I really like the fact that the USB Tester has the little OLD display. It gives more information than just seeing the current current consumption, The USB Tester worked perfectly for a bug I was investigating (current draw increased by 8mA when turning on the DMA clocks). It just worked. Plug everything together and awy you go. Its a keeper.
Great little tool. Get one now, even you don't need it yet, before you find yourself in need of measuring USB current or voltage, with an USB cable in one hand and a knife in the other (real mess, you don't want that, trust me). I'm not exactly in love with the oversized-vias-as-poor-man's-banana-sockets, though. Would gladly pay $2 more for proper banana jacks and wouldn't mind it being a tad larger because of that.
This works great for testing USB charging. The only issue I've seen is that it adds enough resistance to the power lines to cause my Galaxy S4 to not go to full 1.9A mode. The UI is great and it works very well otherwise.
Response from FriedCircuits | Jan. 19, 2015
Thank you. I have been increasing trace width to help with that. But the thing that helps the most is to get the shortest USB cable you can. We sell 3ft cables but I thinking maybe I should stock some 1ft cables. If yours shows the firmware version on boot up you have the latest. Otherwise check http://friedcircuits.us/docs to update to the latest.
Just receive mine. It's really nice bit of kit. Of course you can buy similar on ebay from China but most of them are garbage. Build quality and the display in this one are great. Soon I would like to check its accuracy, hope it will be ok.
Response from FriedCircuits | Nov. 18, 2014
Thanks. Yours also has the latest firmware with the new bar graphs and cleaned up interface. The measurements are done by the Ti INA219B. Should be a link to the datasheet in the product listing of the backpack.