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Topic: Why don't generic USB chargers work?

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Old 10-20-2007, 05:13 PM
#1
 
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Question Why don't generic USB chargers work?

This is my first ipod. Is there any way to get my generic USB adapters to charge my nano?

I've tried various USB chargers and with the included cable. No go. The only USB power that works is my PC.

Why is this? I don't want to pay $30 for the privilege of buying an authentic Apple charger (plus car charger).

Is there some kind of authentication chip inside the Apple charger? Is there a variation in the wiring of the charger or the cable? Does this issue affect other ipods?

There's a lot I love about my first ipod and a few things that really bug me. This is my biggest gripe. I live mobile. ALL my gadgets (phone, cam, DS, PSP, batt charger, etc.) now charge on USB power -- it simplifies my life and lightens my load.

If I have to treat my ipod like a privileged brat ("Ewww... generic USB!"), I may send it back. Thankfully Costco has that lovely 90-day no question return policy. I want my ipod to adapt to me, not force me to adapt to it. That's the whole point of a nano in my opinion - max convenience, minimum interference.

Thanks in advance!
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Old 10-20-2007, 08:26 PM
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apple uses a proprietary usb adapter that will only work with their cables. other cables will not match up with the pins in the iPod. i don't see what the big deal is with using the apple cable though? you are supposed to use the manufacturer cable with most mp3 players anyway; it's not a thing exclusive to the iPod.



3rd Generation Nano 4GB
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Old 10-20-2007, 11:14 PM
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I am glad I ran into your post, I thought I was the only one with this problem.

I agree. I couldn't figure out why all the products that say they will charge an Ipod don't. I am in the process of returning one now. I even just bought one set of chargers from Best Buy that are 'supposed to work' for my new ipod nano, but have been afraid to open the box because I don't want the 'drama' I have had with other products that are supposed to work with ipods. I didn't even realize it wasn't an ipod brand charger set, so I am seriously thinking of going to the apple site and get it from there. More money spent...UGH! Even my cell phone will let me use generic brands.

I really enjoy Ipod's products, but this proprietary issue, especially with 'car' chargers of all things has to stop!

God bless,
tamar


Quote:
Originally Posted by RajaJaja
This is my first ipod. Is there any way to get my generic USB adapters to charge my nano?

I've tried various USB chargers and with the included cable. No go. The only USB power that works is my PC.

Why is this? I don't want to pay $30 for the privilege of buying an authentic Apple charger (plus car charger).

Is there some kind of authentication chip inside the Apple charger? Is there a variation in the wiring of the charger or the cable? Does this issue affect other ipods?

There's a lot I love about my first ipod and a few things that really bug me. This is my biggest gripe. I live mobile. ALL my gadgets (phone, cam, DS, PSP, batt charger, etc.) now charge on USB power -- it simplifies my life and lightens my load.

If I have to treat my ipod like a privileged brat ("Ewww... generic USB!"), I may send it back. Thankfully Costco has that lovely 90-day no question return policy. I want my ipod to adapt to me, not force me to adapt to it. That's the whole point of a nano in my opinion - max convenience, minimum interference.

Thanks in advance!
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Old 10-21-2007, 01:10 AM
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I Suspect the Apple Charger Sends Data

Quote:
Originally Posted by espanoliPod
apple uses a proprietary usb adapter that will only work with their cables. other cables will not match up with the pins in the iPod. i don't see what the big deal is with using the apple cable though? you are supposed to use the manufacturer cable with most mp3 players anyway; it's not a thing exclusive to the iPod.
The problem I'm having isn't with the cable; I'm fine with carrying the ipod cable. It's just that the ipod (and cable) will charge from my laptop USB port but not from a generic USB charger or even a powered USB hub (if it's not connected to a PC). Every other USB-powered device I have works with any USB charger as does every MP3 player I've owned in the past (except those than ran on AAs or AAAs). I don't have a shuffle or older ipod, but I was under the impression that those *do* work with generic USB chargers. Correct me if I'm mistaken.

Also, the pins on the ipod cable do match up with standard USB cables, at least externally. I don't see how it wouldn't if it can plug into a standard PC USB port.

I'll have to experiment later. I'm going to try plugging my nano into a PC without iTunes. If my nano refuses to charge up on an iTune-less PC, then there is some communication that the nano is looking for before it will accept a charge. If that's the case, my suspicion is that there is some sort of chip or IC in the Apple-brand charger that sends the same verification code as the driver software. In other words, a dumb (power-only) USB port won't work.

If I had an Apple-brand charger, I would test the two inner USB leads with a digital multimeter. Power for USB is supplied on the two outside pins (1,4), data on the two inside pins (2,3). A power-only port should either be missing the two inside pins or else (I'd imagine) not have them connected to anything. I should see infinite resistance across pins 2 and 3 on a dumb port. I suspect an Apple-brand USB charger will register some kind of activity on the two inside pins and/or a non-infinite resistance.

The other thing I may try is to put a piece of paper or tape over pins 2 and 3. That will allow power but no data. My brother does that with his Sansa so he can listen to it while charging (otherwise it goes into synch mode). If my ipod refuses to charge with those two pins covered, then there is definitely data that starts the charging. Shoot. I could have easily tested that theory in the time it took to write this. It's late. I'll test it tomorrow.

If the nano requires communication from the charger, then I'll just have to bite the bullet and buy an Apple charger or some other name-brand that guarantees compatibility. Or return the nano to Costco. But if it's just some funky wiring shenanigans, maybe I can rig a cable or an adapter or something.

I'd appreciate any definitive info on this. If there is a verification chip in the Apple charger, I'd love it if someone came up with a cable that contained the chip so I could just use any generic power-only USB port. I'm also hoping that there is a good consumer-friendly reason Apple chose to make the nano 3g not work with generic USB. I hope the reason is not just a desire to make everyone pay $30 for a charger with >50% profit margin. I thought the days of Jean Louis Gassee were done.

Sorry for the long, thinking-out-loud post.
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Old 10-21-2007, 04:11 PM
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This is something I am going to have to experiment with myself, and re-post here in a bit.

I have a 3G Nano, as well as 2 different type bateries with USB ports in them for charging USB devices. Right now, when I plug either in to the Nano, it sys fully charged (I charged it last night). I'm going to keep th backlight on for a bit and see what happens when I try to charge it using one of these batteries.
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Old 10-21-2007, 04:37 PM
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Nope, doesn't work with the external batteries. Damn!!
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Old 10-21-2007, 06:41 PM
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I have done some testing and I believe the difference lies in the amount of current the newer Nano requires to charge rather than any data signals. I have a power panel I installed in my car, has 2- 12 volt sockets and 2 USB socket. Just power no data capabilities at all, charges fine. I have several older 12volt and 120 AC usb chargers (generic) none will charge the Nano using the Apple cable. It looks like most of these adapters put out around 250-320ma max. However, my older Monster charge adapter cable w/ dock connector and line out works well (no current rating on it though) and my new Kennsington fm mod/ charge adapter (not designed for the 3G nano) works fine. My educated guess is that they provide much more current as does my power adapter in the car (I think it is rated @ 5v/500ma, but it's difficult to verify as it is now buried in the dash). Hope that may help some...K
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Old 10-21-2007, 10:25 PM
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G26K, thanks for you input! Curious, but your results are different than what I'm seeing. My Dell laptop USB charges my nano just fine but quickly shuts down when trying to run my external 2.5" hard drive. Laptop USB ports are notoriously stingy with power. In contrast, my Belkin USB 7-port powered hub with it's massive 2A power supply, much more than the 1/2 amp (500ma) you mention, fails to charge my nano unless connected to my laptop.

I also tried my Monster USB car charger, made and marketed for the 1st-gen Shuffle. It doesn't work either. I've been too busy to run any other tests, especially since I'm watching the Sox game right now. Hopefully tomorrow.

Last edited by RajaJaja; 10-21-2007 at 10:30 PM.
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Old 10-22-2007, 10:38 AM
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Ok, I just ran my test. I covered the data pins on my ipod USB cable and it would no longer power up when connected to my laptop.

I then connected my nano to a laptop that does not have iTunes installed. At first, the display came on (as it does when connecting to any dumb USB power), but no charging took place. WindowsXP then gave me a message that system settings had been updated and I needed to reboot. In other words, some driver and/or service had been installed. As soon as that happened (even before the reboot), my nano started charging and said "connected..."

Here's what's going on:
Attach cable to nano but leave USB end of cable not connected to anything - nothing
Attach cable to nano and dumb USB power (no data) - display light comes on but no charging
Attach cable to nano and laptop USB without iTunes installed - initially same as dumb power until Windows installs drivers and/or service - then charges and says "connected"
Attach cable to nano and laptop USB with iTunes - charges and says "connected"

There is obviously some type of data being sent across those data pins.

The question I have now is:
What does the nano display show when connected to an Apple USB charger? Does it just charge, or does it say "connected" like when hooked up to a computer?

I'm so curious now that I might buy an Apple charger just to take it apart and see what's going on inside.
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Old 10-23-2007, 02:07 AM
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RJ, Let me know how you come out. I have seen the nano 3g over current the USB on my Clevo Laptop, but only rarely and not since I added the wall wart for the 7 port hub I am using. I re-checked the others I mentioned to ensure I had it straight ( I am getting to that age!) and they work as mentioned. Good luck...K
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Old 10-23-2007, 11:18 AM
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I too have a bad experience with generic USB chargers (those that look similar to the original iPod charger from Apple). Then the guy from the shop I bought the charger recommended me a different kind of charger, it is a direct charge concept (you won't need to plug the iPod sync cable to the charger) and it charges fine.
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Old 10-23-2007, 03:56 PM
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My experience is very similar to that of RajaJaja, except that I have not even tried a generic USB charger -- was going to make one, but that's now on hold.

Attach cable to nano but leave USB end of cable not connected to anything - nothing (duh)

Attach cable to nano and dumb USB power (no data) - display light comes on but no charging
I did this with a machine with no RAM, but +5.05 Volts coming from the USB port

Attach cable to nano and desktop "A" USB without iTunes installed - initially same as dumb power until Windows installs drivers and/or service - then charges and says "connected"
On this one when I ejected the drive it stopped charging (lightning bolt went away)

Attach cable to nano and desktop "B" [I]USB without iTunes installed - Windows already had drivers it needed, connected and charged and continued charging after drive was ejected. On this machine also booted up Puppy Linux and it connected and charged.

Attach cable to nano and different desktop "C" USB with iTunes - charges and says "connected"

I also noticed that on Desktop "A" from a cold start there was no charging until after Windows booted. On Desktop "B" from a cold start there was first charging, then it stopped partway thru the boot process, then began charging before Windows had booted and continued to charge.

Sure looks to me like the computer needs to exchange some minimal info with the nano to initiate charging. If it's using a similar charging controller chip as the mini, this wouldn't be hard to implement. Can't account for what G26k is seeing, though. Maybe he got an unlocked one!
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Old 10-24-2007, 05:42 AM
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Pull up resistors on the data lines?

BoxWave is selling a device that looks for all the world like a short USB extension cable but makes this claim:

"BoxWave’s specialized iPod Charging Adapter is the only adapter available that allows 100% backwards compatibility with any USB charger. Previously, there was no solution for allowing Apple iPod nano 3rd Generation users to use their other USB charging accessories in conjunction with the Apple iPod nano 3rd Generation. Now with the iPod Charging Adapter, your options for Apple iPod nano 3rd Generation chargers have been expanded wide open."

http://tinyurl.com/25blld

They also sell something similar for the iPhone, discussed in this thread:

http://www.ilounge.com/index.php/new...rging-adapter/

which contained (among others) these comments:

"Looks are deceiving—that’s the only charging adapter in the industry that can retrofit a regular USB charger to power an iPhone. It bridges the gap between a generic USB car or wall charger to the iPhone provided cable so you don’t have to re-buy new chargers for the iPhone.

[full disclosure—I work for BoxWave]
Posted by Wing on August 24, 2007 at 10:41 PM (PDT)
"

-----

"Most likely, this charger adds pull up resistors on both D+ and D- lines of the USB, which the iphone seems to require in order to charge.

The USB spec does not define this, and therefore many USB chargers do not have this resistor, and therefore do not work.
Posted by Michael Ducker on August 27, 2007 at 1:31 PM (PDT)
"

-----

"My apologies for not elaborating the technical points—I mistakenly assumed the charging problem was well known.

Take care,

Wing Yew
"

-----

will investigate further.
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Old 10-24-2007, 03:52 PM
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Quote:
Originally Posted by hermit3d
Attach cable to nano but leave USB end of cable not connected to anything - nothing (duh)
Ok, I should have explained that note was to show that just plugging the cable in didn't turn on the display -- the cable had to have power in order for the display to come on. However, as the other tests show, having power is not sufficient to initiate charging.
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Old 10-24-2007, 04:37 PM
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hermit3d, thanks for the info on the pull up resistors on the D+ and D- lines. I think that's it. I'll verify with my multimeter later.

I'm no EE, so I looked up the USB specs and pin 1 is 5v power, pin 2 is D-, pin 3 is D+ and pin 4 is ground. From what I gather about pull-up resistors, it stabilizes the D- and D+ lines to a known state of 5v when the circuit is open.

That certainly seems to explain why something is going on with pins 2 and 3. I borrowed a Griffin charger today that works for my nano. Plugging it in doesn't bring up the "connected" screen but it does put a lightning bolt inside the battery icon to tell me it's charging. Sure enough, when I block pins 2 and 3 on the Griffin charger, it acts just like a generic USB charger, i.e. it refuses to charge. Also, a 10k pull-up resistor makes sense as it would cost a lot less than any verification chip.

That boxwave product seems like just the thing. It's small, overpriced but still cheap, and would allow me to use all my current hardware. I can live with that.

Last edited by RajaJaja; 10-24-2007 at 04:39 PM.
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Topic: Why don't generic USB chargers work?

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