Update on the USB charging problem of the iPhone 3G

After I posted my last article I decided to do some experimenting based on the description of the DIY iPhone 3G charger I linked to.

I checked the two travel chargers I have, and just as expected: The one that charges the iPhone 3G has a 2.4v and 2.8v reference voltage applied on the data pins in addition to the 5v charging voltage. The one that charge my iPod but not my iPhone have no voltage on the data pins.

So, I guess the solution is to make a small adapter that gives the required voltage on the data pins: USB in, some resistors and USB out. Like described in the article about the DIY iPhone 3G charger.

That simple adapter will solve the problem of some of the USB chargers that won’t work on the iPhone 3G, but not the problem with the equipment that use the old FireWire method of charging (like the Dension ICElink in my car). For that you need a slightly more advanced adapter.

Update on the USB charging problem of the iPhone 3G

16 thoughts on “Update on the USB charging problem of the iPhone 3G

  1. Knut A. Helgeland says:

    Well, since all you need is a USB plug with the correct voltages, it should be just as simple to build from a firewire charger. 10 minutes at ELFA.no will get you all the parts you need! 😉 K

  2. Here’s an odd thing – I got my iPhone3g a couple of days ago, and they explained in the shop that to get it working, I just needed to connect it to my PC and download iTunes and follow the instructions.
    When I powered on the iPhone, it was telling me to connect to iTunes, with no other options available.
    First problem – My PC runs Ubuntu (Linux) not Windoze, so iTunes won’t work. I also noticed that the USB port wasn’t charging the iPhone either, so I plugged the lead into my existing 2 port Mains USB Charger – that didn’t work either! Dug the supplied mains adapter out of the iPhone box – no problem.
    With the iPhone part-charged, I went upstairs to daughter’s PC which runs Vista, so no problem with iTunes and getting the iPhone working, but at some point, I had to re-boot the PC and whilst this was happening, went off to make a coffee.
    When I got back, daughter’s PC had booted into Ubuntu (it’s a dual-boot) and I noticed again that the USB port didn’t charge the iPhone!
    Same story with my Laptop – Charges the iPhone when running XP, but not when running Suse10 (Linux).
    There are a few devices around the house that use the USB port for charging – Sat Nav, various phones, cameras and MP3 players, and most of these came with Mains or Car Adapters, so I decided to do a quick round-up and this is what I found:-
    Only the iPhone Mains Adapter charges the iPhone, but not when connected to the cable using a USB extension cable or USB Hub. None of my various Car Adapters work either – including the one that works with daughter’s iPod.
    The iPhone Mains Adapter charges everything else – with or withous a USB extension lead or hub in the link.
    I have a PC that charges the iPhone when running Vista, but not Ubuntu.
    I have a Laptop that charges the iPhone when running XP, but not Suse 10.
    I have a works PC that doesn’t charge the iPhone when running Windoze 2000.
    The iPhone USB Cable charges the iPod, but the iPod cable doesn’t charge the iPhone.
    The USB cable that came with the iPod fits the iPhone correctly, but causes an error screen to appear on the iPhone, saying that charging is not supported.
    No other combination of charger or cable gives this message.
    I imagine that the iTunes software is not available to Linux users out of sheer spite – there’s no technical reason to sacrifice a potential market when it could easily be made to work – but I can’t figure why simply charging the iPhone should be so dependant on hardware or Operating System.

  3. Interesting indeed! Maybe I’ll have to install Ubuntu on one of my boxes to check the following: if windows and OSX gives the 2.4 Volts of reference power and Ubuntu won’t?

    And here’s another strange story:

    A while ago I bought a separate solar charging battery. Through the adapter I’ve described here it charges my iPhone. And my coworker’s 8 GB iPhone, and NOT my other coworker’s 16 GB iPhone… Those extra 8 GB drains a lot of extra power or what?

    Apple have not made this easy for us!

  4. Gerryep says:

    I have just bought a iPhone 3g and have the problem with the message “This accessory etc” however it is docked in an Athena iVoice and appears to be charging, receiving calls (with a stronger mobile signal than when out of the dock) it plays music, sends texts and receives emails.

    Is it possible that the only problem is that there will be interference to the ipod side of the device if a call is received – in which case, so be it.

    My only concern would be if I am mangling it’s innards – destroying the battery, voiding the warranty et al.

    Anything known?

    Many thanks.

  5. I don’t think this would harm your iPhone. If it says the accessory is not suited but it still charges etc, then I think you’re all fine. Seems like the circuits that handles the charging is very well secured. This device is in general pretty picky about what charge it lets trough. If it charges, I guess it’s OK.

    But, I won’t take any responsibility here… Charge at your own risk. 🙂

  6. Iggy says:


    When the iphone is plugged into your Ubuntu PC try removing the ehci module ie:

    sudo rmmod ehci_hcd

    That should get the iPhone 3G at least to charge from your PC.

  7. filmteknik says:

    iPhone will not charge if simply plugged into any old USB jack…even though the 5VDC power is present. Either a data connection has to be established (not entirely sure if some part of iTunes is needed or not) OR there must be a couple of volts on the two data pins.

    That’s why it won’t charge from a random USB charger that charges everything else. It also explains something I noticed where my new 3GS would not charge from an old Windows 98SE box. The OS gets corrupted pretty often on that machine so too many times to count so I reload it and everything. (Yeah it’s stupid that I put up with it.) Anyway, last time I didn’t do a good job and some drivers didn’t get loaded right including for the USB ports. That probably explains why there was no charging when I plugged even though there is power any time that machine is on.

    Here is more information:

  8. Xyxo says:

    Just got a used (but in perfect shape) iPhone 3G but the guy lost the wall charger about 2 days before I got it and he said no problem, just charge it with any USB port on any computer.

    Well, I’m currently running 7 Ultimate (64-bit) and I plugged in last night to charge up and this morning I had 16% left (down from 61% when I plugged it up!)

    One question before I go further, does an iPhone really drain that much power when merely sitting there?

    I have another phone with a bad battery that I have to put on the charger every single night. (It used to hold a charge for 3 or 4 days, even with a lot of talking and texting).
    Anyway, will I have to repeat that rig-a-mar-ole with my iPhone, i.e. charge every night?

    I read a lot of Googled topics on the subject of iPhone not charging when hooked to certain computers with various operating systems, and I noticed a few talking about installation of iTunes (for what!?).

    So, I bit the bullet and d/l and installed iTunes.

    Now my iPhone charges up flawlessly!

    Something I didn’t expect happens.
    When I plug the phone into a USB port, no iTunes opens, no pop up saying iTunes is communicating with the phone, nothing. It just charges.

    1) Wouldn’t charge before.
    2) Installed iTunes (v.10) and now it charges , no questions asked.

    Go figure.

    Thanks, Apple, for making a simple thing difficult.


  9. Alan Reeves says:

    iTunes in needed before you can use a new iPhone for the first time, for updates to the OS, and for adding music and videos.
    Installing iTunes onto Windoze seems to do something to the voltages on the USB port, but there is much better support on Ubuntu – which I noticed when I installed a recent free upgrade.
    Ubuntu now charges the iPhone correctly through the USB ports and also allows a limited amount of browsing.
    I can now even upload music files and other data via Ubuntu and transfer them to other PCs, but can’t play those music or video files on the iPhone!
    Still no Ubuntu version of iTunes (yet) but that is only because Apple have inserted extra code in the software to test the operating system – if they just left it out, it would work on anything!

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