If you’ve ever wanted to build your own charger that works with the latest Apple devices, here’s how (schematics and video)…

In this 7 minute video we explore “The mysteries of Apple device charging“. Usually device makers need to sign a confidentially agreement with Apple who want to say “works with iPhone / iPod” and never talk about how the insides work. If you don’t put these secret resistors on the data lines to you get the dreaded “CHARGING IS NOT SUPPORTED WITH THIS ACCESSORY”. We demonstrate how anyone can do this and make their own chargers that work with iPhone 4, 3Gs, etc. Video above, HD and (m4v).


  • otterson

    33K to +5 and 22K to ground for 2 volts at the junction??? (22/55ths of 5 volts)

    Those are parts I have in my drawers…

  • RocketGuy

    Really nice and well produced, thanks so much!

  • Shadyman

    Sweet, though you know they’ll change the resistors for the next product release :(

  • arakawa

    I managed to make a no-brand usb charger work with my iphone 3gs just by shorting the data pins together. Don’t know about current flow, but it charges just as fast as the original.

  • Phillip Torrone

    @arakawa – the iphone 4 and 3gs “may” work by shorting the data pins, but that will not always work, it will not bring the phone “back from the dead” and basically you can’t count on it. good in a jam, but not for charging reliably.

    • arakawa

      Well, it should, according to http://pinouts.ru/Slots/USB_pinout.shtml

      Shorting the data pins signals the usb device that there is a dedicated charger connected. I don’t know how reliable that site is regarding the usb specification, but it has worked for me so far.

  • Phillip Torrone

    @arakawa – what apple does and what a “usb device” will do are different. if it works for you, that’s great.

    if you watch the videos you’ll see apple and the commercial approved 3rd party chargers do something else. if you check out the tweets and comments you’ll see many people who have chargers that do not work with the latest “i” devices.