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I am trying to find the maximum possible current draw of the Nexus 4 when recharging the battery.

  • The adapter that comes with the Nexus, supplies 1.2A
  • The Qi Charging Station needs 1.8A

But I can't find the actual maximum current that can be drawn by the Nexus. I am using a battery pack that supplies around 2A and it only can keep the Nexus running (when playing Ingress), but doesn't really recharge it. I wonder if this is caused by the batteries 2A maximum output or if it's due to the nexus having an upper limit it can handle.

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You might find the current draw in the battery menu, after "dialing" the magic number *#*#4636#*#* (alias *#*#INFO#*#*). –  Izzy Apr 13 '13 at 14:31
    
Nice hint, I didn't knew that. But it sadly doesn't show anything related to the phones or batteries max current specification. –  Baarn Apr 13 '13 at 14:38
    
Nope -- and that's why I didn't put it as answer. Valuable information, though; and up to Froyo that menu even contained wakelock statistics (quite useful to identify apps eating your battery). There are a lot more of those "magic numbers", check here and, for more, here ;) The max current specification you probably won't find on the device itself, but in its specification papers. –  Izzy Apr 13 '13 at 14:43
    
Not the Nexus 4, but the Galaxy Nexus will not draw any more than 900mA (maximum for USB 3.0). I wouldn't be surprised if Google specified the same strict compliance to the USB spec for the Nexus 4. –  Compro01 Apr 15 '13 at 15:09
    
Additionally, Current Widget might be of use. It uses a fairly extensive listing of possible locations where different phones report battery current. That'll at least tell you how much current your getting, which might tell you where the bottleneck is. I can't seem to find any info on if it works fully with the Nexus 4 though. –  Compro01 Apr 15 '13 at 15:38
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2 Answers

android tuner reads around 840ma

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Is this reading reliable, how does android tuner measure the current? –  Baarn Jun 14 '13 at 8:21
    
It seems fairly accurate. I just did the same on my Nexus 4 and got the same reading. I did compare this value to the value when unplugged (a negative value), and it seems to indicate that about 1A is all it draws. –  mlissner Jul 19 '13 at 16:20
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I just measured the current when using the LG charging adapter and it only consumpts 433mA. So there is no benefit using an AC adapter instead of a PC.

EDIT: Cable broken, see my last post.

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Was that adapter a dedicated one for that device? The cable used belonging to it? For "fast charging", it might be the addional 5th contact is used to signal the power source (i.e. tell the device it's connected with a "fast charging" source). Charging adapter and cable might need to support that. See this answer for "pin details". –  Izzy Apr 17 '13 at 12:03
    
Hi, it is the AC charging adapter which was delivered with my nexus 4 (model : MCS-01ET) –  MasterFX Apr 17 '13 at 13:29
    
How did you measure the current? –  Baarn Apr 17 '13 at 14:10
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Hi, I just measured again and it seems like my USB Cable is broken (or the Data-Lines). I just used an other cable and now the Nexus goes up to 1A with LG Charging Adapter and Nexus 7/Asus charging adapter (which can go up to 2A). The only way for the Nexus 4 to detect if it is high current or not are the D+ and D- since on the opposite site of the cable is only a standard USB A Connector with 4 Pins (so the ID Pin of the micro B end could not be controlled by the charging adapter). I think there are resistors on D+ and D- which indicates the high current ability of the charging adapter. –  MasterFX Apr 17 '13 at 14:56
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@MasterFX - Yes, there is supposed to be a 200 ohm resistance between D+ and D- on a dedicated charger, per the USB Battery Charging spec. They call it "Dedicated Charging Port resistance across D+/-" and is on page 35 of the spec. –  Compro01 Apr 17 '13 at 16:10
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