Anyway to charge at ~2 amps from computer? - Nook Color General

Hi!
I just got my Nook and when I was about to charge it I realised I've lost my adapter for US plugs. Charging from the USB port on my computer is ridiculously slow, even with the Nook's USB/charger cable, and plugging it into my HTC charger makes that charger disconcertingly hot.
I reckon my computer's USB ports should be able to manage to provide at least a couple of amps, but, if I've understood things correctly, it won't provide anywhere near that much to the Nook unless the Nook asks for it.
So, is there any way to make the Nook ask for more juice?
Thanks in advance!
-- P

Animec said:
Hi!
I just got my Nook and when I was about to charge it I realised I've lost my adapter for US plugs. Charging from the USB port on my computer is ridiculously slow, even with the Nook's USB/charger cable, and plugging it into my HTC charger makes that charger disconcertingly hot.
I reckon my computer's USB ports should be able to manage to provide at least a couple of amps, but, if I've understood things correctly, it won't provide anywhere near that much to the Nook unless the Nook asks for it.
So, is there any way to make the Nook ask for more juice?
Thanks in advance!
-- P
Click to expand...
Click to collapse
USB ports are hardware limited to 500mA. It is part of the specification. Also most USB cables can't handle more current than this without damage. The Nook Color has a special cable with extra pins to handle the ~1900mA that it's charger puts out. The Nook doesn't 'Ask' for more juice, it's charger is capable of more current than a standard USB port, and the cable has the extra pins that carry the extra current. B&N did make it so that you could also charge it via standard USB-albeit more slowly. Your HTC charger is getting hot because it wasn't built to self-limit current to prevent damage to itself.

Ah, my bad. I read somewhere that USB devices can start out at 100 mA and then ask for more, but I don't know how I figured it could be as high as several amps >_< thanks for the clarification

mrmark93 said:
USB ports are hardware limited to 500mA. It is part of the specification. Also most USB cables can't handle more current than this without damage. The Nook Color has a special cable with extra pins to handle the ~1900mA that it's charger puts out. The Nook doesn't 'Ask' for more juice, it's charger is capable of more current than a standard USB port, and the cable has the extra pins that carry the extra current. B&N did make it so that you could also charge it via standard USB-albeit more slowly. Your HTC charger is getting hot because it wasn't built to self-limit current to prevent damage to itself.
Click to expand...
Click to collapse
Not really.. most laptop usb ports can handle ~800/900ma just fine. i.e. with my evo, it normally charges at 500ma using a standard microusb cable.. but if I use a special charge-only cable (middle pins are shorted out), then it charges at ~800ma..
-mark

diomark said:
Not really.. most laptop usb ports can handle ~800/900ma just fine. i.e. with my evo, it normally charges at 500ma using a standard microusb cable.. but if I use a special charge-only cable (middle pins are shorted out), then it charges at ~800ma..
-mark
Click to expand...
Click to collapse
Not surprising:
http://www.maxim-ic.com/app-notes/index.mvp/id/3241
What Your Mom Didn't Tell You About USB
With any standard, it's interesting to see how actual practice diverges from the printed spec or how undefined parts of the spec take shape. Though USB is, with little doubt, one of the best thought out, reliable, and useful standards efforts in quite some time, it has not been immune to the impact of the real world. Some observed USB characteristics that may not be obvious, yet can influence power designs, are:
USB ports do NOT limit current. Though the USB spec provides details about how much current a USB port must supply, there are mile-wide limits on how much it might supply. Though the upper limit specifies that the current never exceed 5A, but a wise designer should not rely on that. In any case, a USB port can never be counted on to limit its output current to 500mA, or any amount near that. In fact, output current from a port often exceeds several Amps since multi-port systems (like PCs) frequently have only one protection device for all ports in the system. The protection device is set above the TOTAL power rating of all the ports. So a four-port system may supply over 2A from one port if the other ports are not loaded. Furthermore, while some PCs use 10-20% accurate IC-based protection, other will use much less accurate poly-fuses (fuses that reset themselves) that will not trip until the load is 100% or more above the rating.
USB Ports rarely (never) turn off power: The USB spec is not specific about this, but it is sometimes believed that USB power may be disconnected as a result of failed enumeration, or other software or firmware problems. In actual practice, no USB host shuts off USB power for anything other that an electrical fault (like a short). There may an exception to this statement, but I have yet to see it. Notebook and motherboard makers are barely willing to pay for fault protection, let alone smart power switching. So no matter what dialog takes place (or does not take place) between a USB peripheral and host, 5V (at either 500mA or 100mA, or even maybe 2A or more) will be available. This is born out by the appearance in the market of USB powered reading lights, coffee mug warmers, and other similar items that have no communication capability. They may not be "compliant," but they do function.
Click to expand...
Click to collapse

I'll echo the fact that while USB as a spec isn't limited though sometimes a computer manufacturers will place a limit on it. MacBook Airs won't put out more than 500ish, for instance. The reason for that, I believe, is because Apple wanted to keep the power brick as small as possible (it's significantly smaller than the MacBook Pro's), which meant that the maximum wattage passing through the brick was limited. Since Apple didn't want the MBA to use more power than it could pull through the cord, it limited the power output of the USB ports. I've never needed more than 500 before I got the NC, so I never really cared (and I still don't).
But it is a thing.

Animec said:
Not surprising:
http://www.maxim-ic.com/app-notes/index.mvp/id/3241
Click to expand...
Click to collapse
And, for example, some motherboards have a feature that is a perfect example of bending the standards.
http://www.gigabyte.com/microsite/185/on-off-charge.htm
http://semiaccurate.com/2010/04/23/gigabyte-launches-charge-apple-products/

So, the HTC charger charged it from non-booting to full (ish) charge in 3 - 4 hours, and this time it didn't feel particularly hot. Not sure how or why, but this is certainly a relief

Why not just get a new adapter, they're not expensive.
Sent from my NookColor

Related

Friend purchasing nook for me. Should I get anything else?

I have a friend who is visting the US (I'm from Canada) and I asked him to pick me up a nook. Not finding clear info in some of the reviews, mainly concerned about charging.
This charges over usb when hooked up to your computer right? Just want to make sure it doesn't use a proprietary cable for charging. I read on the ipad side, that older computers don't give out enough power to charge over usb, is that an issue with the nook?
What adapters/cables does it come with exactly? And is it just a standard mini-sub for the charging?
Also, this has a headset jack correct? I've read no bluetooth, I guess there's no way to get a mic working on this then.
Micro USB, will charge VERY slowly using a computer. Includes a 2amp wall socket and special cable to quick charge (still micro usb, just more pins). Has a headset port but does not come with a headset.
I've only had a few mobile devices. I read the ipad can charge over usb if the mobo supports giving out that extra juice. Some mobo's have a new firmware update to enable this.
The connector is micro-usb but just more pins. Hmm. so if the cable breaks or I misplace it no other micro-usb will charge it?
edit: i read a little more and found that it's 30 pin proprietary cable to speed up charging. I also read the galaxy tab does something similar.
Does anyone know if they use the same pin configuration? probably not, but I can get tab usb cables here.
I know you didn't ask for it but I'll tell you anyway
In case you are worrying about registering your device (mandatory at initial setup).
I'm NOT in the US and it worked fine.
Good to know. Thanks.
But I'm more concerned about charging it and relying solely on their cables.
I read the ipad can trickle charge on newer computers but some wouldn't provide enough power. Asus et al have released utilities to increase the power to the usb ports.
I can't post the links but endgadget has an article about it providing links to those utilites. They just talk of apple devices but does this work with the nook?
It comes with a charger for US-type sockets and only if you charge your nook with this (and yes, it is proprietary ) it'll charge quickly. It does seem to charge when you connect it to a standard PC USB port but at an extremely low rate.
On the device Micro-USB (not Mini) is used.
You say it does seem to, do you mean from personal experience? How slow? It sounds like that if you do own one it was so slow you didn't let it finish.
Like if it's 8hrs overnight, I can live with that, but I want to confirm that there is a plan b and not solely rely on their cables.
And as I mentioned asus and others released utils to give more power output to the usb (although these seem like their were only created for ipads). Wondering if those utils speed things up.
for ex, google asus ai charger to see what I mean.
I received my nook Color a mere few hours ago so I can't tell you a lot about its charging behavior It "seems" to load slower via standard USB... if you want to know about the details check one of the large threads on the NOOK and its rooting. I remember reading some information about the USB connector and its peculiarities there.
Ah you just got it. I see.
I found this on the root thread:
'
"There are 12 pins coming off the connector. It looks like there are no pins for the standard micro USB portion, only the extended 12 pins. 2 pins are used to bring in +5V, 2 pins are for signal ground providing a hefty circuit for the 2A charging. USB takes up two pins, and as far as I can tell 2 more are for each LED via current limiting resistors. Two more pins go to discretes that I haven't identified, and two more pins are unconnected. I'll take my scope to them when I have some time."
Not sure what he means when he says no pins for the standard micro portion...
Maybe the plug doesn't have standard USB pins, but the NOOK itself does have standard USB pins as well as the proprietary ones. Because I have trouble inserting the original B&N plug, I went out earlier today and bought a standard Micro USB cable...
I connected it to the nook and it said "not charging", so I went out to do some shopping (10-20 minutes max) and left it at 89%... when I came back it was at 93 %.
So it DOES in fact seem to charge albeit slowly.
Thanks. It's weird, lots of comments of its own cable not fitting properly.
As long as it charges with a normal cable I'm good.
I guess it is charging... however there is a slight chance, that it's NOT charging and the battery charge display is lying (de-calibrated). I don't think so, but I'll only know for sure after a few more days of using only the standard USB charger cable.

[Q] Faster USB Charging?

Just reading up on USB chargers, and I found somewhere in a thread here about phones defaulting to smaller ma when charging via USB if the connector didn't have the data pins shorted or something.
So, I was wondering a couple of things:
1) If the default charger supplies 700ma, do you think that is the most the Nexus S can draw? Does anyone have one of these shorted USB chargers? Does it charge the NS faster?
2) If it does charge faster, how hard would it be to do something similar to shorting the data connections? I have a generic AC-USB cable which I currently use for my iPod touch.
3) Is there a way to check if it is already shorted out? The USB charging port looks similar to ones on my computer, but I'm not sure what to look for.
Thanks for any help! Maybe if we can sort out this stuff, we can provide a solution for those looking for faster charging!
it does work safely, i'm using a 1000 mAh charger at home, and a 2000 mAh charger in the car both are from aftermarket eBay/DealExtreme charges.
no overheating
and charges faster than stock
AllGamer said:
it does work safely, i'm using a 1000 mAh charger at home, and a 2000 mAh charger in the car both are from aftermarket eBay/DealExtreme charges.
no overheating
and charges faster than stock
Click to expand...
Click to collapse
Ok thankyou for that AllGamer, I'll think of possible ways I could mod the charger now
The only reason it is slow is because of the USB charging brick instead of just a charger.
Sent from my Nexus S using XDA App
I know it's a wrong thread, but anyone has any pointers as to how to short a regular USB cable to make the phone think it's a power adapter cable?
XBOHDPuKC said:
I know it's a wrong thread, but anyone has any pointers as to how to short a regular USB cable to make the phone think it's a power adapter cable?
Click to expand...
Click to collapse
Nah it's not the wrong thread that was one of my questions! I'm not sure exactly where you would do it, but maybe if you skinned the wire, then cut the data lines it would work?
Not sure which end you would do it on however, but that may not matter. Any other ideas?
The two center pins in the USB carry the data. If you pull them out, the cable won't be able to connect to the computer.
Sent from my Nexus S
Wow - you don't need to do this and you wouldn't want to in a computer anyway.
The USB specification says that 500ma (@ 5v) of current should be available from a computer's USB port. Of course, the actual wires can carry much more than this, so manufacturers can tell their phones to takes as much current as is offered.
Almost all computers limit their USB power output accordingly - this is why some opld usb-powered external hard drives needed 2 USB plugs to get enough power. The only computers that I am SURE emit significantly more than 500ma on their USB ports are first and second generation MacBook Airs.
Some phones, the N1 and every other HTC specifically, look for a specially shorted cable to "know if they are plugged into the wall adaptor" as opposed to a computer USB port. In reality, this is just a way to make you specifically buy HTC chargers as opposed to third-party off-brands, because plugging one of these phones into an off brand charger will limit the current draw to about 450ma.
If you want to know if your Android phone thinks that it is in "USB" mode or in "AC" mode, just plug the phone in, open the dialer, enter *#*#4636#*#* and then select battery info. If your phone is one that cares (not all do), it will say USB if it thinks it should be in USB charging mode, or AC if it thinks it should be in AC charging mode.
I would not try shorting out the middle pins in a cable and then plugging it into the computer. First, most will probably just disable the USB port completely, shutting off even power you could draw. Second, if it doesn't shut down, you run the risk that a badly-built USB port might not properly limit the current to 500ma - and since they are not designed to furnish more current than that, you might melt something expensive or start a fire. third, if you make a mistake, you risk shorting out either your phone or your computer, which might ruin your day, week or month, depending on your financial means to replace the system that cooks itself.
I would just run out to your local store, pay 15 bucks for a 2A third-party usb charger brick, and go to town. That will work perfectly - this is what I use, and it probably cuts the charge time by 30-40%. Obviously, this indicates that the NS is not capable of drawing a full 2A - I have not put a meter on it, but I would bet that it limits itself to somewhere just under an amp in.
I have recently bought both a 2A wall charger and car charger and my phone does not recognise either of these as anything more than a 500mA source.
Is it really just a case of opening the car charger up and shorting out pins 2 & 3? they are currently not connected to anything in the charger.
If it's indeed a matter of shorting the data lines, then I think you can skin the wire as suggested by others, but then cut the data lines, short the end that leads to the phone, leave the end to the computer open. I think it's the phone that tries to determine whether the data lines are shorted.
Edit: Can someone measure the continuity between the data pins with the stock charger? I wonder if they are shorted. I'm still waiting for my Nexus S to arrive, so can't test it.
Yup, the data lines in the stock Nexus S charger ARE shorted.
I just modified a cheap 1A car charger by popping it open, soldering the 2 data lines together and putting it back.
The report on the Nexus S before I did this (*#*#4636#*#*) said "USB", and afterwards it now says "AC".
I will report back after I make a road trip if this improves the GPS + Pandora + Screen in car situation. I suspect it will.
----------------
Yup, the car charger seemed to actually maintain and increase the battery this time. Seems good.
The NS supports chargers output to a max of 1000mA, as it says on the back of it, where the battery resides.

NC charger

I was wondering where to get a charger for my NC, whether it be car or home, that will not be 30 like in the stores.
smayer85 said:
I was wondering where to get a charger for my NC, whether it be car or home, that will not be 30 like in the stores.
Click to expand...
Click to collapse
Just search for ADP-H01 on the web. I have seen them as low as $16.
Good suggestion leapinlar, looks like I'm gonna acquire a spare soon.
The NC is a mature product, and anything worth talking about has been talked out. Search these NC forums (or just Google in general) for "nook color charger".
Here's one that's interesting: The OS makes a difference. Those using CM7 can charge using any 2.0 or 2.1A charger, with any cable (presumably of sufficient gauge to carry 2A). Those using stock ROM must use OEM charger & cable.
http://forum.xda-developers.com/showthread.php?t=1002332
I'm not sure about stock, since I converted my NCs OOB. But my experience (using CM7) is same as the OP in above-linked thread. I can charge with any 2A charger and standard cable.
e.mote said:
The NC is a mature product, and anything worth talking about has been talked out. Search these NC forums (or just Google in general) for "nook color charger".
Here's one that's interesting: The OS makes a difference. Those using CM7 can charge using any 2.0 or 2.1A charger, with any cable (presumably of sufficient gauge to carry 2A). Those using stock ROM must use OEM charger & cable.
http://forum.xda-developers.com/showthread.php?t=1002332
I'm not sure about stock, since I converted my NCs OOB. But my experience (using CM7) is same as the OP in above-linked thread. I can charge with any 2A charger and standard cable.
Click to expand...
Click to collapse
Yes, you can charge, but not at the full rate. The charging block must have the two center pins shorted (d+/d-). Some charging blocks have that and some do not. If they are shorted, the nook might allow the block to deliver the full 2+ A rated on the block. But the cable must be able to deliver that much current. Only the stock cable can do that. It has extra pins (a total of 12) in the nook end of the connector to deliver that much. Regular microUSB cables do not have those pins. That is why nook cables have an end that look longer than standard cables. So the charging circuits in the nook sense the shorted data pins and the extra pins in the cable, then it turns on full charging. It does this for all roms. If it does not detect those two conditions, it assumes you are connected to a USB port and limits charging current to 500MA regardless of block capacity.
leapinlar said:
Yes, you can charge, but not at the full rate. The charging block must have the two center pins shorted (d+/d-). Some charging blocks have that and some do not. If they are shorted, the nook might allow the block to deliver the full 2+ A rated on the block. But the cable must be able to deliver that much current. Only the stock cable can do that. It has extra pins (a total of 12) in the nook end of the connector to deliver that much. Regular microUSB cables do not have those pins. That is why nook cables have an end that look longer than standard cables. So the charging circuits in the nook sense the shorted data pins and the extra pins in the cable, then it turns on full charging. It does this for all roms. If it does not detect those two conditions, it assumes you are connected to a USB port and limits charging current to 500MA regardless of block capacity.
Click to expand...
Click to collapse
I have found that as long as I have my charger cable, I can use any "block" to charge. I generally will use my IPAD block and that charges it just as quickly. So instead of having to spend 30 bucks for a new nook block, I can just use my cable and a different block. its very convenient.
IPAD bricks provide 2.0A and the B&N ones are rated at 1.9A. It boils down to the (semi-)proprietary cable.
ufkal said:
I have found that as long as I have my charger cable, I can use any "block" to charge. I generally will use my IPAD block and that charges it just as quickly. So instead of having to spend 30 bucks for a new nook block, I can just use my cable and a different block. its very convenient.
Click to expand...
Click to collapse
iPad chargers also have the data pins shorted.
leapinlar said:
Yes, you can charge, but not at the full rate. The charging block must have the two center pins shorted (d+/d-). Some charging blocks have that and some do not. If they are shorted, the nook might allow the block to deliver the full 2+ A rated on the block. But the cable must be able to deliver that much current. Only the stock cable can do that. It has extra pins (a total of 12) in the nook end of the connector to deliver that much. Regular microUSB cables do not have those pins. That is why nook cables have an end that look longer than standard cables. So the charging circuits in the nook sense the shorted data pins and the extra pins in the cable, then it turns on full charging. It does this for all roms. If it does not detect those two conditions, it assumes you are connected to a USB port and limits charging current to 500MA regardless of block capacity.
Click to expand...
Click to collapse
In my experience there are actually 3 possible max charging rates into the Nook Color
1) USB mode where a charger / cable doesn't have shorted data lines (including PC) - Max 500 ma
2) AC mode (half) where a charger does have shorted data lines but a standard USB cable is used - Max 1000ma
3) AC mode full where a charger has shorted data lines and a Nook proprietary cable is used with the extra power pins - Max 1900ma
>In my experience there are actually 3 possible max charging rates into the Nook Color
How did you measure the differing DC current? Clamp meter? In-line resistor?
Battery Widget in the Play Store will tell you near real time.
Rodney
rhester72 said:
Battery Widget in the Play Store will tell you near real time.
Rodney
Click to expand...
Click to collapse
That's what I have used and it seems to tally well with rate of charge of the battery. It indicates AC or USB charging (shorted / non-shorted data lines) and showed 1000mA in AC mode with standard USB cable as opposed to 1900 with Nook cable.
>Battery Widget in the Play Store will tell you near real time.
Can you provide the developer name? There are many battery widgets, and those I've tried don't indicate charging level. TIA.
e.mote said:
>Battery Widget in the Play Store will tell you near real time.
Can you provide the developer name? There are many battery widgets, and those I've tried don't indicate charging level. TIA.
Click to expand...
Click to collapse
I use Battery Monitor Widget Pro by 3C. It has a history screen that shows charging current vs time. I think they have a free version.
Thanks for the tip. Battery Monitor Widget is a better monitor than those I've tried, although it overloads on detail. However I think the +/- mA reading is a net reading (charge - discharge rate) rather than the charge current by itself. Since the unit needs to be on for the widget to run, it's probably not possible for it to get just the charge reading.
+1 for the battery information widget. I actually like all of the information.
Sent from my Thunderbolt using Tapatalk 2

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] Does the Moto X require a certain amperage to charge?

Sorry if this has been asked before as I wasn't able to find a topic. I've noticed my phone only charges with certain chargers of mine. My car charger refuses to work along with one that I keep at work. The only thing I can think of is that the phone requires a certain amperage to even recognize that it is plugged in. Is this true?
Have you tried different micro usb cables? I think that is more likely to be the problem then the power supply itself.
Steve-x said:
Have you tried different micro usb cables? I think that is more likely to be the problem then the power supply itself.
Click to expand...
Click to collapse
No, but I have used the same cables in a different adapter and it work.
Different chargers have different wiring on the data pins (2&3) depending on the host device. My experience with Android devices is that most (not necessarily all) expect data pins on AC chargers to be shorted, while Apple devices expect to see a load across these pins. A number of Android devices I have had drop their charging rates when that load is encountered just as if it was plugged into a computer's USB port (but can't say for sure whether they all do).
enjoimadcow said:
No, but I have used the same cables in a different adapter and it work.
Click to expand...
Click to collapse
I think that the point is in voltage rather than in current. A lot of cheap adapters charge with the voltage above 5.2 what is approximately the margin where the electronic protection in phone blocks the charger to prevent it from damage. Low current could never be the problem besides the charging circle is prolonged.

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