I solved my slow charging external USB battery problem
So, I recently purchased an external USB battery (sometimes called a "USB power bank"). In use, it seemed to charge my phone slower than it's labeled 5V/1A output. After some research, I learned that many devices (such as my Galaxy Nexus) limit themselves to drawing .5A from a standard USB connection, but will draw more from a wall charger. It turns out that some wall chargers short the data pins, which tells the device it can safely draw more than .5A.
I concluded that the battery does not short the data pins, and the phone sees it as a standard USB connection. It's either modify the battery, or the USB cable. The battery has a plastic shell with no visible screws, so.. cable it is!
A quick search lead me to this article on how modify a USB cable to be "charge-only" and let the phone draw more juice from my battery.. I did the modification in about 10 minutes using only a swiss army knife and some duct tape, and am VERY happy with the results!
This works for more than just Blackberries! (But be warned - If you try this, it is at your own risk!)https://www.ibm.com/developerworks/community/blogs/gg/entry/blackberry_charging_issue_solved_hack_your_usb_cable_today?lang=en#thereifixedit