So a few months ago, I stumbled upon a thing at Adafruit.com called a "Charger Doctor" which was really just a Multimeter designed to slip inline with your USB cable. It was $7.50 and I liked it.

This Gadget Freak review looks at a USB multimeter with an integrated OLED display to charge your smartphone rapidly. Then we look at the first USB Flash drive that allows connection through the Apple ...