I have a 10,000ma/h battery pack i carry with me that I charge my phone with; when that runs out i charge it with any wall jack / usb port i can find.

Effectively the same thing, and portable!

Swappable battery > plugging in to charger in everyway. I'm amazed only a few phones have the ability to swap batteries.

I thought the argument against this was that then you lost volume to the casing, connector, removable cover, etc. which could be better used by a funny-shaped collection of various-sized batteries.

Battery swap requires a reboot (usually) which is bit annoying.

Do you know of any devices that don't require a reboot when you switch batteries? It shouldn't be difficult to implement. All you have to do is build a small second internal battery into the device that could keep the volatile memory alive during the switch.

But then there's no perceived need for it for 99% of users so, like many neat things, it will unfortunately never be built into mass-produced phones because it doesn't make business sense.

That same idea is apparently there in the upcoming Thinkpad T440s laptop (3 cell internal + 3 cell swappable). I really hope it catches on in other laptops and phones - I find I often go past a typical phone & laptop's battery span without a power plug around.

Thinkpads have supported a second battery in the UltraBay for a long time, as well.

FYI, they had this feature on PDAs of yesteryears since their battery life was terrible.

[RIP my Axim X30]

LOTS of phones allow a battery swap. As far as I know the only phone that doesn't is the iPhone.

Nexus 4 doesn't have an easily replaceable battery either.

Sony Xperia S, probably others. Plenty of phones have non user replaceable batteries.

New nokias don't.

iPhone, Nexus 4, and HTC One

Moto X

Wouldn't try it with the HTC One X

But if you swap batteries, then when you get to an outlet, you either need a special charger for the spare battery, or you need to swap batteries while charging.

the main reason to have spare batteries for me at least is to keep the spare batteries charged up and ready to roll. But yes this does require a specific battery charger. when i had my HTC Thunderbolt, i got a package deal with 2 batteries and a charger ( that also provided a USB port ) for < $20. I haven't looked for my S3 yet...

Like this?

http://www.amazon.co.uk/Power-Only-Charging-Cable-Extension/...

"The CDL-02POWER is a type A male to type A female extension cable with only the + and - power pins connected.

This is extension for charging devices like ipods, Sat Navs etc. It allows you connect the appropriate device cable and charge the device through your USB port on your PC/Laptop with out opening up your webstore, itunes etc. While a device cable has data and power only the power from the extension is carried through.

Please note that due to limitations of 500ma output from a USB port, some devices may take longer than others to charge. "

The last line is the disadvantage. You need the data pins to enable high-current charging. I suppose you could create a digital "transformer" to isolate the iDevice from the port while still enabling high-current charging.

Could you include an inductor to prevent the data bits from changing fast and connect both lines to the power line so that if the power line was actually compromised the inductor would stop the attack.

You could just cut the data wires of the USB cable you wish to use. Simple, cheap and effective.

That would not work. Data pins are used to provide power negotiation, and in Apple's case using a proprietary protocol. At the very least you need some specific voltages on the lines to make it charge.

http://www.idownloadblog.com/2012/05/21/apple-power-adapter-...

http://learn.adafruit.com/minty-boost/icharging

I imagine basically all of those convenience ports only put out 500mA anyway, so the negotiation isn't needed.

iPads require more juice. Whenever I plug my iPad into anything other than Apple's 10W adapter or a Mac, nothing happens.

I plug my original iPad into other USB devices that put out 5W and it still charges. The iPad says it's not charging but it does, slowly.

http://www.indiegogo.com/projects/portpilot-charge-with-spee... :)

(not affiliated)

There are already such devices on the market. I just bought one three weeks ago for about $12. It even has a plug for car cigarette lighter (which is actually why I bought it).

It's called "3-in-1 charger" here in Europe and it looks like this:

http://mireltech.ru/node/614

What the GP is talking about is a little female-microusb to male-microusb that disables the data pins so you're sure the only thing going on there is charging.

I found this http://www.kickstarter.com/projects/671390578/juicebee recently which looks like a good compromise. There are many similar products on amazon as well.

Not exactly what you want, and limited to UK use, but I carry one of these around with me most of the time: https://www.themu.co.uk/

It's even smaller than I thought it would be, and so much more portable than a normal UK plug.

From the last time this came up, I found a few: https://news.ycombinator.com/item?id=5814193

I'd pay decent money for a small, USB adapter with the ability to swap the pins (for international travel) and a guarantee that it would reach at least 1.8A and 5V.

You pretty much just described the Apple charger. 10W, with multiple duckheads, will take any voltage and has the option to plug any standard figure 8 cable in if you have one lying around.

I'm so conflicted right now... I don't own any other Apple gear.

And? Its just a charger, not like you're supposed to convert to a new religion or anything.

Use this instead: Amazon Charger (usually shipped with a Kindle)

http://www.amazon.com/dp/B005DOK8NW/

I believe those are 5 watts. That is the kind I've gotten with my eink kindles but my, kindle fire came with a different charger that I believe is 10 watts. I don't have any of them on my at the moment to check though.

the product name is

    Amazon 5W USB Charger

Ha, so it is. I only glanced at the picture.

This looks like it would do what you want: http://www.kickstarter.com/projects/david-toledo/the-practic...