Proper amperage for chargingTips


  1. SigNu747

    SigNu747 Member

    Looking to get a secondary charger and possibly a car charger and not looking to pay OEM retail.

    The print on included OEM charger reads: Output 5-15V & 2-1.2A (2-1.2A)
    Then, below that in another language it separated this to 5V @ 2A or 15V @ 1.2A

    My first question is what does this specific inverter actually output? If both, how/when does it know which one to choose?
    and
    Which one of these juice specs is ideal for prolonging battery life and charge cycles?
    I would assume the lower amperage, but 5V is basically universal as far as mobile device charging goes..

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  2. MSUgEEk

    MSUgEEk Well-Known Member

    5V @ 2A is typical for tablets. Any charger that outputs that should be fine.
  3. KouDy

    KouDy Active Member

    Simple 5V won't cut it for you. If it did, TF would charge from USB port on PC. I am afraid you need 15V one and that might be hard to get as USB because it's totally off the standards.
  4. MSUgEEk

    MSUgEEk Well-Known Member

    Tablets won't charge via USB because of amperage, not voltage. USB amperage from computers are limited to 500mA. ASUS apparently has something in their charging circuits that allow for faster charging at 15V @1.2A, however, it will also charge with the 5V @ 2.0A. Your standard 5V @ 2.0A will charge virtually any tablet. The 15V @ 1.2A for ASUS is just a faster charge option for ASUS products.
  5. ylexot

    ylexot Well-Known Member

    Sorry svt_gEEk, but you are apparently talking about something you know nothing about. The Transformer Prime requires 15V charging. It will not charge on USB. It is not "virtually any tablet". It is an exception.
  6. MSUgEEk

    MSUgEEk Well-Known Member

    Never said it would charge on USB.
  7. ylexot

    ylexot Well-Known Member

    It won't charge on 5V either.
  8. MSUgEEk

    MSUgEEk Well-Known Member

    My apologies if it doesn't. My Asus made Nexus 7 does and every other tablet does. Transformer prime must be an odd ball. I do realize there is a 15V output on that charger, but there is also a 5v @2A output as well
  9. breadnatty08

    breadnatty08 pain rustique VIP Member

    Was going to start another thread, but figured I'd dovetail this one.
    Been scratching my head about my Prime, but apparently it requires its original charger as none of my other wall chargers work on it (incl. the one for my N7, nor does my PC as ylexot said). Little bit of a bummer as I'm not sure where it is. :eek:
  10. theandies

    theandies Well-Known Member

    Wow, Manuals are great:
    [​IMG]

    It will charge on the USB port but it has to be turned off and it takes forever. My adaptor messed up while on vacation and I had to use the USB port to charge it and from about 20% to 100% took overnight on the USB and the Prime turned off.
    breadnatty08 likes this.
  11. breadnatty08

    breadnatty08 pain rustique VIP Member

    This thing came with a manual? :p
    JK, thanks for the info. I recall when I talked to HTC about my bricked Flyer he said the same thing about ONLY using the charger which came with the device.
  12. ylexot

    ylexot Well-Known Member

    Manuals will always say that to protect the manufacturer against the liability of damage caused by someone else's charger. However, the Prime has an additional reason in the needed voltage that USB chargers don't typically provide.
  13. Kookas

    Kookas Well-Known Member

    The official charger that comes with the Infinity is rated for 15V@1.2A, or 5V@2A, so I'm pretty sure it's safe to say that anything outputting 2 amps at 5 volts will charge the Prime (I can't see why it would change between the different tabs). My TF700 is on my bed right now charging from my external battery which does 5V@2A, with no problems or heat issues so far.
  14. ylexot

    ylexot Well-Known Member

    Ok, so it sounds like it will charge on 5V...just really slowly.

    15V * 1.2A = 18W
    5V * 2A = 10W

    So, charging with 5V at 2A (which is pretty rare) will charge at about half the rate of the 15V at 1.2A that the stock charger puts out.

    BTW, I'd bet that the only reason that the stock charger puts out 5V is because it uses a USB port. If it only put out 15V, somebody would plug something else into it and fry their device.
  15. theandies

    theandies Well-Known Member

    I tend to agree with you ylexot. I do use my Prime charging brick to charge my htc Vivid and it works fine.
  16. theandies

    theandies Well-Known Member

    I know right! Pretty much everything comes with a crappy "Getting Started" two page guide on how to turn on your new device and no real manual. When I get a new device I always go to the manufacturers site and search for complete manual. Some are really good and have good information, some are just one step up from the "Getting Started" guide.
  17. SigNu747

    SigNu747 Member

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