Troubleshooting Can I safely charge my Kindle 3 or Kindle DXG with my smartphone wall adapter?

[Tiersten]

Originally Posted by screwballl

The problem is the pins that connect to the devices themselves are typically custom for that device, even if the port itself is different.

No. Both ends are standardised. What you're experiecing is the different signaling methods to tell the device what the capabilities of the charger are.

The way it is generally done is to connect specific value resistors between the data pins and 5V & ground. The issue is that until recently, there wasn't actually any standard to say how that should be done and everybody generally did their own thing. Some very basic chargers wouldn't have anything at all connected to the data lines in the USB port. Others would have the resistors but they'd be different values or wired differently.

Some devices wouldn't care at all and would charge off anything. Some devices will default to the normal or slowest charging speed if it can't recognise the charger. Whilst other devices like Apple hardware would check and just refuse to charge off anything that doesn't conform to its standard.

What they're actually checking for using this signalling method is how much current the charger can supply. iPhones will charge slower off a PC because they're limited to 500mA but if you used the mains charger then it would know that it can draw 1000mA instead.

Originally Posted by screwballl

The USB specs only state that the square end like what plugs into a computer must conform to standards, at the other end companies can use whatever connector they want, even if it is the same as other devices.

Both ends are standard. What the Kindle uses is Micro-USB. Your PC will use regular USB. Most cameras I've seen use Mini-USB. Each of these types also have a subtype of type A and type B.

Regular USB has 4 pins but in theory should use type A and type B plugs to prevent you from connecting two USB host devices together directly e.g. PC to PC since thats not allowed without something in between. Micro-USB and Mini-USB have 5 pins and the 5th extra pin is wired to ground on one end of the cable to signify which end is what for USB OTG usage.

Recently however, they standardised on the Micro-USB standard for computer connection and for charging. Quite a few of the major consumer electronics companies have joined up for this.

[FF2]

I understand the European Union may be behind a more universal standard and it is the micro which the Kindle3 uses. My Blackberry can share it and I have swapped ac chargers.

My new nikon has yet another proprietary plug on the camera side of things - irritating as hell. My garmin and tomtom gps' both use the mini.

[carls_mc]

Has anyone tried this with an iPhone power adaptor and just swapping the iPhone/Kindle cables out?

[gdornick]

Originally Posted by carls_mc

Has anyone tried this with an iPhone power adaptor and just swapping the iPhone/Kindle cables out?

Yes, I have. I always charge my Kindle with the iPhone power adaptor, using the Kindle cable.
Works brilliant!

[carls_mc]

Awesome, thanks for that gdornick. One less power adaptor to carry round :-)

[Harmon]

Originally Posted by gdornick

Yes, I have. I always charge my Kindle with the iPhone power adaptor, using the Kindle cable.
Works brilliant!

I have an iPad, an iPhone 4, a Blackberry (work), a Sony 350, a Kindle DXG and a Kindle 3.

I use the Kindle plug and the Apple plug interchangably to charge all of these devices.

I use the Apple cord with the two Apple devices, and the Kindle cord with all of the remaining devices.

Everything charges, no fuss, no mess.

The only problem I have ever had is with the Apple cords, because some of them are evidently too old to couple with my iPad or the iPhone 4. Oddly, some of the Apple cords give me an iPad message telling me the iPad isn't charging, but they do anyway when connected to my computer - while continuing to give me the message.

[mrevent]

I hope this applies to the charger for ipad 3 as well?
(Output is 5.1V)

Edit: How on earth did I miss Harmon's post?!
Thanks and sorry!

[HarryT]

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