Android and Car Chargers

My car charger died recently, so it was time to shop for a replacement. The requirements started out pretty simple. I just wanted the ability to charge two devices (my phone, and either a passenger's phone or a Bluetooth headset) at once. That it's. But as I shopped, things got a little more complicated...

You see, Android supports two different charging modes. The first, AC, is what you get when you use the OEM wall or car charger. These provide the correct current (generally about 1 A for phones, 2 A for tablets) for that device. Your gadget is going to charge the fastest in AC mode.

The second mode is USB, which is used when the device is connected to a computer. But computers only provide 500 mA through their ports. That means it will take twice or four times as long to charge the battery. If you're using GPS, playing games, or streaming music over LTE, the charger won't be able to keep up.

The difference between the two modes is hardware. Chargers designed for Android have the middle two USB pins shorted to each other. A device looks at these two pins, and if they're shorted, goes into AC mode. If they're not, it will use USB.

As it turns out, most aftermarket car chargers don't have those pins shorted. Sure, they're capable of providing the 1 to 2 A your device requires, but your phone will only detect USB mode and use 500 mA. Note that Apple devices use a different method for deciding how to charge, so "Designed for iPhone/iPad" accessories won't help.

That leaves you with three options:

• Buy a charger that is known to work with your device.
• Buy any charger that provides the necessary current, open it up, and short the pins yourself.
• Buy any charger that provides the necessary current, plus a cable that has the pins shorted.

I ruled out option one because I couldn't find a charger that had two ports and was known to work with the Galaxy Nexus. Option two was out because I'm just not handy with a soldering iron (though that is a skill I'd like to develop).

So I went with option three. Amazon sells this cable (http://www.amazon.com/dp/B003VYBCAY/) for $8. I paired it with this charger (http://www.amazon.com/gp/product/B0056VNVV8) for $12. The Bracketron provides 1 A over one of its ports and 2 A over the other. That gives me the ports I need to charge two devices, and one of those devices can even be a tablet.

However, and this is very important,  if you go with the modified USB cable, make sure not to mix it up with your normal ones. You could damage your computer if you do.