Database Develop

Alternative 5V chargers (currency?)

Hi, I'm really a noob when it comes to electronics. For all I know, when a cable fits it should work
I have a couple of microUSB chargers laying around. They all have an output of 5 Volt but they output a currency that differs from the standard charger (1A).
What is the "golden rule" wrt currency? Are chargers with a currency that is less than 1A save?

current is not pushed, it is pulled by your device as necessary. voltage is pushed, so correct voltage,5V in this case, is very important. As for the current, if the charger can't supply enough current with that voltage it will get hot and cause problems. i.e., you should have a current greater or equal to your original charger and same voltage. this applies to ALL of your electronics.

ozkaya said:
current is not pushed, it is pulled by your device as necessary. voltage is pushed, so correct voltage,5V in this case, is very important. As for the current, if the charger can't supply enough current with that voltage it will get hot and cause problems. i.e., you should have a current greater or equal to your original charger and same voltage. this applies to ALL of your electronics.
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Thank you very much for this explanation. What do you think, a 5v charger with a current of 850mA will that cause big problems when I use it just accidentally to charge my device.

appelflap said:
Thank you very much for this explanation. What do you think, a 5v charger with a current of 850mA will that cause big problems when I use it just accidentally to charge my device.
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Click to collapse
It probably wouldn't be a lot of problems, if you really have to do it, charge it when the screen is turned off, so that you will need less current.

You can charge without risk with any USB charger. Unless the charger "signals" that it can supply more than 500mA by having the 2 USB data pins shorted, the HD2 won't pull more than 500mA, which is the minimum a USB charger must be able to supply.

"Golden rule" - If You have 5V its safe for Your phone, current level is determining the time that You need to charge battery.
Kilrah sad that HD2 'pull' no more than 500 mA - ok, if this is true ( i believe it is , he always make some test for it ) original charger needs about 2h, with 250 mA charger it will take more than twice of that time - 4h ( it's not fully linear )
@Kilrah - did You test what's power ( current taken ) consumption during charging ? it's really only 500 mA ? if so, than why HTC use 1A charger ? usually safety rules are about 15 - 30% more than max current needed.
0.5 A + 30% = 0.65A , so why 1A ?

The minimum current what HD2 accepts is 500mA because this is the USB standart.
If the supply could deliver more than 500mA the HD2 will take it up to 1000mA. The maximum current which the HD2 can use is 1A (1000mA).
So if your charger can deliver 5V and 2000mA the HD2 will limit the current to 1000mA. So you can use a charger, when the voltage is 5V and the current at least 500mA.
The push pull principe in the post before is correct, because the charger is a voltage source and not a current source.

I am already enjoying the benefits of proposed standardisation of phone chargers to micro usb pin. Since I upgraded with HD2 from Nokia N97 I am using the nokia wall chargers as well as well as car charger. I didnt have to buy new charging accessories for this mighty HD2.
By the way would the Nokia data cables (micro usb) be able to sync data when used with HD2. Havent tried yet.....

afropolak said:
@Kilrah - did You test what's power ( current taken ) consumption during charging ? it's really only 500 mA ? if so, than why HTC use 1A charger ?
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As said, IF the 2 USB data pins are NOT shorted (that's how it is by default on <500mA/3rd party chargers, or on a PC), the HD2 will limit the current it pulls to ~450mA.
IF they are shorted (on chargers that support higher current like the supplied one) the HD2 will pull more. With the supplied charger it's about 850mA, with a 3rd party "800mA" Chinese charger that didn't have the pins shorted but was modded to have it done, it pulls about 650mA.
PlayStation said:
By the way would the Nokia data cables (micro usb) be able to sync data when used with HD2. Havent tried yet.....
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Micro USB is a standard, so every micro USB cable should be the same. If not, you've got a botched knockoff.

so how do you short the cable assuming I get a car charger without a USB to micro USB cable and sourced my own cable from a parts bin that was probably for computer usage?

cheahcl said:
so how do you short the cable assuming I get a car charger without a USB to micro USB cable and sourced my own cable from a parts bin that was probably for computer usage?
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I don't think that would be a good move!
You would have to be certain of the regulation circuitry of the charger and it's ability to cope with the attendant initial draw of the battery when plugged in.
This will depend on the state of drain of the battery and the various functions in operation at the time on the phone.
At the moment of plugging in is when the draw will be highest and when any protection circuitry will be essential.
A well topped up battery will "draw" less than a depleted one and will continue charging on as little as 350mAh (again depending on what is running on the phone).
A very depleted battery may well not even start the charging process at such a level. That's why the HD2 comes with a 1000mAh wall charger!
The levels quoted for PC/Laptop USB power are nominal off load levels and will vary depending on any othe devices plugged in on the same bus supply.
So, with a PC that has a few attached USB devices, you may well NOT see 500mAh and as has been reported before, you can get battery depletion back into the USB port as other devices draw from the phone!
Always best to keep the battery topped up to prevent "charging strain" on the cells. This will maximise the capacity available when you need it for those longer periods of time.

Anyway to charge at ~2 amps from computer?

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.
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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
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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.
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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
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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

Do you use your nook color charger on your phone?

I'm just curious. I'm not sure it's safe, since one has a 10W output, and one has a 5W. If you do, have you had any problems? Notice it charging faster than usual?

deleted +10

Yeah, that's what my phone charger outputs. The iPad/iPhone chargers have the same output as the Nook/Android phone, and they claim to be safe to use with either one. Not sure if that applies to android phones though, or if there needs to be some safety circuit in either the phone or the charger. Would love to only have to deal with one charger...

It's 5 volts at UPTO 2 Amps. If your device can only draw 5W thats all it will do then overcharge protecton etc cuts in.
I've used the Nook charger on
Nook Color
Nexus One
Blackberry
Plantronics SteroeBluetooth headset
No problems.

As long as the voltage is correct you are good to go. The phone draws amps from it, it won't draw more amperage than it needs.

I noticed that my nook USB cord doesn't fit my Motorola Droid 1, however, my Motorola Droid 1 Phone charger fits my nook :\
Anyone else confirm this?
Also, when plugging in the nook I get no indication that it is actually charging, is this suppose to happen?
EDIT: It appears that it doesn't charge when I plug it into my computer, if it is, it is super slow and doesn't display that it is charging. However, when I plug it into the wall with an A/C USB adapter it shows the charging icon.

from what I got, The nook charger has 6 more pins making it faster, but not compatible with other devices, but the nook itself can get a normal charger and it will be fine just slower.

fingerman12 said:
from what I got, The nook charger has 6 more pins making it faster, but not compatible with other devices, but the nook itself can get a normal charger and it will be fine just slower.
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Except the 6 pins (or w/e num) are added on top of the existing ones, so unlike say a headphone jack with an extra layer for using a microphone, its not backwards compatible (atleast not without an adapter) for normal ones (like my headphones example), rather troublesome imo.
But the power converter works fine for phones.
Sent from my MB300 using Tapatalk

knatcal said:
As long as the voltage is correct you are good to go. The phone draws amps from it, it won't draw more amperage than it needs.
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Thanks makes sense.
Just tried it and it works fine on my phone too. Has to use a generic micro usb cable though. The nook one did not work.

I wonder if the reason the nook color cable doesn't work with other devices is due to the charging light built into the cable. I'll try charging it from a non-nook cable to see. If it charges fine either way, I'll be able to cut it down to 1 charger 1 cable. Would be far more convenient.
Has anyone else noticed a slower charge on non-nook cables? If it really does have more pins, that would be a dissapointment. The cable is so short, I'd probably have replaced it anyway.

the nook color charger connector is shaped slightly different -- its longer --, so it wont fit properly into other devices that use standard microusb.

Is there supposed to be some kind of notification when the unit is off, that it is charging properly. I bought my nook color used and it didn't come with its official charger. I have a bunch of standard (low amperage) USB chargers and 1 iPad type (2amp) charger. I tried the iPad one and the unit gave a "Not charging" message in the settings screen.
How long does it take to charge when using a 3rd party charger?

JDMpire said:
Is there supposed to be some kind of notification when the unit is off, that it is charging properly. I bought my nook color used and it didn't come with its official charger. I have a bunch of standard (low amperage) USB chargers and 1 iPad type (2amp) charger. I tried the iPad one and the unit gave a "Not charging" message in the settings screen.
How long does it take to charge when using a 3rd party charger?
Click to expand...
Click to collapse
Do not resurrect dead threads, they will turn into zombies and eat your brains.
How long does a non-BN charger AND Cable take? Four times longer. It's .5A vs 1.9A. You can get by with a 2A charger, but you must have the B&N cable to charge at the 1.9A rate.

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
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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.
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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.