One of my random Chinese purchases recently was a little device that measure how much current is being sent through a USB cable or being provided by a USB charger. What drove me to buy one of these? Curiosity!

I have a lot of USB chargers that I’ve accumulated from buying gadgets. I also bought many chargers independently because I wanted chargers with multiple ports, or chargers that provided higher current (random Chinese charger would provide 0.5A, but I wanted “tablet” level ones that provide 2A), or both! After a lot of experimentation to see which is better, I’ve settled on the Blackberry Blade chargers and have bought 6 of them. They don’t have a separate USB cord, but they consistently charge fast (rated at 1.8A). I don’t use any of my other wall chargers now.

So it might seem that this little dongle is useless to me, but I actually spent a few hours doing tests on my USB cables. Like chargers, I have many from buying gadgets, and a lot of different colored/designed ones from Deal Extreme. Surprisingly, I have no USB cables that can carry more than 1A of current! That means all the money I spent on 2A chargers is useless! In fact, the majority of the cables I have suck. Here’s what I found:

  • Most Chinese cables (3ft) provide ~0.4A
  • Long cables provide significantly worse current. I think they are 3M long (so 9-10ft) and they provide only ~0.2A
  • Some Chinese cables basically provide NO current (0.02A?). Devices still seem to charge on them though
  • Some cables for devices that I didn’t buy from China also provide less than 0.5A. You don’t always get what you pay for
  • The better cables are from recent phones bought in North America. However, they still vary a lot from 0.8A – 1A
  • Short cables (~10cm) from China do pretty well. They get 1A
  • Apparently 28/24 gauge cables are better, but you can’t seem to buy them from China (or at least those specs aren’t advertised). I bought some from Monoprice and will have to run some tests when I get them to see whether they can carry 2A

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