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Want faster charging/Device discharging while charging/not charging? Read within!

Background
Hi all, I, for a very short period of time was suffering from the problem of my phone DISCHARGING while it was charging. This made no logical sense to me until I did some research, which I will detail below.
How USB Power works (Roughly)
Firstly let's discuss USB power provisioning. Strictly speaking, the specifications say that any given USB port should provide a maximum of 500mA (or 0.5A) at 5 volts. *Don't shoot me electronics guys, I'm simplifying for ease of explanations sake*. Imagine that ampage as the actual force of the charger, how quickly it can ram power into your phone. Like the rate of flow on a pipe.
The beginning of the problem
This was all fine and dandy when all USB was really used for was Keyboards, Mice, Memory, etc, low current draw devices. Something else I should mention here is that the Ampage that a port CAN provide is not the Ampage it DOES provide - the device draws a certain Ampage and if the USB controller agrees it outputs said Ampage. Later, when USB was beginning to be used for more power hungry applications, ie External hard drives, these required more power than the port could (In theory) provide. However, most more modern motherboards/USB controllers were more than capable of supplying plenty more Ampage if it was requested. This was breaking the specification but not in any massively dangerous way so as such nothing bad happens.
This is where we get to the actual issue people are experiencing here. The Nexus 4 is a standards compliant device in the respect that it seems to only draw 500mA from any USB port no matter what it's potential, unless it's an AC Wall wart. If you're experiencing problems with wakelocks (see XDA) and other things, this causes your phone to draw more than 500mA which means your phone actually discharges while it's charging! Terrible!
This is quite easy to get around, but again I'm going into detail so let's explain how the phone tells the difference between a dumb wall wart and a USB controller. Easily! The USB controller obviously makes use of the data pins found within the USB cable, whereas a wallwart just (almost always) shorts them out. The Nexus 4 can detect this short, and as such draw more power *While still in quotation marks staying in spec*.
The root problem is not with how the N4 is charging, it's with the wakelock you're experiencing which is causing the phone to draw so much power while the screen is off. While the screen is off and the phone is in Deepsleep (A CPU state where it uses very little power) - it should draw no more than 50mA leaving 450mA for charging the battery, but you guys are probably experiencing a wakelock of some sort.
Solutions to the problem or How to break a specification for the good of mankind
The simple solution is to install this app: https://play.google.com/store/apps/details?id=com.rootuninstaller.batrsaver
This forces the device into a Deep sleep when the screen goes off by killing applications and turning off all internal chipsets that have wakelock capability, most commonly networking on the Nexus 4. This will allow your phone to charge (slowly) off USB without an issue. Another common wakelock is when the device is picked up by your desktop as a media device. The USB controller inside the Nexus 4 forces a wakelock which keeps it from charging. Stupid design, I know.
* A more hackish solution is to install Francos kernel, buy his app, and tick the Fast charging option in the kernel settings dialog. This will force the phone to think that everything is an AC adaptor and will force the phone to draw as much current as it can from the USB port (which on most modern motherboards is fine, and results in extremely quick charging).
* An even simpler solution than all this is to just use a 'USB Charging cable' - this is simply a cable that does not have the Data pins, and as such does exactly the same as what enabling USB fast charge above does. http://www.ebay.co.uk/itm/Micro-USB...487076?pt=PDA_Accessories&hash=item51a465d124
If you live near a Poundland store here in the UK they sell a 4 in one USB cable type thing which turns 1 USB port into Ipod sync connector, Nokia connector, MicroUSB and MiniUSB, and this doesn't have the data pins and as such is excellent.
One final point, an excellent app for monitoring whether your device is actually charging or not and how quickly is Current widget: https://play.google.com/store/apps/details?id=com.manor.currentwidget&hl=en
This widget will tell you how much Ampage is going into or leaving your battery. If the battery icon is green, then it's discharging, if it's black/white then it's charging. The bigger the number, the faster the discharge/charge. This is an extremely easy way to test speed of chargers too.
Recommendations
Another solution, just use an AC Wall wart - they're cheap as hell and the one supplied with the Nexus 4 is an extremely fast charging one. Shame I've gone and lost mine.
A way to roughly monitor charging current draw
I'd also recommend you install https://play.google.com/store/apps/details?id=com.manor.currentwidget&hl=en and monitor, if the battery is green while charging it's discharging and you need a more powerful charger/to figure out what's causing your phone to use so much power.
General good values in Current Widget
I generally saw a max draw of about 750mA for charging (not including draw for powering the device, the Nexus 4 can draw more power to charge and power the device) on my old Rev10 first generation Nexus 4. On my new Rev12 board I'm noticing this increase to about 850mA.
Are higher amperage chargers any benefit to anyone?
Yes and no. You will not notice faster charging unless you use your device while charging. Your nexus will draw as much power as it needs to power the phone while charging at the fastest rate. For example on the stock 1.2a charger
1200mA | 800mA goes to charging 400mA goes to powering the phone idling
Let's say you start a stability test. Your phone will obviously be using a lot more power so this will happen
1200mA | -600mA goes to charging and 1800mA goes to powering the phone stability testing
That minus value above may look strange! Let me explain. If the phone needs more power than the charger can supply, it will draw from the battery. That's the minus number.
If you have a higher ampage charger like for example a 2.5a charger
2500mA | 800mA goes to charging 400mA goes to powering the device
Stability testing
2500mA | 700mA goes to charging 1800mA goes to powering the device
Can you see the difference?
DISCLAIMER: I am not an electronics engineer nor do I claim to be, I am simply a hobbyist and this is what I've found to be the case. Please correct me if I've made any mistakes, I want to learn.

Thanks!
Thanks so much for this post. It's very helpful.

kn100 said:
Another common wakelock is when the device is picked up by your desktop as a media device. The USB controller inside the Nexus 4 forces a wakelock which keeps it from charging. Stupid design, I know.
Click to expand...
Click to collapse
This isn't true for everyone then as mine connects and charges just fine off of my laptop and desktop when connected as a media device. In fact its on my laptop right now charging, gone from 68% to 81% in about 30 minutes and it shows connected as a portable media player.

Great info! Thanks for writing this!
In certain use cases the Nexus4 discharges faster than it charges and this is a very useful guide.
I use my phone for navigation in my car and having the GPS on and the screen at high brightness
drains the battery faster than the 0.5A car chargers can supply. Car chargers rated for 2.0A work well.
I haven't tried a 'USB charging cable' with the data pins shorted, it may work as well.

-Mindroid- said:
Great info! Thanks for writing this!
In certain use cases the Nexus4 discharges faster than it charges and this is a very useful guide.
I use my phone for navigation in my car and having the GPS on and the screen at high brightness
drains the battery faster than the 0.5A car chargers can supply. Car chargers rated for 2.0A work well.
I haven't tried a 'USB charging cable' with the data pins shorted, it may work as well.
Click to expand...
Click to collapse
was over in Nexus 7 forums and the 4.2.x kernel should have solved the problem at least for having to use shorted cables. have to wait and see if 4.2.2 brings any more changes.
http://forum.xda-developers.com/showthread.php?t=1984838
Section 6 in this link is about power supplied through USB
http://en.wikipedia.org/wiki/Universal_Serial_Bus
I can't tell if we have an updated kernel allowing faster usb charging as I'm limited by the power output of the usb port in my laptop. The output (5V at 500mA max) is controlled by the laptop (USB Standards) and it doesn't matter what the phone or cable is capable of as that's the max it will give out and that's about what I'm charging at. If I had a dedicated charging port in my laptop then it would be different and I could see if its able to draw more power. I have a 1.0 amp port in my car and it does charge at the higher amperage, I would assume it would do the same thing if I had a 2 amp usb port in the car. So I think the stock kernel has the fast usb charge built in it just depends upon if you have a usb port capable of providing a faster charger, it has nothing to do with the cable as I'm using a standard unmodified micro usb cable and its able to draw the max a usb device is able to put out.

thanks
thanks for a great detailed post!!!
I have the same trouble with my N4 when I was charging while using my phone...
I find it very slow... I guess I've been spoiled by my previous iPhone (which charges fairly fast)....
i might be stating the obvious but I find the phone charged "a lot" faster when it's OFF
if you are running low with your battery and need a quick 10 min charge, just do yourself a favour by turning off your phone...
the difference is quite significant!

kzoodroid said:
This isn't true for everyone then as mine connects and charges just fine off of my laptop and desktop when connected as a media device. In fact its on my laptop right now charging, gone from 68% to 81% in about 30 minutes and it shows connected as a portable media player.
Click to expand...
Click to collapse
Yup, me too. It only discharges while charging when I am playing like NFS most wanted.
Sent from my Nexus 4 using xda app-developers app

The issue with cables is with the LG usb wall charger as the one supplied isn't capable of getting the 5 volts at 1.2 amps that the charger is rated at, mine is getting around 300 - 400 mA. The micro usb cable I have in my car and use with my laptop (for charging and data transfer) is able to handle the higher amperage, it gets around 1 amp with the LG plug. There are no specs on these cables so I can't list a definitive difference and I would assume that the cable mod in the OP might help with the LG cable. It also might just be simpler to only buy those cables capable of handling higher amperage as obviously they are out there from my experience.

The cable I'm using is an RCA coiled charging/syncing cable model AH732CBR (has data pins). The maximum I'm getting from this is about 870 mA regardless of the amperage of the usb port, I've tried a 1.0, 1.2 and 2.1 and they are all around 870 mA on current widget. I would suppose if I could find a strictly charging cable I could get higher (link to ebay in OP is outdated) but this is still 2x that which I'm getting from the LG cable supplied with the phone which only puts out 300-400 mA. Our phone also has Qualcomm's quick charge which is supposed to improve battery charging times by 40%.
http://www.droid-life.com/2013/02/1...allows-your-device-to-charge-up-to-40-faster/

How do you measure how much mA the device draw from the charger?
Sent from my Nexus 4 using Tapatalk 2

omrij said:
How do you measure how much mA the device draw from the charger?
Sent from my Nexus 4 using Tapatalk 2
Click to expand...
Click to collapse
current widget, link is in the OP

kzoodroid said:
The cable I'm using is an RCA coiled charging/syncing cable model AH732CBR (has data pins). The maximum I'm getting from this is about 870 mA regardless of the amperage of the usb port, I've tried a 1.0, 1.2 and 2.1 and they are all around 870 mA on current widget. I would suppose if I could find a strictly charging cable I could get higher (link to ebay in OP is outdated) but this is still 2x that which I'm getting from the LG cable supplied with the phone which only puts out 300-400 mA. Our phone also has Qualcomm's quick charge which is supposed to improve battery charging times by 40%.
http://www.droid-life.com/2013/02/1...allows-your-device-to-charge-up-to-40-faster/
Click to expand...
Click to collapse
Bit of a late reply but please bear in mind the Nexus will NOT draw anything more than about 800mAh from the wall for charging alone. That is the absolute max and is a hardware limit - If the cable is transmitting that and it's showing in current widget you've got a good setup. See the added section in OP for more info on higher amperage chargers.

[Q] Is any kind of fast charging possible?

Team,
First off, I want to say thank you for creating an amazing resource for these phones. I currently have a Galaxy S4 Active MF3. I bought the phone with the intent of using it in conjunction with my car stereo, which is a Pioneer 8500 BHS. I've paired this up with a Samsung MHL 2.0 adapter and ARLiberator. On top of this, I have installed a OBD-II bluetooth module in the car that also communicates with the phone. The end result is that the phone delivers full touch screen control of all apps on the phone, full bluetooth hands free calling, voice control, GPS (Tom Tom), Pandora, and most importantly, gives me a second dashboard where I can customize any gauge that the car did not offer stock, such as boost gauge, wideband air/fuel ratio, exhaust gas temperature, and a few other things. I'm using the full version of Torque to do this. It is amazingly useful, with one exception. The Samsung MHL adapter never lets the phone charge at more than 300 milliamps. The USB connection straight from the stereo charges at 900, and a 2.1 AMP charger with the Samsung cable will charge at 1900. However, regardless of the combination I use, the MHL always cuts this down to 300. This causes the phone to lose about 15-20% of it's charge every hour. For short trips, this is OK, but for longer trips, I can no longer use GPS, which is a big problem, as that's the whole reason I got the phone. Other users of the standard Galaxy S4 and this combination have been able to get around this issue by installing a ROM with Fast Charge enabled, which gives them 800 milliamps. This is just enough to let the phone be used and slowly charged at the same time.
I understand that currently we're limited to stock kernels with modifications layered on top (GoldenEye, ETC...), and that the Fast Charge code requires a kernel recompile in order to function. Is this correct? Do I have any other options? I've considered wiring in a wireless charger just to get the phone to charge on long trips, but I'm concerned that wireless charging in addition to the USB input and charge may cause the battery to overheat or reduce it's life.
Any ideas?
Thanks in advance,
Matt

as far as I know, there is a possibility of welding a 100 Ohm (or just short circuit (more risky, but I've read that some guys using a standard usb cable with simple bypassed Data-wires in combination with the S4A)) between the D+ and D+ wires of the USB-Cable (should be the green and white wire within the cable). Regarding http://www.usb.org/developers/devclass_docs a resistance below 200 ohm is the sign for a dedicated charging cable/device.
I've seen a manual of an sgs user, having full loading speed in his car, using a modified cable. Unfortunately his manual is in German, u can find it here. All credits belong to him.
by the way, i am pretty sure u will find an similar manual within this xda-board using the right search patterns, cause It does not seem to be device related.

shaDNfro,
Thank you very much for your reply, but unfortunately the 'cable mod' will not work in this instance. The reason that it won't work is that the stereo needs the Data + and Data - for Audio and synchronization data being sent back to the headunit for broadcast, and the MHL blocks the D+ and D- resistance from reaching the phone. To verify this, I took a stock Samsung cable with a voltage inverter in the car, and wired the whole system up into the MHL adapater. The system still charges at 300 ma, despite the fact that I can plug the same cable going into the MHL directly into the phone and get 1900 ma. If I use a 'modded' cable without the inverter, then the MHL still charges at 300 ma, but AppRadio will not function, as it gets no signal from the data ports on the USB. To add insult to injury, the MHL input is a 12 pin interface, and shunting D+ and D- cables on the MHL output is dangerous, as the system is doing more with the 12 pins than a standard 4 pin USB. I really don't want to fry a 400+ dollar phone.
What we really need here is one of two things:
1. The ability to upload a recompiled kernel into the system (I know that we have a bounty on this and it's not going anywhere)
2. The ability to modify the input amperage without a recompiled kernel
I'm not sure if either of the above two things can be done. I'm either going to have to live with this or get a new phone.
If ANYONE has any other ideas, please let me know!
Matt

Is it possible to mod usb cable to take the power directly from car charger?
Connect usb chargin wires to car charger from phones end of usb??
Sent from my GT-I9295 using poor english.

Vaiski said:
Is it possible to mod usb cable to take the power directly from car charger?
Connect usb chargin wires to car charger from phones end of usb??
Sent from my GT-I9295 using poor english.
Click to expand...
Click to collapse
Vaiski,
That's not a bad idea! From some more of my recent research, it appears that I now have three options I can look into:
1. Vaiski's idea of adding a 2.1 AMP second USB line to the + and - phone input while cutting the current MHL + and - cable output. This would essentially allow the MHL to get its power from the stereo's USB input, and the phone to get its power from an external, high amperage USB line and still allow me to keep the data flowing between the phone, MHL adapter, and stereo. I've got a second 'generic' MHL adapter that I wouldn't mind cutting up to spare my $50.00 Samsung MHL adapter if this doesn't work. This wouldn't allow the system to get the full 1900 ma, but it should get me upwards of 300 ma, which is where I am now.
2. I can add a wireless charger into the mix. From what I've read, if you charge with USB and wireless charging at the same time, the wireless charging would take priority. This would give me the same results as option #1.
3. I can try using the samsung S4 Multimedia dock. It appears that the dock doesn't have the same voltage output limitations as the MHL adapter. It does cost $100.00, though, and it's rather bulky.
These are all really great ideas, but what really bothers me about all this is that it shouldn't be necessary. If Samsung/AT&T hadn't installed a bootloader kernel checksum, none of this would matter. I could simply put a custom kernel in and call it a day with my current hardware. Hopefully someone will crack the bootloader soon. That would really be the best option instead of being locked into 4.2.2.
Thanks again!
Matt

s4 active charging
mattb22 said:
Vaiski,
Thanks again!
Matt
Click to expand...
Click to collapse
I don't know whether or not you found a solution to your problem yet. I discovered same problem using stock charging cable and having Bluetooth, Wi-Fi amd GPS turned on, playing music through usb to a pioneer stereo.... no Bluetooth on stereo, but was using a BT hands-free device. Anyway, same problem as you, charger wouldn't keep up. Tried turning off Wi-Fi... had mobile hotspot turned on for wife's tablet, helped some but still drained faster than charged. A couple months ago, I couldn't find the factory charging/data cable and phone needed charging, so I tried a cable from one of those battery powered phone chargers, thing is only about a foot long, but phone said "charging" it went from about 30% to full in less than an hour, this phone has never charged that fast. I've experimented with it a bit, and it won't work as a data cable but it will keep up with everything turned on. I don't know if it's the length of the cable, or if the pins on the cable are different, in any case, try different cables, if you only need charge while your driving then the lack of data won't be a problem, though I liked being able to charge and listen to music at the same time, I'd rather know that my phone won't be dead when I get to the other end of a long road trip.... besides I figured out that a flash drive plugged into stereo plays music better.
Hope this helps

[Q] Does you phone charge directly from your car USB port?

By "directly" I mean using regular USB data cable (most likely USB->Micro USB) and NOT special charge only cable that has data pin shortened to draw higher current.
The reason for this post is that I found that my new phone (Moto X) doesn't charge when connected directly via regular data USB cable even though charging indicator is on. When idle it still loses several %/ hour, when running Google maps - much more.
After Googling I found that if the phone is connected as USB media device it draws less power from USB and it may not be sufficient to charge phones with high capacity batteries. Workarounds include using charge-only USB cables that have data pins shorted, cigarette lighter chargers or AC charger if your car is equipped with AC socket (mine is, but what a pain to have to use it for this!).
Here is my situation on '11 Jeep Grand Cherokee with 430N (2 USB ports, Android phones are recognized as media device on both):
Old phone (Droid Incredible, 1300 mAh battery) charged fine when idle via regular data cable even though it was in media player mode. I haven't really used it when running Google Maps much so can't comment on that.
New phone (Moto X, 2200 mAh battery) doesn't charge via regular data cable (even though indicator shows phone charging). When idle it still loses several %/ hour, when running Google maps - much more. I tried 500 mA cigarette lighter charger and it charges it fine in idle, haven't tried while running Google Maps yet.

The USB power in my truck is provided by one of these:
http://daqstuff.com/400116_5volt_switching_power_supply.htm
The only mod I made was to short pins 2 and 3 on the USB ports, which is required for full current charging with a Nexus 7. Dunno if the Moto X is the same, but it charges just fine when plugged into it.

My Moto X does not charge from the USB port in my Acura. I use a USB adapter in the cigarette lighter if I need to charge it.
Sent from my XT1053 using Tapatalk

Solutions Etcetera said:
The USB power in my truck is provided by one of these:
http://daqstuff.com/400116_5volt_switching_power_supply.htm
The only mod I made was to short pins 2 and 3 on the USB ports, which is required for full current charging with a Nexus 7. Dunno if the Moto X is the same, but it charges just fine when plugged into it.
Click to expand...
Click to collapse
Wow 2 amps. At home my iPhone is good for something! Its 2 amp wort charges the x fast!

Yes all phones charge in my Hyundai but very slowly since its only a regular USB port not a charging port. I use a Griffin dual USB charger instead.
Sent from my Sero 7 Pro using Tapatalk

Moto X does not charge in my Honda or Volkswagen via car's USB port. All my previous phones including nexus 5 did. For Moto X I have to use car charger.
From my Moto X, in your face!

My wife's X does not charge via her aftermarket stereo in her Subaru. I have not tried it in my F-150 though.

Standard USB ports in a PC supply 5V and 550mA which is not enough to charge current smart phones. If you are using apps, 550mA is not enough to maintain the charge level (i..e if you have 90% charge, plug into a standard USB port, and use Google Maps or stream a movie from the internet, your battery's charge will slowly drain. Not as fast as when unplugged, but it will drain).
The X ships with a 1150A adapter. I've used 850mA to slowly charge the phone.
I've not metered the voltage and current coming out of my car's USB port.
I use a dual port USB charger that outputs 2.1A per port. (its either Griffin or Kensington)

I stumbled across this issue when I tried to charge my X in the car. I have an old nokia car charger (had nice thick writes and curly cord) that I cut the plug off and soldered a micro usb plug and a resistor between pin 5 and ground for activating car mode on my SGS2 (i9100). I plugged in the X, nothing. I did some research and found that shorting D+ and D- puts it into AC fast charge mode. Charges fine with the screen on. Luckily the old nokia charger has enough grunt to cope.
swyped from my JB GT-N8000 with TapatalkPRO

Yep
Interesting. Mine does charge via the USB cable on my aftermarket head unit, but it is fairly slow. All I care is that it doesn't drain the battery at all for 4 hours car trips while streaming music and running Google Maps with the screen on the entire time.

mine slowly/medium charges with MyLog and CarHome Ultra or Nav.
I have a magnet and SkipDot in my car dock to auto unlock and trigger car mode which launches CarHome Ultra. I use Llama to further trigger and enable bluetooth and gps as well as disable WiFi. bluetooth connecting to my JVC head unit triggers My Log and automatically logs journeys for tax. Llama cleans up and turns of gps/bt which causes MyLog to finish too.
swyped from my MOTO XT1053 with tapatalkPRO

Issue when connected to computer! Help!

Yesterday I've received my Tab S2 8.0". After the first charge I connected the tablet to my computer to upload some files and I get a red "X" on the battery and the message: "Slow charger connected"
In the notification area I get a constant red "Device charging slowly. To charge faster, use the original charger".
Is this normal? Cause I'm using the USB cable that came with the device and tried with USB3.0 and USB2.0 with the same results.
Oh, extra info! The tablet was bought in France, I'm from Argentina.

XinsaX said:
Yesterday I've received my Tab S2 8.0". After the first charge I connected the tablet to my computer to upload some files and I get a red "X" on the battery and the message: "Slow charger connected"
In the notification area I get a constant red "Device charging slowly. To charge faster, use the original charger".
Is this normal? Cause I'm using the USB cable that came with the device and tried with USB3.0 and USB2.0 with the same results.
Oh, extra info! The tablet was bought in France, I'm from Argentina.
Click to expand...
Click to collapse
Yes it's normal.
USB ports cannot put out as much current as a decent charger (like the one the tablet came with). Hence it charges more slowly using USB (or indeed some inferior or lower powered plug-in chargers), and it's warning you that it is doing so. I think the maximum a USB2 port can provide is about 500mA, with USB3 about 900mA or so.
Compare that to the proper plug-in charger, which is 2A (if I remember correctly).
Some motherboards etc do have higher current USB ports for charging etc, but that's non-standard and they are usually specially labelled as such.

Oh, thanks for the help. I got a little scare with the warning.

I got the same tablet, and also noticed this warning about battery charing slowly, and asking me to use original charger.
It's working resonably ok with original charger, though it charges slow with other chargers with the same AMP rating. E.g. it charges slowly with the larger iPad charger, which is also 2 AMP rated ...
Charing with iPad charger is so slow, that when I use the device with during charging, it drains faster than it charges! Quick unusual ...
Anyone? Any comments?

Theres an excellent app called Ampere which gives you info on the tablets charging and power consumption - useful and interesting.
Cant post links yet so just search for it on Play

Also don't forget that (when not built-into the charger) the cable is also important to the amount of current reaching the tablet.
The best charger in the world may well struggle if a long cable with hair-thin high resistance wiring is used to transfer the power into the tablet.
Lastly even though many chargers are labelled as 5v 2A, they may not actually be able to provide that under load, and if things drop when a hungry device like a tablet is connected then things will slow up.
I have a few 5v 2A chargers which come up as slow charging, whereas others which were more purposefully designed (e.g. the 5v 2A charger from my old Nexus 7) work just as well as the supplied Samsung one.

DarrenHill said:
Also don't forget that (when not built-into the charger) the cable is also important to the amount of current reaching the tablet.
The best charger in the world may well struggle if a long cable with hair-thin high resistance wiring is used to transfer the power into the tablet.
Lastly even though many chargers are labelled as 5v 2A, they may not actually be able to provide that under load, and if things drop when a hungry device like a tablet is connected then things will slow up.
I have a few 5v 2A chargers which come up as slow charging, whereas others which were more purposefully designed (e.g. the 5v 2A charger from my old Nexus 7) work just as well as the supplied Samsung one.
Click to expand...
Click to collapse
this is such onfortunate ongoing issue
i got my Tab S2 - SM-T715Y in Thailand as i am backpacking Asia ..
I know the warranty is per country .. so I can not use it where I am now - in Vietnam .. or back home in USA
I realized that this was a major factor before buying .. so I can go through my credit cards extended warranty ..
in the future I will buy Acer or Asus or alike that have international warranty ..
yesterday I was on a road trip
and I was using my 12V car charger
and then a battery bank .. and I think it rigered this problem or fact that I drained my S2 to 0%
fact is that now it is showing "slow charger connected" .. I am using the original charger and cable
now it is slowly *discharging* when connected to AC!!
also will try to whipe the cache..
this is so terrible
I am losing faith in Samsung :/ (had charging issues with my Note 3 .. 8 months in .. motherboard issue)
I can not find a solution to this problem
I am thinking of putting it in a refrigirator? maybe it will do something to the battery?

Note 9 Charges Faster When Fast Charge Is Disabled

I've been having a repeatable problem. I have a Note 9 that will charge faster when I disable fast charging under battery settings. I tested the load being drawn with a USB Power meter these are the results I got.
Using a USB-A to USB-C cable:
When QC is enabled:
Phone draws 0.5amp charge, 10ohms resistance at 5.02V.
When QC is disabled:
Phone draws 1.2 amps, 3.9 ohms resistance, at 5.02V
I am using the same cable, same power bank. The power bank's USB-A port is able to draw ~1.9 amps at 5V, tested using a USB Meter and Load Tester that will put the USB under 1 amp and 2 amp loads at 5V, with resistance being ~2.7 ohms without the power bank turning off. I haven't tested the power bank at 9V, I don't have a 9V load tester
When I immediately switch from QC to non QC, the results above are repeatable.
Things I Have Done So Far:
Reboot Phone
Clear Phone Cache
Reboot Into Safe Mode
Try Different Charging Cables, Blocks, including OEM parts.
Every once in a while, it will switch back to being able to QC fast charge but it is random.
If I use a Power delivery capable block charger, it will charge at ~2750mA (I dont have other numbers like amps, voltage, or resistance, I'm still waiting on a USB-C meter)
My phone's wireless charging has no problem operating at it's max capacity
Any one else have this problem? Anything else I could do before I factory reset my phone?

I posted about losing Fast Charge thru the stock cable a while back and got no answers or a fix. I have not tried turning off the option to see if it charges any faster. It takes almost 2 to 3hrs to fully charge at this point. I'll take any fix or work around at this point.

TokedUp said:
I posted about losing Fast Charge thru the stock cable a while back and got no answers or a fix. I have not tried turning off the option to see if it charges any faster. It takes almost 2 to 3hrs to fully charge at this point. I'll take any fix or work around at this point.
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Turning off fast charge made my charging a bit better. With Fast Charge (FC) turned on, I was getting 0.5amps (gave around 400-500mA). Turning FC off, sped up my charging by 50%, charging at 1.2 amp (roughly gave me 800-1000mA; Both charges were at 5V). Im able to charge at around 1000 mA with this setup, a little less than wireless quick charge. No idea why turning it off helped.
Another workaround that brought my charging speed WAY UP, to 2500mA, was buying a Power Delivery (PD) capable block WITH A USB-C to USB-C cable. I can get normal fast charging speeds with that setup.
I cant get FC with USB-A to USB-C cables, which is frustrating as most of my charging blocks are the regular USB-A input port.
Hope this helps you. 2-3 hour charge is brutal.

What's even weirder is in my car my phone would barely charge. But since I lost FC at home, it started working in the car. So in my car I can FC but not at home. I even tried the wire I use in the car and still nothing. Idk what is going on

Is it possible that turning off QC is turning off a regulation in the software to keep the battery from overheating? With this regulation turned off that would normally be on when quickcharging, the regulation is not active, thus causing the battery to charge at a less regulated speed, causing charging to be faster? Maybe there's a QC bug currently that's hampering it's full potential? What software version are you guys currently?
I just checked QC on mine on the latest Xfinity version and no matter what charger or cable I use with the function, it is working.

It's def not a software thing. I'm on latest October patch. Samsung told me that they have seen some issue with the charging port and once it goes bad there is nothing to do but replace it. They told me to bring it in to a store for repair thru my carrier. Haven't had a chance to go.

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Jammol said:
Is it possible that turning off QC is turning off a regulation in the software to keep the battery from overheating? With this regulation turned off that would normally be on when quickcharging, the regulation is not active, thus causing the battery to charge at a less regulated speed, causing charging to be faster? Maybe there's a QC bug currently that's hampering it's full potential? What software version are you guys currently?
I just checked QC on mine on the latest Xfinity version and no matter what charger or cable I use with the function, it is working.
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That what I was thinking. Something is actively limiting the charge coming in. Everytime I had quick charge enabled I've been monitoring the ohms and the resistance would automatically jump to 10ohms. Then I disable QC and the resistance automatically drops to around 6 ohms.
I'm running Android Pie 9.0, Kernel version 4.9.112

TokedUp said:
It's def not a software thing. I'm on latest October patch. Samsung told me that they have seen some issue with the charging port and once it goes bad there is nothing to do but replace it. They told me to bring it in to a store for repair thru my carrier. Haven't had a chance to go.
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Click to collapse
Nocturncal said:
That what I was thinking. Something is actively limiting the charge coming in. Everytime I had quick charge enabled I've been monitoring the ohms and the resistance would automatically jump to 10ohms. Then I disable QC and the resistance automatically drops to around 6 ohms.
I'm running Android Pie 9.0, Kernel version 4.9.112
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Click to collapse
Yeah it could definitely be hardware related as well, due to each pin on a type c charging serving different purposes. There are two specific pins(I think it's two), that are responsible for enabling higher input of electricity. Couple years ago Google made comments about the cheap Amazon knock off cables and why they failed after a short while. Wouldn't surprise me if Samsung cheaped up for the cables and port on the device. I'll have to try and find the articles I read concerning the pins.
Here's a good start to understanding Type C.
https://www.allaboutcircuits.com/te...pe-c-which-pins-power-delivery-data-transfer/

Its the **** cable they supply with the phone.
I had all the same problems.
I noticed that when I turn off quick charge the phone can charge at 5v 1.7 amps. (USB doctor).
When I turn on quick charge it can only charge at 5 volts 0.40 amps.
The phone is trying to charge at 9 volts but for some reason cant so it goes into this safe mode.
I purchased a new Samsung cable it lasted for a week and developed the same problem.
A hint when it develops this problem Dex stops working.
I tried all kinds of cables. One Plus 5, and a few others. I finally got it to work again with my wifes one plus 6 cable.
Im now researching USB Type C ports and USB standard 2, 3, 3.1, 3.2
As well the quick charge tech used by Samsung. Its not Quick Charge 2. Its a proprietary standard.
So if your having problems with quick charge it could be due to your cable or your Port. Things very rarely go wrong with the charger. Also get yourself a USB Doctor. Its a big help. And only costs a few bucks.
Hope this helps somebody out there.
Right now I am trying to compare Note 9 vs Note 20 USB cable.