{"id":41164,"date":"2019-12-13T09:53:23","date_gmt":"2019-12-13T13:53:23","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=41164"},"modified":"2019-12-18T10:56:36","modified_gmt":"2019-12-18T14:56:36","slug":"usb-charging-cubes-and-cables-bills-tests-prove-that-not-all-are-created-equal","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2019\/12\/usb-charging-cubes-and-cables-bills-tests-prove-that-not-all-are-created-equal\/","title":{"rendered":"USB Charging Cubes and Cables: Bill’s tests prove that not all are created equal"},"content":{"rendered":"

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Many thanks to\u00a0SWLing Post<\/em> contributor, Bill Hemphill (WD9EQD), who shares the following guest post:<\/strong><\/p>\n

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Power Cubes and USB Cables Multiply Like Rabbits<\/b><\/h2>\n

by Bill Hemphill (WD9EQD)<\/strong><\/p>\n

If your house is like mine, you have a box or drawer somewhere that has a tangle of 5V power cubes and cables.\u00a0 This is what one of my drawers looks like:<\/p>\n

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And yes I do have two<\/em> full drawers.<\/p>\n

Every new toy I receive comes with another cable and a power cube.\u00a0 With Christmas coming, we can all look forward to even more of them.<\/p>\n

But I have learned\u00a0 that not all power cubes or cables are created equally.\u00a0 Earlier this year I realized that sometimes my tablets would take forever to charge and other times they seemed to re-charge a lot faster.\u00a0 That got me wondering what was causing the difference. I found that switching power cubes or switching cables could make a difference.<\/p>\n

I decided to try some experiments.\u00a0 First I acquired a couple of Drok USB testers<\/a>.\u00a0 These are small, inline, digital USB voltage and amp testers.\u00a0 They clearly show the amp draw and the voltage being furnished to the device being charged.<\/p>\n

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Second step was to gather up my power cubes and test them against a device that would load the cube close to it rated capacity.\u00a0 I quickly found that ANY power cube I owned that was rated at less than 1 amp at 5 volt was not capable of providing anywhere near their rated capacity.\u00a0 Some would drop all the way down to 4.11V at 0.47A. So I made the decision to throw away ANY power cube that was rated at less than 1 amp at 5 volts. That trimmed down the total number.<\/p>\n

I proceeded to label each of the remaining power cubes from 1 to 10.\u00a0 Following is list of the cubes with their power rating:<\/p>\n

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Note:\u00a0<\/strong> Power cubes 8, 9 & 10 have two USB ports.\u00a0 I had purchased these so that I could charge two devices at once.\u00a0 I had also thought of using them to power two Raspberry PI computers.<\/p>\n

The following tablets were discharged down to less than 15% capacity:<\/p>\n