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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.
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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.
Hi all, I have never experienced this kind of wierd issue with any of my past phones. When i would play games or say watch a movie on phone,( my last one was Htc One X), i would usually connect it to a charger so that the battery keeps charging slowly, and it worked with each of my past and even my gf's galaxy s4. But with XZ, the battery keeps continuously discharging. Anyone got any fix for this? With the kind of weak battery XZ has, it is a highly needed basic feature. I even tried with a 2A S4 charger, but to no effect. I even tried the modding of usb cable by shorting the data wires (the green and the white wire cut and insulated), still no improvement.
I have been using existenz v1.5.5 kk, and i can see that there is an option of fast charge in performance control. But turning it on doesnt make any change. Does the kernel not support fast-charge?Can anyone share any insights? It feels stupid to have to lay the phone down letting it to charge by itself olny to get all discharged within 3 hours.
billamin said:
Hi all, I have never experienced this kind of wierd issue with any of my past phones. When i would play games or say watch a movie on phone,( my last one was Htc One X), i would usually connect it to a charger so that the battery keeps charging slowly, and it worked with each of my past and even my gf's galaxy s4. But with XZ, the battery keeps continuously discharging. Anyone got any fix for this? With the kind of weak battery XZ has, it is a highly needed basic feature. I even tried with a 2A S4 charger, but to no effect. I even tried the modding of usb cable by shorting the data wires (the green and the white wire cut and insulated), still no improvement.
I have been using existenz v1.5.5 kk, and i can see that there is an option of fast charge in performance control. But turning it on doesnt make any change. Does the kernel not support fast-charge?Can anyone share any insights? It feels stupid to have to lay the phone down letting it to charge by itself olny to get all discharged within 3 hours.
Click to expand...
Click to collapse
Charging is really a problem for XZ. Anyways, shorting the data wires won't help, try switch to a stronger cable that's capable of transferring larger amount of electricity when you're using the 2A charger (many of those cables aren't able to transfer enough amount of electricity).
Also, when your phone is really fully loaded and became very hot, just as when you use it for navigation in your car under the sun, the charging speed will decrease (I don't even know why). The charging speed decreases either when you're touching the screen or when it's hot.
Anyways, try better cables first and see if it helps. The docking system is also likely to charge faster.
Darren_J said:
Charging is really a problem for XZ. Anyways, shorting the data wires won't help, try switch to a stronger cable that's capable of transferring larger amount of electricity when you're using the 2A charger (many of those cables aren't able to transfer enough amount of electricity).
Also, when your phone is really fully loaded and became very hot, just as when you use it for navigation in your car under the sun, the charging speed will decrease (I don't even know why). The charging speed decreases either when you're touching the screen or when it's hot.
Anyways, try better cables first and see if it helps. The docking system is also likely to charge faster.
Click to expand...
Click to collapse
I used a whole bunch of cables. The HTC one actually works as an anti-charge cable lol, it eats up battery even when the phone is left on charge unused. I had high hopes with the S4 cable, which turned out to perform same as the stock Sony one. Guess I have to live like this..
billamin said:
I used a whole bunch of cables. The HTC one actually works as an anti-charge cable lol, it eats up battery even when the phone is left on charge unused. I had high hopes with the S4 cable, which turned out to perform same as the stock Sony one. Guess I have to live like this..
Click to expand...
Click to collapse
Sorry to hear that the cables you tried all failed. Did you try using the docking system? They should perform better though.
I mentioned switching cables because I had a "anti-charge" cable before, lol. I did some research afterwards and finally got some 22AWG cables and they really made a difference. It's said that they're capable of transferring 3A electricity and it's really different from all other cables I've used. They're just about $2 each because they're handmade, I can give you one if you wanna have a try.
Also, charging by AC power should be better than using the power of cars' lighter. I'm using my docking system with the SONY stock charger w/ ac power. Never disappointed me.
Darren_J said:
Sorry to hear that the cables you tried all failed. Did you try using the docking system? They should perform better though.
I mentioned switching cables because I had a "anti-charge" cable before, lol. I did some research afterwards and finally got some 22AWG cables and they really made a difference. It's said that they're capable of transferring 3A electricity and it's really different from all other cables I've used. They're just about $2 each because they're handmade, I can give you one if you wanna have a try.
Also, charging by AC power should be better than using the power of cars' lighter. I'm using my docking system with the SONY stock charger w/ ac power. Never disappointed me.
Click to expand...
Click to collapse
Dude you might not be able to give me even if you wanted to.. I am in india and the shipment cost will be excessive. Thanks a lot btw.
I flashed Carbon KK rom and the charging is comparatively better. Atleast it doesnt drain while i use the phone for browsing etc, connected to a wall charger. But if I play games or watch videos on speaker, it does to some extent. I bought one more charger, a Nokia made 750 maH charger (AC 20N) which again is wierdly same in performance compared to both the 1.5A Sony and 2A Samsung. What I think is as you said, the wire makes all the difference. A 2A non detachable is the need of the moment for XZ it seems..
Anti-charge cable?
Xperia™ Z (C6602) with Tapatalk
From my experience usually Google Play Services is the culprit for hot phones and battery drain. What I did when on stock 4.4.2 was i uninstalled updates for the services and my battery life improved by a lot. Although it does come with the downside that some apps like youtube won't work with the older version (easy work-around by using chrome to go to youtube instead =P)
Since I own that phone, I've been facing the same problem of slow charging speed (actually discharging when using some applications)
The more problematic case in when I'm using the phone in car when driving even if I'm using a powerful car charger (Anker).
In the past I also have tested number of diffferent charger and cables (including original Sony car charger) without seeing *any* improvement.
Recently I've decided to took time to make a comparison test with a colleague Nexus 5. We have connected it in my car to the same charger and used in the exact same configuration (Waze navigation app running) for a one hour drive on the same work->home daily path where I use usually my Xperia.
The measured results have shown for the Nexus a 30%/hour increase of battery level opposed to the Xperia 10%/hour decrease I'm facing every other day.
Later, using "Android tuner" application battery monitoring tools, I've been able to measure that, even when using a 2.2 Amp capable charger, the Xperia isn't able to "suck" more that 700/800mAmp input current most of the time.
To go further I've asked in the french forum where I've posted those figures if any people had been successful to have the Xperia battery level increasing in the same configuration. I have got only answers of other people acknowledging having the same problem as myself.
Then I've also asked people in the "accessories" section of a car owners (Toyota) vehicle forum: found people having the same issue are also owning Sony models.
Also asked another colleague who who owns a Xperia model Z1: ditto.
I definitively start to think that there is a defect is a in the battery charging regulation system of the whole Xperia range.
BTW: I will be very interested if anyone using an Xperia Z in car with navigation application running without those issues could post details about his charger brand and model, and how much battery percent/hour increase he his actually getting with that setup.
Sorry for the long message and thanks for your attention
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?
Hi,
I noticed that my Huawei P9 does not charge or charge is low when i'm using it.
This is espacially disturbing when I drive and I use Waze and Spotify.
I checked my Chargers and they all deliver a 2.4 A.
I noticed this with the official usb câble and with anker câble.
Did you have the same issue ? Do you know how to fix this ? I haven't these problème with my Honor 7
Thanks in advance.
Sylvain
i have the same issue when i use Maps. it's slow charging. other than this is fine.
The same for me, too. I used Waze on my holiday, and the charging speed was approximately 10 or maximum 15 percent per hour.
Have you tried the official charger?
I have experience with phones choosing to charge 1A or lower with chargers they don't like (eg. chargers not offcially supported)
I have a car charger, 2.1 A.
I tried with the official charger but the problem remains.
I also noticed that it occurs when I use an external battery which deliver 2,4A. I assumed that the phone managed the charge like this to avoid overheating but I would prefer that it charge a little bit faster when I use the GPS to no loss any percent of battery
Huawei Quick charge
I have the same issue, well i use too, i was using the original charger that came with the phone, i noticed when my battery was very low and playing Critical Ops (an FPS game on Google store) that my battery would just die out. Best solution to this is to buy the Huawei Quick charger which you can find on EBay, maybe Amazon, it's about $10-13 but it's worth it, charges the phone to 100% in an hour or less and you won't have the issue anymore.
I solved the issue cooling down the phone.
The phone has a silicon cover and was placed against the windscreen. During sunny days It was getting very hot until I received the message it was shutting down some features due to very high battery temperature. Then I placed the phone keeping the cover in front of an air vent with air conditioning on and the battery temperature went down below 30 Celsius degrees while charging.
Now with Waze running and Deezer broadcasting through Bluetooth, it's able to recharge from 50% to 90% in almost half an hour. Hope this helps.
Thanks for your reply.
I will try to buy a car charger with quick charge.
I already use a ventilation car mount so the phone remains cool. I will try to change the position to have a better cooling
So I do understand that the Note 5 has fast charge and normally we should leave it enabled to enjoy the charging speed. But the thing is, when fast charging my phone heats up very fast and although it does charge fast, I feel like it could have a negative impact on the battery. So recently I tried turning the fast charge option off (in the battery settings). I expect it to charge normally like when you plug in a non-fast charge adapter, like the one from Note 4 for instance, but it's very very slow. Measuring via ampere it shows ~480 for a couple first minutes, then it drops to ~180 for the rest of the time, then the phone even shows a notification of charging slowly. And that's using the original fast charge adapter, even. Not sure what's happening here. Anyone has a similar experience?
Cables make a world difference when it comes to charging. Are you using the original cable as well ? If you use ampere , and try different cables , you will see that the same charger , outputs different values , depending on the cable. It is also normal for the mA to reduce as the battery gets closer to 100% So a lot of things affect the current at which it is charging.