The devices I bought came through a few days ago and I have been using them quite a bit since then. This is the vendor and product :
http://www.aliexpress.com/item/New-Hot- ... 71989.html
So far I have found them to be incredible. They are extremely useful and enable you to discover what is really going on. Some examples are :
* How much current can be pulled out of a laptopn USB port. I had no idea that my laptop could provide nearly 1 Amp to charge a tablet. Nor did I know my tablet would pull that amount of current.
* How much current can be pulled from USB chargers. Chargers will state what they are rated at, but with these you can see what is actually going on, and how much of a voltage drop there is for devices trying to pull higher currents.
* How much current a USB hub only (without any devices attached) pulls.
* With the Joggler, how much current drawn can fluctuate for devices, I thought, would pull pretty much the same current most of the time. I don't know why this happens. Also, when adding additional USB devices, why the current drawn increases initially, then returns to the amount prior to being added. I don't understand this yet, but have some theories.
* How much current, various devices actually pull. I'm please to see that some webcams, I have tried, only draw 0.07A.
* When your device is lying to you about being fully charged. When a device is fully charged it should only draw a negligible current, if any. A motorola phone I use, states it is fully charged, but is still drawing 0.11A. So, I leave it till the current drawn drops to a negligible amount, and then I know it is really fully charged. I think that the charge status may be determined by the voltage of the battery or some other point.
So overall, to me now, this device is invaluable, and I have only just started to use it. However, I think that the device may draw more than a negligible amount of current to operate. When I put 2 devices together, the first device reported that the current drawn was 0.04A and the second reported 0.00A. So now I'm in the situation that I need to test the device and consequently need to have some sort of a USB breakout cable and a multimeter. This would be useful to do, as I'd like to know. But I still think that these devices are extremely useful in many ways. I need to test how much, if any, they affect data throughput. Gut feeling, is not that much, as they look well made. And so far, I have not noticed any detrimental side-effects of using them with devices that data would be passing through them - flash drives, sound cards etc.
I have yet to use them for the purpose I discussed here. But I am confident, that to see how much current is being drawn by USB devices attached to a Joggler, they will perform admirably. In addition, they fit quite nicely on the side of the Joggler.
The price of them is now $1.70 from the vendor above, and if you search aliexpress, there is another vendor offering them for $1.69, postage included. Peanuts for an extremely useful device.
will report back