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Charging Tytn II with alternative USB Wall Charger

Can the Tytn II be charged with other USB wall chargers other than what comes with the package? I have 4 alternative wall chargers:
(1) USB wall charger for Blackberry 8707g
(2) TravelPac world travel adapter with USB charger
(3) USB wall charger for Aliph Jawbone
(4) USB wall charger for O2 Atom Life
I do charge the Tytn II through USB cable connected to my PC. However, I was reading somewhere that this is ill advised, as from a device longevity perspective it is always better to charge using AC Adaptor chargers as opposed charging through the PC, not sure how true it is. I do see under the “Power” settings that there is an option to turn “When device is turned on, do not charge the battery when connected to the PC”, so maybe there is some truth to it.
In any case, my biggest concern is with the wall charger for my Blackberry. The Blackberry seems to be using somewhat different voltage from other USB chargers as I am not able to charge the Blackberry with any other charger other than its own wall charger or through the PC. For example, charging the Blackberry through the TravelPac adaptor more often than not does not work.
Question is, can I (safely) charge my Tytn II with other USB wall chargers? Any downside from using non-HTC chargers? Thanks

Unless someone has already tried one of those other chargers and can post their success here, I would not try it - there have been reports of generic car-chargers and the like frying circuitry on the Kaiser, as the USB power connection is wired differently to some (superficially similar) devices. It's not really worth risking it, when I'm sure you can pick up a spare HTC charger for not much.
I charge from USB everyday at the office (and the mains, when I'm away from work for more than a couple of days) and after three months my battery performance seems much the same as everyone else reports - in fact, better than some. I know opinions differ on whether these modern batteries have any kind of "memory effect" or benefit from a proper discharge cycle etc - personally I've seen no evidence of that. In any case, absolute worst case scenario is buying a new battery some way down the line - given that there are already higher capacity aftermarket versions of the stock battery on sale, that might not even be a bad thing.
With my old Sony Ericsson M600i I used to find that USB charging would never bring the phone to full charge (however long I left it), and the 90-odd % charge it did have would never last quite as long as a proper mains charge. No sign of either issue on the Kaiser.

As long as the charger in question is rated at no more than 5v/1A (as the original Kaiser charger) it should be safe. The Kaiser can probably take more than 1A safely tho, but I won't guarantee that. That said, most wall-chargers are rated somewhere around 5v/1A.

USB charging in car?

Iam using the Dell Streak 7 as a sat nav system in the car. Ive tried to charge it up on the usb car adapter but it seems to loose its charge over time, making the D7 unusable for the purpose of a sat nav. Am i doing something wrong or is there a special usb car adapter for the job?
Thanks, David.

Does it say it's charging when plugged in?
Depending on how powerful your charger is it's likely that it's draining faster then the charger can provide. At best on my s5 it's just barely faster then the charger and the s7 needs more power then that.

Thanks for peply, yes it states it is plugged in. I came to the same conclusion. Wonder if there are any other chargers that have more juice.

diddy64 said:
Thanks for peply, yes it states it is plugged in. I came to the same conclusion. Wonder if there are any other chargers that have more juice.
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Click to collapse
There are several that will do the job. Just look for specs that include putting out 5.5 volts and 2 amps. Several of the chargers that are made for the iPad2 will work. And you may want to install a lighter adapter that you can wire directly to the battery that will allow up to 2 or 3 amps from each port

Most standard USB ports do not put out enough power to charge the DS7. The best bet is to use a inverter that plugs into your cigarette lighter and then plug the charger into that, not just the USB cable.
http://www.amazon.com/Power-Inverter-Charger-Portable-SmartPhones/dp/B00144KS6W

I use this setup:
Bestek Adapter
Trans4m lighter adapter
The Bestek I have wired to the battery so I have no fuse problems with lighter, and with that I can charge either my iPad2 or my Streak7, IF I need to charge both, then I plug the Transform adapter into the Bestek and can then charge BOTH devices, the Ipad2 AND the Streak7 and a couple of other things if need be

Thank you guys, this gives me alot of hope. Once again you all get my thanks.
Cheers,
David.

Yea, like they previously stated not all chargers are created equal.
Unless it states it's a tablet/ipad charger you cant assume it's doing 2+ amps. Most phone/lower end ones can only do 500mA/1A.
Realistically you'd prob need at least 2 amps to get a net gain while using gps/anything demanding. But I dont know if it would even try and draw above that if given the chance. [email protected] is what the bundled wall charger does and can accept up to 5.5v (as it's still within the +/-10% tolerence of the usb spec, but just barely)

My fully charged stock S7 WiFi running 514 draws only 45-70mA. Maybe starting fully charged would help?

wptski said:
My fully charged stock S7 WiFi running 514 draws only 45-70mA. Maybe starting fully charged would help?
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Click to collapse
I don't know anything about how it works, but I imagine tablets are wired to know when they are receiving the correct amount of input. For instance, if you connect your Streak 7 to a powered USB hub that only puts out 5 volts, it won't charge nor will it charge when connect via usb to the PC, it has to be receiving 5.5 volts and 2 amps before it will let itself receive charge. I have an iPad that is the same way and have noticed all the tablets I have had my hands on are the same, Galaxy Tabs, Transformers, Xoom... all those have to receive higher numbers to charge. So you have to have a cigarrette lighter adapter that puts that out, if it's for a cell phone it won't do anything for it

cdzo72 said:
I don't know anything about how it works, but I imagine tablets are wired to know when they are receiving the correct amount of input. For instance, if you connect your Streak 7 to a powered USB hub that only puts out 5 volts, it won't charge nor will it charge when connect via usb to the PC, it has to be receiving 5.5 volts and 2 amps before it will let itself receive charge. I have an iPad that is the same way and have noticed all the tablets I have had my hands on are the same, Galaxy Tabs, Transformers, Xoom... all those have to receive higher numbers to charge. So you have to have a cigarrette lighter adapter that puts that out, if it's for a cell phone it won't do anything for it
Click to expand...
Click to collapse
The voltage is constant but current isn't. It won't know how much current is available unless it asks for it. It's like a 2A fuse, you can draw up to 2A, no more.
Even with a fully charged battery it'll show charging at 98% for a short time and that's when I saw the higher 70mA but I'm not sure if it's in the CC or CV part of a Li-Ion charge cycle but I'd guess CV because it's less than 100mA.

My bad thinking measuring AC input current instead of DC current since this thread is about USB power.
Used a cheap ReTrak USB extension cord that loses connections to seperate the wire to measure DC current. My fully charged S7 showing 100% charge still draws 150mA after hours of being plugged in. Since Li-Ion cells normally don't use a constant trickle charge, I "assume" something draws on the battery all the time along with the indicator light and buttons.
Booting up it draws a little over 1A, fully charged while booted up, it draws around 600mA. While charging and powered up, it draws 914mA. Charging while off, it draws 1160mA. Far from 2A.

wptski said:
My bad thinking measuring AC input current instead of DC current since this thread is about USB power.
Used a cheap ReTrak USB extension cord that loses connections to seperate the wire to measure DC current. My fully charged S7 showing 100% charge still draws 150mA after hours of being plugged in. Since Li-Ion cells normally don't use a constant trickle charge, I "assume" something draws on the battery all the time along with the indicator light and buttons.
Booting up it draws a little over 1A, fully charged while booted up, it draws around 600mA. While charging and powered up, it draws 914mA. Charging while off, it draws 1160mA. Far from 2A.
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I understand that, but you are missing the point, if the internal wiring of these tablets don't receive the 2A they want they WILL NOT even begin to charge. I tried literally dozens of chargers when I first got my S7, spent a couple hundred bucks actually, and none of the chargers not meant for larger devices won't work, and what those chargers all had in common, 2A output

The S7 can and will draw off low capacity ports, it just wont admit to charging unless it's at least 1A as it's just that.
I've had my S7 charge off a 500mA port on my pc at the rate of like 1%/hour while sleeping. As it's barely gaining even while idleing it's not really charging in the literal sense, but it's definitely charging in the technical sense.
Are your data lines shorted together? I believe most high draw devices wont attempt to pull 2A unless it detects that it's on a high draw charger (which I think do this to indicate it as such)

cdzo72 said:
I understand that, but you are missing the point, if the internal wiring of these tablets don't receive the 2A they want they WILL NOT even begin to charge. I tried literally dozens of chargers when I first got my S7, spent a couple hundred bucks actually, and none of the chargers not meant for larger devices won't work, and what those chargers all had in common, 2A output
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Click to collapse
I don't know why your various chargers didn't work but it doesn't seem to be because of current. It didn't charge at 2A or even close to that.
If what your saying correct, why was I able to charge at less than 2A then? Could this be a ROM issue? I only had Froyo for a few hours but I've read that it didn't support USB charging which came with HC but it only charges with the S7 OFF.
It's possible that the demand went higher and I just didn't see on my current clamp meter. I'll have to try a current clamp and a scope to see if I missed a peak level.
Also what we are refering to as the charger might not be a charger but only a power supply and the actual charging circuit is in the S7.
I did notice one odd thing though. The green LED lights up at around 90% battery level and it's still charging. I downloaded a battery app which read the same level.

wptski said:
I don't know why your various chargers didn't work but it doesn't seem to be because of current. It didn't charge at 2A or even close to that.
If what your saying correct, why was I able to charge at less than 2A then? Could this be a ROM issue? I only had Froyo for a few hours but I've read that it didn't support USB charging which came with HC but it only charges with the S7 OFF.
It's possible that the demand went higher and I just didn't see on my current clamp meter. I'll have to try a current clamp and a scope to see if I missed a peak level.
Also what we are refering to as the charger might not be a charger but only a power supply and the actual charging circuit is in the S7.
I did notice one odd thing though. The green LED lights up at around 90% battery level and it's still charging. I downloaded a battery app which read the same level.
Click to expand...
Click to collapse
You were able to charge because your charger was CAPABLE of outputting 2A at least... try charging with one that CAN'T put that out and you should find that the Streak will not charge, on ANY ROM has been my experience, custom or stock

cdzo72 said:
You were able to charge because your charger was CAPABLE of outputting 2A at least... try charging with one that CAN'T put that out and you should find that the Streak will not charge, on ANY ROM has been my experience, custom or stock
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Click to collapse
Capable is the magic word here. The wall wart isn't putting out 2A from what I've seen, unless it does for a split second at the start which I'm going to look into.
Most wall warts at whatever their rating is put out a higher voltage with no load and slightly higher than its marked voltage under a load. If it required [email protected] max., you used a [email protected], S7 needs more current, the voltage would decrease. What's been stated here might be that the voltage was being pulled down and that's why the S7 wouldn't charge, not "really" the 2A issue.
I have a battery pack/cell load testing device used on RC stuff that connects via USB port for its graphic software. There were issues with certain Dell laptops that had a low voltage at their USB ports.

Maybe starting fully charged would help?
I have the OEM T-Mobile car charger and I've found that if I have a full charge before plugging the Streak into the charger it maintains a full charge for as long as I'm driving/using it. Otherwise, with a less than full charge I've watched it slowly discharge even though it's plugged in and is charging.
FYI: I also have a top of the line car charger for an iPad2 that charges the iPad no matter what charge level I plug it in. This iPad charger has a USB port which I have plugged the Streak USB cord into and it also doesn't keep up with the Streak's discharge if the Streak isn't a full charge to begin with. Kind of strange because I would think the iPad would draw more than a Streak. (the iPad isn't plugged in at the same time the Streak is charging)

DCoop said:
Maybe starting fully charged would help?
I have the OEM T-Mobile car charger and I've found that if I have a full charge before plugging the Streak into the charger it maintains a full charge for as long as I'm driving/using it. Otherwise, with a less than full charge I've watched it slowly discharge even though it's plugged in and is charging.
FYI: I also have a top of the line car charger for an iPad2 that charges the iPad no matter what charge level I plug it in. This iPad charger has a USB port which I have plugged the Streak USB cord into and it also doesn't keep up with the Streak's discharge if the Streak isn't a full charge to begin with. Kind of strange because I would think the iPad would draw more than a Streak. (the iPad isn't plugged in at the same time the Streak is charging)
Click to expand...
Click to collapse
The S7 must run some check before it tries to charge . Whatever it is the OEM supplied power supply passes the test.
What's the specs on your two power supplies?

Just remember if you dont have the same 2A for charging in the car. You cannot charge the streak while its TURNED ON. Same with USB charging, just turn the streak OFF, then charge. It will work. =)
Otherwise, Id get a DC to AC converter for the car, plug in your normal adapter.

Make non-motorola charger work?

So this is my first motorola and I had heard of the issues they have with non motorola chargers. Now I am experiencing it first hand. With the same ac charger I have charged many phones with and is capable of 1 amp output (D4 charger is only rated at 850 mA) my D4 struggles. With the device off it charged painfully slowly. While on it cannot even charge. It discharges while plugged in despite the charging indicator and reporting "charging (AC)" in status.
How does it know it is not a moto charger? Is it just about the resistance between the data pins? For most other phones shorting the data pins on the charger indicates to the phone that it is a high current charger and not a computer USB port. Is there a similar trick for motorola phones? I would rather not have to purchase an overpriced moto oem car charger. I have a perfectly fine 1.2 amp car charger soldered directly into my car's 12v system behind the dash. Can I make it work?
Thanks!

On a regular basis I successfully charge my D4 using both a charger from a Samsung Reality feature phone and from a B&N Nook Simple Touch, in addition to the one that came with it. I've also used a variety of car chargers.
Sent from my DROID4 using XDA

Actually, so far I have only one charger that had any trouble charging the phone (it was a $3 charger with 2 USB ports), but the $3 charger with ONE USB port works fine, as does the Nook Color charger, Blackberry charger, and Samsung charger I have tried it with, as well as both my old car charger and Lenovo's always-on charging port on their laptops.

JKingDev said:
So this is my first motorola and I had heard of the issues they have with non motorola chargers. Now I am experiencing it first hand. With the same ac charger I have charged many phones with and is capable of 1 amp output (D4 charger is only rated at 850 mA) my D4 struggles. With the device off it charged painfully slowly. While on it cannot even charge. It discharges while plugged in despite the charging indicator and reporting "charging (AC)" in status.
How does it know it is not a moto charger? Is it just about the resistance between the data pins? For most other phones shorting the data pins on the charger indicates to the phone that it is a high current charger and not a computer USB port. Is there a similar trick for motorola phones? I would rather not have to purchase an overpriced moto oem car charger. I have a perfectly fine 1.2 amp car charger soldered directly into my car's 12v system behind the dash. Can I make it work?
Thanks!
Click to expand...
Click to collapse
Not sure how it knows one way or the other. I've successfully used a few LG chargers to charge my D4. The only really hickup I've ran into is the usb cables from those lg chargers won't sync data to the phones when plugged into a computer, they'll still charge off the usb port but won't read as a usb connection to the computer.

Heh, captcha is trynply.
Every charger I've used, including an old charger for an EN-V, kindle, supplied, and various other phone chargers works just fine with this phone. Probably have a bad charger, guy.

Thanks for the replies. I guess I was wrong. My modded car charger works just fine. I guess its just time to retire the old charger that I have been using. I think it might be my old nexus one charger.

A more important question would be does the thing charge over computer-bound USB ports?
When you're without a charger, but there's a USB cable that fits your phone, sometimes a regular USB data port is the only that is around... even though it might take a really long time.
Try a computer bound USB port, then try your actual charger, again. Or do the hard reset (vol down plus power, hold until it actually does it), which is just like pulling the battery.
See how that goes.
Chris

RueTheDayTrebek said:
A more important question would be does the thing charge over computer-bound USB ports?
When you're without a charger, but there's a USB cable that fits your phone, sometimes a regular USB data port is the only that is around... even though it might take a really long time.
Try a computer bound USB port, then try your actual charger, again. Or do the hard reset (vol down plus power, hold until it actually does it), which is just like pulling the battery.
See how that goes.
Chris
Click to expand...
Click to collapse
It does in fact charge via USB port. In fact, it has a 'charge only' mode. Depending on how much juice your port puts out, and what you are doing with the phone, it will charge slowly/not at all, though.

from my experiences, the droid 4 will not accept lg microusb cables, the charging bricks work tho. i use a blackberry microusb on mine along with a Logitech and the stock moto ones. 1.2 amps is a bit high but not crazy sounding. personally, I charge at 1 amp.

alternate source of fast charger?

So I left my NC wall charger and cable in my hotel room in South Korea last weekend, and of course I am back home in TX with no way to charge besides normal microUSB, which takes forever.
Is there any source other than B&N for a high-speed (high current) charger and cable? The B&N one is like $25, which is not too bad, but I still would rather find an alternative if possible.

What you're looking for on the charger is something that's rated at 1.9A or better. Most made for the ipad are 2A. The only alternative I've made use of is a Belkin one they sell at Wallyworld for $20 bucks, (same type deal as you but I still had the cable and was still on the road). With the stock cable I get a full charge in about three hours and with a regular cable I get a full charge overnight. If I had to do it over I might have pushed my schedule a little harder and looked for a B&N so I would have ended up with a "spare" cable out of the deal.

mr72 said:
So I left my NC wall charger and cable in my hotel room in South Korea last weekend, and of course I am back home in TX with no way to charge besides normal microUSB, which takes forever.
Is there any source other than B&N for a high-speed (high current) charger and cable? The B&N one is like $25, which is not too bad, but I still would rather find an alternative if possible.
Click to expand...
Click to collapse
Bummer! I travel to S. Korea regularly in Jan/Feb and in early Aug. Team development programs with Samsung at their Cheonan S1 Training Center. Where do you travel to in S. Korea?

Where as finding an adequate charger seems easy enough, its the cable that's the problem. Has to be an official B&N cable for fast charging. A standard microUSB will charge very slowly. I've yet to find an aftermarket equivalent.

Has anyone checked out a touchpad charger? It looks like it's just a standard micro usb charge that puts out 2A. It seemed to charge my nook reasonably fast but I didn't let it get above 95% since I wasn't sure if it would hurt the battery. I'll have to do a better test to see how long it takes to charge

bitnerd said:
Has anyone checked out a touchpad charger? It looks like it's just a standard micro usb charge that puts out 2A. It seemed to charge my nook reasonably fast but I didn't let it get above 95% since I wasn't sure if it would hurt the battery. I'll have to do a better test to see how long it takes to charge
Click to expand...
Click to collapse
Here are the results of a very quick test that I just performed:
Nook Color running Mirage CM7 latest version (5/18)
Overclocked to 1100Mhz and interactiveX governer
Screen at 100% brightness
Battery Monitor Widget main graph screen displayed entire time
Logging set for every 60 seconds
Test lasted about 5min for each combination
Battery at about 70%
Nook charger & cable
- average reading of +892mA
- mV increased 3844mV to 4053mV
Touchpad cable & charger
- average reading of -335mA
- mV increased 3847mV to 3901mV
Touchpad cable & Nook charger
- average reading of -407mA
- mV increased 3847mV to 3888mV
Nook cable & Touchpad charger
- average reading of +1211mA
- mV increased 3826mV to 4081mV
So it looks like the Nook cable is the key. As long as you have a charger that puts out around 2 amps or so and the Nook cable, the Nook will fast charge. It actually charged faster on the HP charger (2.0A output vs 1.9A for the Nook charger).
I also tried a cheap data cable I had and it stated "USB charging" and the results were similar to using the HP cable but a bit lower on the mA readings.
I plan to run the test again using a high Amp car charger but I think the results will be pretty much the same.
The best combination for a super fast charge is the HP Touchpad wall charger and the Nook cable

Just call B&N, talk nice. They will either give you a new set, or set you up with an order. They gave one to me, 2 day ship too...

My cable broke last weekend. I went to a BN store, and they sell the cable without the charger for $15.
Sent from my NookColor using Tapatalk 2

I don't know about the fast charger, but the charger for a samsung cell phone (not a smart phone just a normal phone) phone will charge the nook. I've accidentally plugged it in and it worked. I've not used it for extended periods so can't speak to its long term ability to work.

joelgrice said:
[...] So it looks like the Nook cable is the key. As long as you have a charger that puts out around 2 amps or so and the Nook cable, the Nook will fast charge. It actually charged faster on the HP charger (2.0A output vs 1.9A for the Nook charger).
Click to expand...
Click to collapse
I've noticed that my NT on B&N firmware 1.4 will charge on a non-B&N charger, but that the charging status shown in settings always says "not charging". My NC on CM7.2 simply indicates it's charging. I don't know if the B&N status really matters or not, but it is finicky about the wall adapter. If/when you re-test, could you please note the battery status?
Meanwhile, I did some testing with a PowerGen 12v adapter. I was able to get the NT showing "charging (AC)" while using the 1A plug on the adapter with the B&N cable. Reading the little booklet that comes with it indicates that "some devices" can pull more than 1A off this plug, including the "HP touchpad, Kindle Fire". While charging, I did get the erratic screen issue while plugged in. With the B&N charger, the same cable didn't cause this behavior on the NT. Not sure what that means, but you basically can't use it while it charges with the adapter. The 2A plug, described as "for the iPad" shows "not charging" (but not discharging). Using a generic microUSB cable also yields "not charging".
I also tested a EZOPower 7800 mAh supplemental battery. I was able to get a NT showing "charging (AC)" while using the "S" plug, described as compatible with the Samsung P1000 (Galaxy Tab) with the B&N cable. The "I" (iPad) plug did not work. The battery itself does charge off any 1A USB source, and will charge external devices at full 2.1A power as it charges. This means you should be able to let this battery power your NC, while the EZOPower battery charges more slowly from a normal 1A USB 12 VDC or AC adapter. Once the NT is fully charged at full rate, the EZOPower battery will itself charge. There were no screen issues with this combination, and I could use the device as it charged (with the usual cautions about the fragile B&N cable, of course.)
I don't know if the distinction between "not charging" and "charging (AC)" actually means anything, but the B&N firmware seems to care, while CM doesn't.

The reason why people notice they need a stock NC cable to 'fast charge' is that While it appears at first glance to be a standard microUSB plug.... it is not. Go ahead, try and plug it into your cell phone (no, it wont hurt your phone). The NC 'microUSB' plug actually has many more pins than the standard 5 (Something up near 20 as I recall). There are the normal 5 upfront, then the rest as further back. When you plug it in to charge, one of the rear pins connects and can supply the 1.9A max charge current. That 1.9A pin is directly connected to the Power Mgmt chip and is the only way to get high current charge.

The <explicitvie delted) whole story
There are three pieces to this puzzle.
1) a high power 2amp / 2000ma USB charger
2) shorting the correct pins in the cable to let the device know it is connected to a high power charger
3) extra long 12 ping next gen micro usb cable.
Some details...
Not all 1.9 / 2amp chargers are actually 2 amps
Some are 2 x 1amp
Some are mis-represented
etc.
I have tried many...
Some are frauds
Some are designed by idiots.
Few actually work
Yes, this is a Ipad spec.
Shorting the data pins (2 to 3) is required.
Go on eBay and look up pwr+ usb filter.
This little USB type a male to female adapter
does just that
shorts the data pins
finally the cable...
There is a new type of micro USB 12 pin connector on the cable.
The other big side is standard 4 pin.
The micro connector is longer than a standard micro USB.
The are some overseas import cables that work.
A standard USB cable WILL NOT WORK.
PS:
using a standard charger and cable will work but takes 4x longer.
Charging while on will run the battery down.
Pretty much stay with genuine OEM parts.
Especially the cable.
Unless you are tech savvy.
Google 12 pin USB
You can source a good 2amp power supply.
You can use OEM Ipad chargers.
HP makes a good 2A charger. PN 157-10157
12V - Scosche big black 4" long job 2 port 2.1a + 1a
However you must short the data pins with the pwr+!
mail at lofthouse dot org

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.