1. jrtesq's Avatar
    Recently switched from Palm Pre to iPhone 4s.

    I have 3 or 4 Palm Pre wall chargers lying around. The Palm wall adapter accepts a USB plug. Obviously, the iPhone sync cable fits into the Palm adapter, but will it fry my iPhone if I try it?

    Assuming it won't fry the phone, will it actually charge it?

    It would be nice to use these wall chargers instead of having to buy iPhone specific ones.
    03-16-2012 03:54 PM
  2. ame's Avatar
    No, you need to use the apple ones. The Pre one won't do anything. The iPhone doesn't have inductive charging like the Pre did. RIP PRE.
    03-16-2012 03:59 PM
  3. jrtesq's Avatar
    Not talking about the inductive charger.

    The wall adapter (thing I plug into the outlet) accepts a USB cable, just like the Apple wall adapter.

    The Palm Pre did not need the inductive charger (touchstone) to charge. The Pre could charge by just plugging the USB cable into the adapter.

    I really hope you didn't think I wanted to use a touchstone with the iPhone.
    reltm likes this.
    03-16-2012 04:09 PM
  4. ame's Avatar
    No. The chargers are not the same pins.
    03-16-2012 04:10 PM
  5. jrtesq's Avatar
    Ok. Thanks. I appreciate the help.
    03-16-2012 04:11 PM
  6. jrtesq's Avatar
    Ok, so I continued my research using the Google machine, and I actually came up with a prior thread on this topic in this forum (I missed it during my initial search).

    http://forums.imore.com/iphone-acces...iphone-4s.html


    It seems to indicate that the Pre wall adapter will work.

    I also found a few threads in other forums that indicated any usb wall adapter that puts out 5V at 1A will charge the iPhone. The Pre wall adapter puts out 5V at 1A.

    So, although I appreciate Ame's insight, does anyone else have some experience with or knowledge of this topic?

    Thanks.
    Last edited by jrtesq; 03-16-2012 at 11:59 PM.
    03-16-2012 06:25 PM
  7. DavidF78's Avatar
    Ok, so I continued my research using the Google machine, and I actually came up with a prior thread on this topic in this forum (I missed it during my initial search).

    I do not have enough posts to include a hyperlink to the thread, but it can be found at:

    forums.imore.com/iphone-accessories/222765-palm-pre-adapter-used-iphone-4s.html


    It seems to indicate that the Pre wall adapter will work.

    I also found a few threads in other forums that indicated any usb wall adapter that puts out 5V at 1A will charge the iPhone. The Pre wall adapter puts out 5V at 1A.

    So, although I appreciate Ame's insight, does anyone else have some experience with or knowledge of this topic?

    Thanks.
    I use mine all the time. I also use one from a Motorola droid. The apple charger is still in the box in its plastic sleeve waiting to be resold when the next iPhone comes out.
    jrtesq likes this.
    03-16-2012 08:41 PM
  8. jrtesq's Avatar
    I use mine all the time.
    Thanks David.

    I also have a Palm Pre car charger. You think it will work too? Call me paranoid; I just don't wanna fry my new phone.
    03-16-2012 09:31 PM
  9. ame's Avatar
    If you're concerned about it, I don't understand why using the one that came with the phone is such an ordeal. I have never tried, as the connection was not the right size connection (30pin) for the iPhone and because the iPhone came with a charger.
    03-16-2012 11:27 PM
  10. jrtesq's Avatar
    I don't understand
    I believe you.
    03-16-2012 11:58 PM
  11. reltm's Avatar
    This is a great question. I wish we had some engineeres who could speak to this issue as it comes up a lot.

    If the charger has the same voltage and amp rating and the polarity and pins are aligned, I will say with 95% certainty you're good to go. (you may ask what that's worth -- well, I'd wager my $700 iPhone on it... And I don't gamble).

    Since you are using the stock iPhone charging cable and a generic USB port charger, I think you can safely assume the pins and polarity are aligned. The question that usually comes up is "the volts/amps don't match the factory charger. Can I still use it?" the general answer (and I've never gone wrong or read otherwise) is that it is imperative to match voltage. Don't mess around with different voltages because then you will get into trouble.

    Amps on the other hand can be rated higher on the charger than what the device will actually pull. As long as the voltage is matched and the charger is rated for a higher number of Amps than what is listed on the device, you will be okay using that charger with that device.

    A further question is often what happens if the voltage is rated slightly differently, like I've run into chargers that are rated for 5.1 volts and I have a 5.0 volt device. I really don't know in this case, except to say I've taken the risk on occasion and haven't had any bad consequences yet. But maybe it's a long term thing.

    Those Pre chargers are great though. I picked up a couple myself to specifically use to charge iPhones, iPods, and other cell phones (that all have the 5.0 volt requirement and draw 1amp or less).
    jrtesq likes this.
    03-17-2012 12:47 AM
  12. Timhewitt's Avatar
    The iOS device charging circuitry has to deal with a wide range of variation in USB computer hardware, as well as the designed power supply of the iPad charger for the iPhone or iPad.

    This means it's fairly forgiving, but you should be aware of what your charger provides before just plugging it in.
    jrtesq likes this.
    03-17-2012 06:56 AM
  13. DavidF78's Avatar
    Thanks David.

    I also have a Palm Pre car charger. You think it will work too? Call me paranoid; I just don't wanna fry my new phone.
    I am quite sure it would. I don't have a palm branded car charger but if I did I wouldn't think twice about using it.
    This is what I am using in the car.

    Amazon.com: Griffin Technology 1 Amp PowerJolt Dual for iPhone and iPod (Black): Cell Phones & Accessories
    jrtesq likes this.
    03-20-2012 09:55 AM
  14. vreihen's Avatar
    I have been using my Palm car and wall chargers with the iPhone USB cables for a few weeks now. Nothing has blown up yet, and my new iPhone 4s sat on my desk charging all day.

    When the Palm Pre chargers came out, they needed 1.0 amps to run the touchstone. The aftermarket and other phones were usually shipping with 0.8 amp chargers at the time, which didn't work properly with the touchstone. The Palm car charger was the key to mounting a touchstone on your vehicle, as everyone quickly learned. If I recall correctly, Palm connected the two *data* pins together in some way inside their USB chargers, so that the phone could detect the higher 1.0 amp power being available versus the 0.8 amps on a regular USB port.

    In any case, I have been charging a demo iPhone 4 and now my new 4s for about three weeks using only the Palm USB chargers with the Apple USB cable, and they haven't exploded or exhibited any signs of a problem. The one thing that I *did* discover today wasn't compatible with the Palm charger was a co-workers iPad. The owner said that the iPad doesn't charge from a PC USB port either, only the Apple chargers. I guess they have another way of detecting 1.0 amp chargers that isn't compatible with the Palm method?

    As for using your touchstones with an iPhone 4s, there's a blog post showing some guy's hack showing that it is electrically possible if you Google for it. If I can find a right-angle dock connector and an iPhone accessory case to transplant the touchstone charging coils into, I may wind up trying to make a usable version of his circuit myself one of these days.....
    reltm likes this.
    03-26-2012 07:41 PM
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