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Support Can I use the 2 amp charger from my touch pad on the Gnex?

Discussion in 'Android Devices' started by mistermojorizi, Dec 16, 2011.

  1. mistermojorizi

    mistermojorizi Android Enthusiast
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    i believe the gnex is 1 amp charger. But someone elsewhere mentioned that the TP charger should work and even faster.
     

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  2. nkk

    nkk Android Expert
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  3. kklier

    kklier Member
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    I have used the 2AMP charger on my nexus today.
     
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  4. nkk

    nkk Android Expert
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    That was not a good idea. While it can be fine, you need to know a few things:

    amps matter less than voltage. IF it is pushing two amps at 5 or 5.5V, fine. IF it is pushing them at 7.4 or 10 V (like the ipad charger and a lot of tablet chargers), then you will have problems.

    If your phone works, it limits the current to a safe level anyway, so chances you are getting an actual 2A are low. You may be getting 1.3A or something like that, or you may still only be getting 1A. However, once you over volt (which a lot of those 2A chargers do...I have measured really cheap ones to go to 6.5 or 7V to get 2A into a phone battery), you are done.

    In general, unless all of the following apply, it is a bad idea to use them:
    -you know your phone battery's emergency cutoff circuit and voltage overages for current works

    -You know the charger keeps to the standard USB spec votage or a little above (5 to 5.5V is normal). Reading it is not enough...a lot of cheap ones are made to work at 5V but just do not because they are junk.

    -You trust the maker of your charger enogh to have not lied in their specs.


    Hpethat helps,
    -Nkk
     
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  5. speede541

    speede541 Android Enthusiast
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    Yes, it's safe, but it won't charge any faster. A AC/DC such as this -- especially one from a reputable manufacturer like HP -- will fall within the USB voltage output guidelines.

    The onboard charge controller (an integrated circuit onboard the phone) will take this incoming power source and "condition" it to the correct voltage to charge the battery in a very precise and controlled manner. The additional Amperage will only be called upon if needed / able to be used.

    The voltage requirements of these batteries is precise enough that the phone would never be left to rely upon an inexpensive external device like a wall wart to have "responsibility" for the battery's safe recharge. If the current output is insufficient, you'll be notified. But you're not in danger of pumping too much current into the phone -- it'll only use what it needs.

    If every USB plug was capable of outputting either insufficient or dangerous levels, resulting in all sorts of consumer headaches, exploding or otherwise dead batteries, think of the outcry!.This whole USB "universal" charge phenomenon that ended the hassle of proprietary charger connections is very well thought out, and has been successful for a reason.
     
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  6. jkc120

    jkc120 Android Expert
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    Thanks for the explanation. What about using my dinc charger? I want to keep one at work and one at home. The dinc charger is 1A @ 5.0v just like the gnex charger. In this case, should I be ok?
     
  7. bird jam

    bird jam Well-Known Member
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    I am using the cord I bought off Amazon for my HTC Incredible to charge mine here at work. I am assuming (hoping?) that it is safe. The Amazon page said it was specifically for the HTC Incredible and then when it showed up it had a BlackBerry symbol on the charging end. I am guessing they are pretty interchangeable but would appreciate someone telling me if they are not.
     
  8. edstewbob

    edstewbob Well-Known Member
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    Amps are pulled by the phone and not pushed by the power supply so as long as the voltage is the same it doesn't matter if the power supply can provide more amps than another power supply as long as it meets the minimum amp requirement of the device. I have purchased several laptop power supplies that provide more amps that the original and the only effect is that it does not warm up as much as the original.
     
  9. jimmypop13

    jimmypop13 Well-Known Member
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    I just realized I plugged my gnex into my moms charger instead of mine. Hers says Output:5v 500mA. Could I have done any harm? Had it plugged in for two hours. Only got half a charge
     
  10. speede541

    speede541 Android Enthusiast
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    No, you haven't done any damage. That's essentially the same thing as plugging it in to any USB port.
     
  11. T-Keith

    T-Keith Android Enthusiast
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    I have used my touchpad charger for my Incredible for a while, and used it on my Nexus today. It charges very fast, but the charge doesn't last as long if that makes any sense. Overall it is harder on the battery, but will work fine in a pinch.
     
  12. speede541

    speede541 Android Enthusiast
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    Hmmm... no, that doesn't make a whole lot of sense. I mean, yeah, the charging "faster" does because with the available current, it's going to charge at the max rate allowable. But not the part about the battery not lasting as long.

    I'd give it a couple of days of regular usage and charging to allow the system to settle down and then check this again, using some sort of methodical process, because you shouldn't see any sort of difference.
     
  13. mistermojorizi

    mistermojorizi Android Enthusiast
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    Thanks, that does help. It's 2 amps @ 5.3 V...so I take it this means its a fine daily driver for charging the gnex?
     
  14. kevinaminator

    kevinaminator Newbie
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    If the charger says 5V, 2A, it should have no problems. In fact, even if it says 5V, 100A, it will still be fine.
     
  15. kam187

    kam187 Android Expert
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    Exactly right. The only slight danger is using a cheap un-regualted charger. It won't ever be allowed to put the battery in danger but could over stress the charge circuit and damage it.

    Connector types are standardised for a reason, however the danger of overcharging a Lithium based battery means that stringent conditions are imposed to make sure an unsafe condition cannot occur. That generally means your phones charge controller will die before any serious issues with the battery. And thats the extreme case.

    If you want to be pedantic about it, the more stable voltage you supply to the phone the better. Any filter circuit is not perfect, and so a clean regulated and filtered supply will be better for your battery.

    In real terms, any micro USB charger from a reputable manufactuer should conform to limits set in the standard. So any Micro USB charger from an old phone should be fine.

    As for chargeing faster, thats unlikely. If the charger is 500mA, then it will charge like a USB connection. If its 1000mA (or 1A) then it will probably short the Data pins (and established standard for indicating AC power). If its > 1000mA or 1A then it must have a non standard way of indicating more current is available. That means to comply to standards it would only ever indicate 500mA or 1000mA/1A to a standard device.
     
  16. kam187

    kam187 Android Expert
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    BTW although the device will only ever draw what it needs, if it tries to draw more than it needs generally reaction time is slow. Power output (current x voltage) is slow to react, and a higher current draw generally results in a lower voltage. Worse a reaction which sundely drops current draw results in a voltage spike.

    This is why voltage regulation is important, and why Micro USB chargers will only indicate their current capability in a standardised way.
     
  17. syntrix

    syntrix Android Expert
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    Just verified those numbers on my touchpad charger.

    Should work just fine.
     
  18. speede541

    speede541 Android Enthusiast
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    BTW, just a little side anecdote:

    I have a 2-port 12v to USB adapter in my car that is capable of outputting 1A on each port. I was using this for at least a few weeks, probably closer to a couple of months to regularly charge my BlackBerry and power a Bluetooth audio device whenever the car was running. This was all through a generic 3' USB cable.

    Well, the time came for my car's Bluetooth speaker phone to be recharged, so I plugged it in to the generic cable and withing 10 minutes of doing so, noticed something was amiss. I touched the cable and it wasn't just warm, it was HOT. The current draw by the speaker phone must have been right at, or possibly exceeded, the adapter's limit. It certainly exceeded the USB cable's limit, damaging it beyond use.

    Everything else worked fine after that. And I purchased a more expensive Blackberry OEM cable that I knew was rated for a 1A charge, and that's worked fine charging everything -- including the power hungry speaker phone.

    Just just illustrates 2 things: Even if the source is rated at a high current output, it'll only give what's "requested" by the device being charged. And brand reputation does play a role in knowing & trusting the equipment.
     
  19. syntrix

    syntrix Android Expert
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    Even better example...

    You can use that 1A charger off of your 500A car battery :D:D
     
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  20. ez12a

    ez12a Member
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    For the record, what is the amperage of the included charger with the nexus? 5v 1A?

    i'm currently using a blackberry 5v 700 ma at home and it charges okay..
     
  21. mntbighker

    mntbighker Well-Known Member
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    I have a 12V dual USB car adapter rated at about an amp each. It was the only one I could find that could keep up with the drain on my DroidX2 with screen lit using Nav. The other ones I tried would leave the phone half charged at the destination. Unfortunately the GNex needs more current and the charger can't keep up. So does anyone know of any car USB chargers rated at more than an amp? I wonder what the USB specs have to say about this? Did Samsung design a phone that requires more juice than USB can provide with the screen lit and all radios on? I'm not even sure USB specs provide an amp.
     
  22. syntrix

    syntrix Android Expert
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    I've got the one that has a glowing VZW logo on it and it can certainly keep up with charging with nav on a SGN.

    Ugh, I should take a pic of that tomorrow... this charger charges FAST, very close to the wall charger.

    74% after down to under 10% in about 50 minutes... all while streaming music through bluetooth.
     
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