thanks
Sent from my HTC Vivid using XDA app

I've had mine charge at 780mAh+ before. 1amp HTC charger. Charge rate slows down at the last 20-30% or so. So from 70%-100% battery, charge rates normally slow to about 450mAh.

limestone said:
Hi all:
1) Using any previous generation USB charger (750mA or 850mA or 1A) is good enough. Attempting to use the iPad's charger (rated at 2A) WILL NOT get you faster charging time.
Useful information for all.
Click to expand...
Click to collapse
thanks a lot, i can confirm the statement above because my stock charger is broken and i'm using the ipad's one.
bye

i tried to use the charger for htc chacha and hd2..
both does not work.. red light will light up but after a while it will go off and the phone does not charge..

Charging my HOX while the phones working hard eventually (after say, 5 mins), causes the charge LED to flash green/red. I've had this twice now, once while playing a 720P HD film, and once when playing Glowball.
Both times the phone was very hot, so i'm not sure if the LED thing was to indicate that the battery was too hot to charge, or that the charger could not supply enough power to charge and power the phone at the same time.

fi3ry_icy said:
i tried to use the charger for htc chacha and hd2..
both does not work.. red light will light up but after a while it will go off and the phone does not charge..
Click to expand...
Click to collapse
I'm using my HD2 charger at work every day. It charges at about 400/500mA.
Original charger gives me 650/750mA (lowers at the end)

chaps said:
Charging my HOX while the phones working hard eventually (after say, 5 mins), causes the charge LED to flash green/red. I've had this twice now, once while playing a 720P HD film, and once when playing Glowball.
Both times the phone was very hot, so i'm not sure if the LED thing was to indicate that the battery was too hot to charge, or that the charger could not supply enough power to charge and power the phone at the same time.
Click to expand...
Click to collapse
If the charger cannot cope with the discharge from the game, a pop up message actually appears. If it's blinking means it's too hot. Try not to do anything intensive the last 20-30% remaining (meaning at 70-100% battery).

Nice info thanks
Sent from my HTC One X using XDA

fi3ry_icy said:
i tried to use the charger for htc chacha and hd2..
both does not work.. red light will light up but after a while it will go off and the phone does not charge..
Click to expand...
Click to collapse
Same here... I am using the Atrix 4G (US) charger, it does not charge the phone. The charger gives output of 850mA. It does charge when plugged into the laptop, but I think it will take very long that way.
*edit for posterity*
after a while (I did it when battery had charged to 20%), I could connect the Moto US charger, and it would show as "AC". It would not want to charge through it when the battery was really low (2%), but it would charge via USB in that case. Weird behavior, IMO.

USB limited to 500. AC limited to 1A.
Sent from my HTC One X using xda premium

If you want maximum speed of charging (AC charging) you need:
1A charger with shorted D+ and D- pins (eg, original HTC charger).
iPad charger probably doesn't have these pins shorted, so in this case phone will see it as USB charging (you can check it in settings->battery) and will limit charging current to 500mA. Also lot of aftermarket car chargers will work only in USB mode despite they are able to supply 1A.
Here you can find some info on USB Charging Ports (shorted D+- pins):
http://en.wikipedia.org/wiki/Universal_Serial_Bus#Charging_ports_and_accessory_charging_adapters

When charger is "USB", it will not draw more than 500mA from the charger, and usually it will not charge at all (because the current draw with screen on is higher than 500mA).
When charger is AC, it seems to draw 1000mA - but this is still too low to charge while phone is doing anything, as it will draw 700mA and charge ~250mA top.
I hope this can be tuned in kernel, because it sucks, I also hope that power source can be AC (and not battery - look in dmesg when charger is connected), because battery gets too hot when under load...

colin_ktp said:
If you want maximum speed of charging (AC charging) you need:
1A charger with shorted D+ and D- pins (eg, original HTC charger).
iPad charger probably doesn't have these pins shorted, so in this case phone will see it as USB charging (you can check it in settings->battery) and will limit charging current to 500mA. Also lot of aftermarket car chargers will work only in USB mode despite they are able to supply 1A.
Here you can find some info on USB Charging Ports (shorted D+- pins):
http://en.wikipedia.org/wiki/Universal_Serial_Bus#Charging_ports_and_accessory_charging_adapters
Click to expand...
Click to collapse
Can you post a potential list of car charger which are working at 1mA according to you?

I've only tested few devices:
Extrememac external battery for iPhone/iPad (max 2A) had pins not shorted - USB charging mode on One X (500mA).
Some cheap car adapters - max 1A (according to spec) - USB charging mode on One X.
To fox this problem you should prepare a USB extension cable or micro-usb cable with shorted D+ and D- pins and it should be recognized as AC adapter. I think that also some old HTC phone chargers might come with shorted pins in cable already, but don't know which...

What about the official HTC car charger?

MickyMax said:
What about the official HTC car charger?
Click to expand...
Click to collapse
Yes, that one will charge at the full rate.
There is no list of known good chargers - it's down to luck or a recommendation from someone who found one. You can be sure that any charger advertised as "iPhone, iPad or iPod" compatible will NOT charge your One X at the full rate.
I found one recently in a local petrol station shop. It was £5. I took it apart to have a look and the D+ and D- pins are correctly connected together (via a low value resistor) so it charges at the full rate.
So, I might suggest you look for the cheapest Chinese car charger you can.

USB charging not OK inside a car
zvieratko said:
When charger is "USB", it will not draw more than 500mA from the charger, and usually it will not charge at all (because the current draw with screen on is higher than 500mA).
When charger is AC, it seems to draw 1000mA - but this is still too low to charge while phone is doing anything, as it will draw 700mA and charge ~250mA top.
I hope this can be tuned in kernel, because it sucks, I also hope that power source can be AC (and not battery - look in dmesg when charger is connected), because battery gets too hot when under load...
Click to expand...
Click to collapse
Bingo. I also noticed that when I have the screen on at 100% brightness, GPS and Bluetooth on, i.e. in the car, the USB charger cannot even keep up with the battery drain.
On top of that, the battery gets really hot.
I did not have any of these issues with my SGS2, and frankly, I think it's very disappointing. One should at least be able to stay on the same battery level while doing nothing too fancy and on USB inside a car.

A380 said:
Bingo. I also noticed that when I have the screen on at 100% brightness, GPS and Bluetooth on, i.e. in the car, the USB charger cannot even keep up with the battery drain.
On top of that, the battery gets really hot.
I did not have any of these issues with my SGS2, and frankly, I think it's very disappointing. One should at least be able to stay on the same battery level while doing nothing too fancy and on USB inside a car.
Click to expand...
Click to collapse
There are a lot of factors in the charging current. When you charge, the battery will heat up during the process, especially towards the end of the charging cycle. If you are using your phone at the same time and cause even more heat and charging may slow down to prevent overheating. Also, as mentioned prior, charging slows down as capacity is reached. 100% brightness, GPS, and Bluetooth all on has always walked the fine line of just barely keeping up on my past phones on a 500 mA USB charger. On top of that, this phone is a lot more powerful than an SGS2 and the T3 and big screen produce more heat which may be slowing your charging more.
The problem is a lot of cheap chargers that the phone thinks are USB chargers, not AC chargers, thus causing them to only charge at 500 mA. If you have a proper charger, or a properly modified charger, you should get more like 1A, assuming conditions are right.
In the past I've used Battery Monitor Widget from the Play store to show my charging current on a widget, as well as track and graph battery use, charging current, temperature, etc. Might want to give it a try if you're more interested in charging details.

Im using my htc desire charger and cable (the one that splits in two). It works fine for me but it does take a while to get a full charge. Should i use the charger and cable that came with the phone?

6 Volt Charger

Recently bought a camping lantern that runs on a built in 6v 4.5 AH lead acid battery. It also has a USB connector which is for charging cell phones. I initially thought that the USB would be giving off a safe 5v but on testing it turns out that it is 6 volts straight from the battery.
Is this safe to use occasionally while camping? Will that extra 1 volt kill the battery or is there some mechanism inside the phone to regulate that voltage to a safe level?

Good question....hope someone has the answer for you.
Sent from my SCH-I535 using xda app-developers app

executionist said:
Recently bought a camping lantern that runs on a built in 6v 4.5 AH lead acid battery. It also has a USB connector which is for charging cell phones. I initially thought that the USB would be giving off a safe 5v but on testing it turns out that it is 6 volts straight from the battery.
Is this safe to use occasionally while camping? Will that extra 1 volt kill the battery or is there some mechanism inside the phone to regulate that voltage to a safe level?
Click to expand...
Click to collapse
Of course there should be.You get more than 6v in a power socket around the house.

Gkikas said:
Of course there should be.You get more than 6v in a power socket around the house.
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Click to collapse
No one plugs their phone directly to the wall socket :/ Thats what the charger is for, it only gives 5v to the phone. Just need to know if it can regulate that 6v to a safe level.
*edit. I think no one here would know about the hardware aspects of a phone. Can someone point me to a forum or anywhere where they may know the answer to a question like this?

May I asked how you measured this?
I'd love to check what output my 12v chargers are outputting

TieNN89 said:
May I asked how you measured this?
I'd love to check what output my 12v chargers are outputting
Click to expand...
Click to collapse
A multimeter and a stripped usb cable

executionist said:
A multimeter and a stripped usb cable
Click to expand...
Click to collapse
ah yeah
My brain has already flicked off for the day LOL

if you use IRC, try the freenode server in the ##electronics channel. they should help you out there. pretty nice ppl in general there.
Sent from my GT-I9300 using xda app-developers app

?
I'm interested as well. Will 6 volts @ 500mAh fry the phone?

Ok, I am an electronic engineer so a few comments.
I have no idea what kind of charging circuit is in our phones, could probably look it up but ..... in my opinion only 10% above 5V is to be considered safe.
Now you are talking about a 6V battery. That battery is not always 6V. A nice example is the 12V battery in your car which is 12.8V when fully charged. Another example are the cells inside our phones which have a nominal Voltage of 3.7V but are charged to 4.2V.
The Voltage they put on those things is the nominal Voltage.
I would check if there is no electronic circuit in that lamp since I would not connect anything directly to a battery at all.
If you go camping I would check this thing coolook pb-2000. Insert 4 x 18650 batts and you can do a couple of recharges. Very good box for the price and you can salvage 18650 from broken laptop batt packs ... but google and youtube a bit before you do that to make sure you do it the right way.

I'm also interested, any news?

You can see the specs of this type of batteries here. The 6V is nominal, as already mentioned above. The maximum noted is 6.9V and TBH, i would be rather reluctant to test is my SGS3 charging circuit likes the idea of being fed with 40% higher voltage than usual.
Are you sure there is nothing in the lantern that would limit the voltage under load? Could be something as simple as 2 diodes in series, in this case measuring the voltage on the open circuit, totally unloaded, with a DMM that barely draws microamps from it, would show the battery voltage. Try drawing some current from it (use a resistor, a USB LED lamp, etc) while measuring. I seriously doubt a self-respecting vendor would setup a USB port on that thing that would potentially output 40% more than specs, really.
PS: if the port is, indeed, fed straight from that battery, i would rather avoid hooking my SGS3 to it. Even though, it would probably survive.
---------- Post added at 07:08 PM ---------- Previous post was at 06:59 PM ----------
lukesan said:
I have no idea what kind of charging circuit is in our phones...
Click to expand...
Click to collapse
MAX77686. Good luck finding the datasheet. And good luck trying to guess if there is anything else potentially fed straight from the USB connector. The bottom line is - i wouldn't dare

Solder this to red wire https://en.wikipedia.org/wiki/Zener_diode
OFC you need 5V model

GR0S said:
Solder this to red wire https://en.wikipedia.org/wiki/Zener_diode
OFC you need 5V model
Click to expand...
Click to collapse
Not if it doesn't have a resistor in series. And wait. if the battery is at 6.8 Volt and you have a 5.1 Volt zener and it is charging at 1 Amp so you will need a power resistor. You will have a lot of loss of energy because it will go away in heat.
You could use a dc-dc convertor but believe me forget about it and get one of those charging banks where you can put in your own cells.

lukesan said:
Not if it doesn't have a resistor in series. And wait. if the battery is at 6.8 Volt and you have a 5.1 Volt zener and it is charging at 1 Amp so you will need a power resistor. You will have a lot of loss of energy because it will go away in heat.
You could use a dc-dc convertor but believe me forget about it and get one of those charging banks where you can put in your own cells.
Click to expand...
Click to collapse
I'm not sure about how practical it would be to be cutting usb cables and wiring zener diodes just to use this lamp....
I think I had a charger that supplied too much voltage (I'm not positive I didn't measure the voltage output or anything), but I can say that the phone did not like it. It would eventually charge somewhat, but the touch screen wouldn't work and would go bezerk if touched lol.
Again I'm not sure how much V it supplied, but I would assume it was more than 6V. It didn't really damage the phones either, I would try it.

Here's your answer, definitively:
6v at the source (the lantern in this case) will probably be 5v or less at the phone because of the resistance in the USB cable itself. The longer the cable is the higher the resistance will be and thus the more voltage you lose to it. Also, the cheaper the cable (the thinner the wires) the more voltage you will lose per foot.
Here's some specs you can plug into THIS VOLTAGE CALCULATOR:
The USB definition specifies up to 5.3v.
Most USB cables will use 30awg wire or maybe 28awg for the better ones.
Depending on which of the sources I've read, some USB cables/chargers use one pair of wires for charging, and some will use two pairs. You can see that using two pairs of conductors drastically improves the voltage transmission but even still, at 28awg over a 6foot cable you're still losing .75v which puts you at 5.25v and well within the USB spec.
So the lantern is fine to use with your phone with your average 6-foot USB cord.
If you're like me and prefer 10-15 foot USB cords in some places you would actually benefit from a 6v or even 7v power supply at the wall. I've found that even on the OEM Samsung wall charger, when I use a 10-foot cable I don't get enough juice to actually charge my S4. With the screen on the battery charge level still drops. The Galaxy Charge Rate app shows something like 500ma charge rate and that's because there's not enough voltage / too much voltage-drop across the long cable. (Radio Shack sells a modular, adjustable voltage wall-wart power supply as well as USB and micro-USB adapters for it. I'm starting to experiment with it and the long cables.)

USB voltage vs charging current
This is an old thread, but I can confirm that my moto G charges at 6v. Apparently the original Motorola charger outputs 5.75v. I hooked up a variable power supply to my phone. The data lines are shorted together to indicate a high current power source is present. The moto G will test load the power supply before settling on a stable charging current. One that does not cause the voltage to sag excessively. When I applied 5v the charging current was approximately 600 mA. At 6v the charging current was approx 1200 mA. The charging current was measured directly on the phone using an app called ampere.
So I conclude that Motorola use this tactic to ensure their phones charge fastest with their chargers. On the up side, its fun watching my phone go from 40% to 100% in 45 minutes

USB charging cable

Lately I've noticed something odd. Depending on the USB cable I use the charge rate seems to vary substantially. In fact, in some cases under heavy phone usage, I've seen the battery decrease while on the charger. Now, I know what you're thinking: Some USB cables have the D+/D- pins shorted which switches from USB (500mA) to AC (1A) charging mode. I'm using a really cool CTC-2USB-5V2A charger which seems to show up as AC on all cables (including the ones that barely charge it). The two cables I know are charging it well are the one that came with my HP Touchpad and the one that came with my Kindle Fire HD 7, the ones that didn't have been el-cheapo eBay cables. Since its showing up as AC for all the cables, I'm assuming the only difference can be that the eBay cables use thinner wires which take more voltage drop.
Have people seen this before? Is this the problem? Does anyone know where to get some quality 2 meter / 6 ft cables cheap?

If you want to verify that one cable is allowing more current through than another, I would suggest getting "Battery Monitor Widget" by 3c (in the play store)
Put the apps widget on your screen, plug our phone in and wait for widget to update. Do the same for each cable and compare

CNexus, I am absolutely convinced one is charging faster than another.I was using the battery monitoring that came with the phone (or at least the one in Blazer ROM). You can plug one cable in and update the graph and the slope of the battery state is much higher on one cable than another. I installed battery monitor widget and I do not see anything that shows how much current is going into the phone.
But this really doesn't address the question of why one cable is charging faster than another, is it the wire gauge? Is there something else going on I don't know about?

hpmaxim said:
CNexus, I am absolutely convinced one is charging faster than another.I was using the battery monitoring that came with the phone (or at least the one in Blazer ROM). You can plug one cable in and update the graph and the slope of the battery state is much higher on one cable than another. I installed battery monitor widget and I do not see anything that shows how much current is going into the phone.
But this really doesn't address the question of why one cable is charging faster than another, is it the wire gauge? Is there something else going on I don't know about?
Click to expand...
Click to collapse
I can absolutely verify that this is true. It's usually that the pins in the micro sd port are running thin from normal use. Usually normal wear and tear, or possibly the cable has gotten crimped somewhere on it Respectively, the same Non- charging cables are likely to corrupt data transfer as well, making it difficult to do development, or transfer your favorite videos or songs.. Someone recently stole my new cable and all the files I'd transferred to my phone from the computer or vice versa from my older cable were corrupted. Especially ROMS, KERneLS, and Video. This could be a potential huge problem for someone in a sticky situation needing to ODIN, or make an ABD shell connection. I suggest tossing those cables and buying new ones. I know they're expensive, but it might be the difference between having your phone soft bricked till next payday or not.

Timmetal, just to be clear I am comparing multiple identical eBay cables to the Touchpad/Kindle Fire cables.... Sounds like you are saying it is a manufacturing defect in the cables (presumably all of them) that are not necessarily related to the wire gauge. Regardles...
A 6 foot 28 gauge cable would drop about 800+ mV (which is a lot, since a fully charged battery is probably around 4.2V and USB is 5V).
A 6 foot 24 gauge cable would be about 400 mV drop.
A 6 foot 22 gauge cable would probably be 250-300 mV drop.
Monoprice has 3 styles of cable:
1) the 28/28 economy cable (which I presume means 28 gauge on all wires) for 81 cents the
2) the 24/28 cable (presumably 24 gauge on power and ground, and 28 on the others) for $1.40
3) the "premium" cable which they don't give any info on, for $2.96
Newegg has a 22 gauge for $4
Price isn't that big of a deal one 1, but I'll probably buy 10 which starts to make a difference (although prices go down a bit with quantity on all of these). Sounds like the 24/28 Monoprice might be the best bet.

Battery monitor widget is an app, after you download it long press on your home screen > widgets > and there should be one for the "battery monitor widget" app, so basically put the "battery monitor widget" widget on one of your homescreens
And im not saying this is to see whether one is charging more than another, because you can just see that clearly
This is to see how much more it is because this app shows you the mA coming through the cord

The phone software controls the charge rate based on what it thinks it is plugged into. I think it limits its draw to 500ma if it senses a USB port on the other end (since the USB standard limits it to 500ma anyway), it charges at 700ma if it senses a wall-wart type charger. Not sure how it senses the difference, but you will notice on the lock screen it will say either Charging (USB) or Charging (AC).

Questions and help issues go in Q&A
Thread moved
FNM

poit said:
The phone software controls the charge rate based on what it thinks it is plugged into. I think it limits its draw to 500ma if it senses a USB port on the other end (since the USB standard limits it to 500ma anyway), it charges at 700ma if it senses a wall-wart type charger. Not sure how it senses the difference, but you will notice on the lock screen it will say either Charging (USB) or Charging (AC).
Click to expand...
Click to collapse
Sorry if I didn't make this clear, the phone is claiming it is an AC charger in both cases, but one cable versus another makes a big difference in charging speed. Anyway, I ordered 9 of the $1.40 Monoprice cables. We'll see if they work.

poit said:
The phone software controls the charge rate based on what it thinks it is plugged into. I think it limits its draw to 500ma if it senses a USB port on the other end (since the USB standard limits it to 500ma anyway), it charges at 700ma if it senses a wall-wart type charger. Not sure how it senses the difference, but you will notice on the lock screen it will say either Charging (USB) or Charging (AC).
Click to expand...
Click to collapse
Sort of off topic but Interesting. My lock screen just shows charging. USB port on computer, USB cable plugged into wall charger or dedicated 700mah Blackberry wall charger, it makes no distinction as to how it's being charged. It does charge faster using a wall charger obviously but I've never noticed a difference in rate between using different cables.

Can anyone help me out with Tab Pro 8.4 Battery problem?

Ok, well...
I'm Korean, and I've searched almost every Korean tablet forums, yet can't find the reason :crying:
So I came to here, XDA.
The problem is, my Tab Pro 8.4 won't charge at all.
It's looks like an usual charging problem of Tab Pro 8.4, however, mine's little bit different.
With the charger plugged in and tablet is on, I can see the lighting shape on the battery icon at the status bar (which appears the charger is plugged in) ,
but no matter how long I charge the tablet, it's 0% and turn off after like...10 secs.
With the charger plugged in and tablet is off, I can see the battery pic appears on the middle of the black screen.
BUT, like the former situation, no matter how long I charge the tablet, I turn it on and it dies quickly.
SO, my problem is this, and i can't find a tiny reason why my tablet got (or how to fix) this battery problem.
Never seen a battery problem like I have right now.
I got several ideas about this. (Hope this will help you to fix my situation )
1. My tablet's rom is not pure. (But not rooted.)
As far as I remember, I applied the Ukrainian version about 3 weeks before.
Is it possible the this is the reason?
If so, wiping the original rom and applying the new one would help me?
2. Is it possible that the battery and the tablet connection got a problem?
If so, open it by myself and re-positioning the battery would help me?
3. The battery charger part might be damaged.
Then it leaves me the one option {GO TO THE SERVICE CENTER} ?
4. well...not 4.
have no idea.
Using same charger which is official SAMSUNG's.
I will keep monitoring this thread.
Little help to poor man would be really grateful, THX
PS
I just tested download mod.
With the charger is plugged in, it's working.

to see if the charger is bad, fully shut tablet down and then try to plug the tablet into a USB port on a computer and wait about 8 hours, then unplug it and see if the tablet holds any charge (battery might still be low but it should have enough charge to run awhile), if above works then it means you need another wall charger (5v 2.1A).
if it still just powers off or dies then it means the battery is bad or not connected or something else is wrong with it.
1. Try another USB cable
2. Try another 5v 2.1A wall charger
3. Try charging on a PC
4. replace battery.

To verify your tablet is charging, you need this little tool
http://www.ebay.com/sch/i.html?_fro...usb+power+current+and+voltage+tester&_sacat=0
Current should be 1.5 to 1.7 Amps, voltage should be 5 to 5.2 V
If the charging current is under 1.5 A, you should change different USB cable or adapter
If cable and adapter are fine, the next is charging port, it's easy to replace if your is defective.
Never use usb port on computer to charge, it only supply 0.5 A and your tablet needs at least 2 Amps for charging properly.
These are basic steps you need to do, without basic information I cannot tell what is wrong with your tablet: not charging or bad battery, or the worst: bad main board.
The one you have to verify: your tablet is drawing normal charging current around 1.5 to 1.7 Amps when plugged in. You can not troubleshoot problem just by guessing.
The most common problem of Samsung tablets are cracked Battery connector, a simple re-solder will fix the charging problem.
There are many unknowns, you have to eliminate charger, usb cable, usb charging port as the source of problem first. Then next look for battery or battery connector.
Otherwise, you will confuse yourself and others what causing the problem. Elimination is the key to figure out problem from many unknowns, one by one at a time. There's no short cut , otherwise, you can not figure out where the problem comes from.
I see many users send their tablets for service and the problem just comes from a bad cable because they have no idea what's wrong with their tablets.

Beut said:
To verify your tablet is charging, you need this little tool
http://www.ebay.com/sch/i.html?_fro...usb+power+current+and+voltage+tester&_sacat=0
Current should be 1.5 to 1.7 Amps, voltage should be 5 to 5.2 V
If the charging current is under 1.5 A, you should change different USB cable or adapter
If cable and adapter are fine, the next is charging port, it's easy to replace if your is defective.
Never use usb port on computer to charge, it only supply 0.5 A and your tablet needs at least 2 Amps for charging properly.
These are basic steps you need to do, without basic information I cannot tell what is wrong with your tablet: not charging or bad battery, or the worst: bad main board.
The most common problem of Samsung tablets are cracked Battery connector, a simple re-solder will fix the charging problem.
Click to expand...
Click to collapse
You can charge from a computer fine just as long as the tablet is fully shutdown first (so you see the battery icon scrolling), this will ensure the 500ma will go directly to the battery and not running the tablet and os, it will charge very slowly but it will eventually reach 100% as nothing is drawing power from the battery to drain it (though I would only charge to 20%, to see if it holds a charge), however this method is just for diagnosing if the charger is bad and have no current alternatives, obviously this should not be a long term solution and never used when the tablet is running, but rather to see if the battery can hold any charge at all.
if you have another 5v 1+A charger laying around then use that instead., if the charger is the problem you can pick them up pretty cheap off ebay (make sure the hallmark icons and model number match to avoid knockoffs)

otyg said:
if you have another 5v 1+A charger laying around then use that instead., if the charger is the problem you can pick them up pretty cheap off ebay (make sure the hallmark icons and model number match to avoid knockoffs)
Click to expand...
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To see what is wrong with charging problem, you should never use wrong charger like 5V, 1 A or a USB port on computer. If using a 5V, 2A charger and a correct USB , any reading is under 1.5 A, there is something wrong with charger, or USB cable, or USB charging port, or battery connector. Even wrong USB cable, the one has only max of 1A, also is the source of slow charging.

His issue is not with slow charging, it was as soon as he unplugged it the tablet instantly powered off, in this case if the battery is 100% dead then damage is already done and once a lithium battery is completely discharged then most likely no charger whatever the mA is will bring it back...this is why I was saying to charge it from whatever source since you need to get a charge into the battery before it's irreversible damage.
However after re-reading ops post I think it's safe to rule out the charger as the problem because he said he could run the tablet with it plugged in (so that means the Charger is providing enough power to run the tablet) according to my mA reader this alone is around 500-700mA in standard use / full brightness
This also mean we can rule out a bad Micro USB port on the tablet since a broken one wouldn't allow power to the tablet.
the problem likely lies with a bad battery or a bad battery connection, the probably only option at this point would be for him to have samsung service it or take the chance to replace the battery.
(BTW I have all the tools nessasary and I know what can and can't charge this tablet)
Yes I know it needs a 2.1a charger to charge it while it's actively running since a good portion of that power will go into running the tablet and LCD if needed, it does not need a 2.1A charger when it is powered off and 500mA to 2.1mA will still charge it.

Three is a thread here talking about reseating the battery. Look it up. That may help.

Agree with otyg. I recently had a similar problem. My galaxy tab s 8.4 would power off immediately after being removed from power. It would register as having 100% charge while turned off, but once powered on, the tablet would show 4% charged or lower. Another thread on this site mentioned that the battery contacts on the motherboard have cracked for some owners creating symptoms like ours. I resolved the issue by applying a low resistance conductive adhesive to the cracked pins linking the battery to the motherboard. If this happens to be your problem be very careful because there are other contacts next to the battery pins. Good luck!

Charging problems with Nexus 7

Recently I experienced (again) charging problems with my Nexus 7 (2013). Usually they first slow down the charging process, and after some time the tablet even does not see the connected wire anymore. Which is strange (Xperia Arc S still sees it, and is charged at full speed), but that could be due to worn-out contacts, and can be solved by using a new cable.
Recently the charging stopped completely, and even a new cable did not solve the issue, unless pressed with a certain pressure and direction into the USB port, which starts a slow charging. This was tested with three different chargers and four different cables, partly used, partly new.
In order to find the problem (worn-out USB port anyone?) I opened the back cover, and measured the voltage at different places while "charging". The tablet itself tells me that it does not charge, but I measured 5V on the respective pins at the PCB in the inside of the Nexus, and I measured 4V at the connections to the battery. Why does the Nexus still tell me that it does not charge? Apparently the battery gets power, thus the USB port is not faulty.

After my last tablet died from this very problem, I resolved to avoid it with my next one. That's one of the reasons I specifically chose the Nexus 7 2013 as my next tablet: IT SUPPORTS WIRELESS CHARGING!
So, I bought a QI charger along with the tablet. That USB port is going to remain as pristine as possible. You may be able to get around your current situation by doing the same thing.

rofl022 said:
I measured 4V at the connections to the battery... Apparently the battery gets power, thus the USB port is not faulty.
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This is inconclusive. If you measure the battery without USB power, 4V will be still there.
Get one of these to check power supply current draw.