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General 1A or 2A car charger

Discussion in 'Android Devices' started by sam007, Feb 15, 2012.

  1. sam007

    sam007 Well-Known Member
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  2. Jedi54

    Jedi54 Well-Known Member
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    I'd go with the 1amp it was designed for.
    the phone should control the charge so doubt you'll get the full benefit of 2A.
     
  3. Sandroidfan

    Sandroidfan Android Expert
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    I also wonder if it's ok to use 2A output for charging Nexus. I got Anker external battery pack. It's got two charging output ports 0.5A and 2A, and I only use 0.5A to charge nexus. I'm just afraid 2A might damage the phone.
     
  4. Herman76

    Herman76 Lurker
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    You can have a tchernobyl powered charger and your phone still won't do more then 1amp. Or even 0.5 amps if the charger you are using registers as usb.
     
  5. sam007

    sam007 Well-Known Member
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    How does one recognize whether a phone sees the charger as a USB connected device? Is it when it shows the USB debugging options, etc?
     
  6. Sailing_Nut

    Sailing_Nut Well-Known Member
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    When you go into Settings -> Battery with the charger connected, you will see xx% - Charging (yyy)

    yyy will be either USB or AC depending on how the charger is recognized.

    It is VERY important that you find out if the charger is an Android compatible high current (> 0.5A) charger. If not no matter how much current the charger is capable of delivering the phone will ONLY draw 0.5A. (This is because it will be recognized as USB and will obey the USP specification and not draw more than 0.5A to charge)

    FYI an Android compatible charger has the two data pins of the USB connector shorted (connected) together. This is how it recognizes a charger from a USB port. (Obviously a USB port could never have it's data pins shorted together)
     
  7. sam007

    sam007 Well-Known Member
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  8. Sailing_Nut

    Sailing_Nut Well-Known Member
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    If you have connected the phone to the charger and it shows AC then you are good to go.

    The only thing that could bite you with the cable is if one or both of the data wires are broken, but not highly likley because the power and ground would also likley be broken as well.
     
  9. ANewDay

    ANewDay Well-Known Member
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    Just get a Motorola car charger from Aamzon, rated at 950mah, only costs $5 and change.
     
  10. Jedi54

    Jedi54 Well-Known Member
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    sam: let us know if your phone reads it as AC.
    I bought two 1.0 chargers recently and when I checked, they are only registering as USB. :(
     
  11. BrainIs404

    BrainIs404 Newbie
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    I recently did some homework on this same topic and can provide you with a little amplifying info. What you're looking for is a charger that provides a "dedicated charging port" which is currently defined in the Battery Charging Specification Rev 1.2 found here: http://www.usb.org/developers/devclass_docs/BCv1.2_011912.zip.

    There are two important items to look for: rated output of the charger (e.g. 5V / 1.0A) AND that the data pins (D+ and D-) have a MAXIMUM resistance of 200ohms (RDCHG_DAT) between them. Note that a dead short is perfectly acceptable.

    However, most of the adapters I looked at don't provide this kind of information in the specs on retailers' websites. In a lot of cases you will have to resort to reading reviews to find out whether the charger will give you the full rated power. I can tell you from experience that this charger I recently bought does show up as an AC source when charging my gnex: 1000mA Car Cigarette Powered USB Adapter/Charger (DC 12V/24V) - Free Shipping - DealExtreme. It did take a couple weeks for it to make it overseas.
     
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  12. sam007

    sam007 Well-Known Member
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    some great research - thank you!
    problem with that product though is it's a single port. I bought a dual port and will test and post here

    Thx again!
     
  13. kylebarendrick

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    I have the Griffin 2 port charger. It definitely shows up as "USB". I'm assuming that the 1 Amp rating they claim is actually .5 Amps for each port. I am considering trying to modify it to short the data pins.
     
  14. speede541

    speede541 Android Enthusiast
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    No, it's 1A for each port on the Griffin. It shows up as USB because it, nor the cable being used, contain the necessary short or resistor to tell the phone to charge at the higher rate.

    So it's the phone that's "deciding" to charge at the lower USB rate, so as not to exceed the .5A that a USB 1.x device is rated at (such as your PC's USB port).
     
  15. WoodrowB

    WoodrowB Member
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    I bought this several months ago and have been very pleased.

    [​IMG]

    [​IMG]

    Dual USB Charger | Bracketron

    The odd thing is, though, that my GN shows "USB" if I use the green slot identified as "2.1A",

    ...but...

    If I use the "1 A" slot, my charging window shows "AC", and it definitely is charging faster.
     
  16. Crashumbc

    Crashumbc Android Expert
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    B'more

    To clear things up the about the griffin, ONE of the ports SHOWS A/C the other shows USB. ( I have one)

    I think this has to do with how "dual" port chargers are wired (see post above about the other dual port charger)


    FYI, the USB spec is what determines which your phone charges at. if the middle two pins (normally the data pins) are below a certain resistance (i.e. shorted) the device recognizes that its connected to a charger and charges at the higher rate...
     
  17. hawkeye680

    hawkeye680 Member
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    I have the same one and it works well.
     
  18. sam007

    sam007 Well-Known Member
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    alright guys, especially hawkeye & woodrow, I bought the griffin and both ports show USB when charging. For the Bracketron charger, is it true that you get AC charging from one port and USB from the other?

    I can buy that but is there one that provides AC charging on both ports?

    Thanks
     
  19. WoodrowB

    WoodrowB Member
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    Sam007:

    yes, one of the ports on my Bracketron charges and displays on my GN as "AC". The other shows as USB.
     
  20. skiflyer

    skiflyer Well-Known Member
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    Buy the 2amp. They cost negligibly more and you're slightly more future-proofed.

    That said, I have the 2 port 2/1amp kensington and I had to crack it open and solder pins together to make it work right so my purchasing decisions may be suspect...
     
  21. Jedi54

    Jedi54 Well-Known Member
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    skiflyer: I bought 2 scosche chargers that only register as USB and I just ordered a griffin powerjolt hoping that will work as AC.

    If not, I suck at buying chargers (they're all rated at dual 1A) and will be spending some time trying to crack them open, soldering, and hoping I can put them back together without breaking them.
     
  22. Jedi54

    Jedi54 Well-Known Member
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    griffin powerjolt showed up yesterday, no dice.
    It charges as USB.

    Looks like I'll be trying to open that and a few Scosche chargers up this weekend to try and solder them.
    Anyone figured out an easy way to open the powerjolt?


    on a side note: I didn't realize how tiny that thing is, it's pretty awesome.
     
  23. speede541

    speede541 Android Enthusiast
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    Or you can purchase the Naztech USB charging cable on Amazon. It has the data leads shorted in the cable so you don't have to open the charger.
     
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  24. Jedi54

    Jedi54 Well-Known Member
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    thanks speede541 but $7 for a usb cable?
    I've got a ton of usb cables lying around the house so I'd rather just get a charger that can work with those.

    decisions, decisions...
     
  25. speede541

    speede541 Android Enthusiast
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    That's initially how I felt, but bought one anyway knowing I probably wouldn't get around to ripping open an adapter to solder connections. And it's unfortunate that the cable is a bit stiff and cheap feeling. But it does work, and it's not coiled, so I keep one in my car for charging and dash-mount nav duties.
     
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