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12V DC to 5V DC iPhone Charging

Discussion in 'General Electronics Discussion' started by Brad93, Aug 13, 2013.

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  1. Brad93

    Brad93

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    Aug 13, 2013
    Hi Guys,

    I'm new here, not done much with electronics except A-Level physics and my own research.

    I'm trying to build a circuit to use a 12V 7ah battery to charge my iPhone 5 which I have found requires a stable 5V supply and i can charge at up to 2.1Amps. (10Watts)

    Would the best way of doing this be with a 7805 IC voltage regulator with heatshield and a 100uF capacitor and a 0.1uF capacitor on either side along with a 2 amp fuse?

    Also would anyone be able to advise me if i could install a battery indicator of the source batterys charge? I've been looking at something along the lines of this?

    http://www.electroschematics.com/6868/12v-battery-level-indicator-circuit/

    Any help greatly appreciated.
     
  2. BobK

    BobK

    7,682
    1,688
    Jan 5, 2010
    If you use a 7805 you are wasting 7/12 = 58% of the energy. Use a DC-DC converter, which can be up to 90% efficient. You can find these cheap on Ebay.

    Also, be aware, that for Apple phones, you will have to put certain voltages on the D+ and D- lines of the USB connector in order to make it charge at 2A.

    Bob
     
  3. Brad93

    Brad93

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    Aug 13, 2013
  4. BobK

    BobK

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    1,688
    Jan 5, 2010
  5. Brad93

    Brad93

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    Aug 13, 2013
    Thanks for that bob. In what order would i wire that in order to get 5V? I really am a newbie with all this and google hasnt thrown up much.

    Thanks for your advice
     
  6. Brad93

    Brad93

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    Aug 13, 2013
  7. davenn

    davenn Moderator

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    Sep 5, 2009
    its ready built for you!!
    it has 2 wires in and 2 out ... they are labelled. you put a meter on the output and adjust the trimmer for 5V
    its a no brainer ;)



    yoah it will but thats just the chip ... you would have to get the other components and make a circuit board and put it all together
    it ISNT ready built for you and you couldnt buy all the parts for the same price that the ready built one is !!
    and since you have stated you are a newbie .... you are going to probably struggle building it

    Dave
     
    Last edited: Aug 13, 2013
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,482
    2,830
    Jan 21, 2010
    Got a spare dollar?

    I'd get something like this.

    Does iPhone 5 charge from USB?

    Go to ebay, search for "iphone 5 car charger" and then sort by price. These car chargers can typically be pulled apart very easily and you can then use the module inside.
     
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