Your Windows 10 Mobile phone as a USB power source!

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Now, don't take the title too seriously, there are limitations here - not least that you usually want to preserve your phone's battery and not drain it. But I wanted to document that modern Windows 10 Mobile phones can act as a power source for accessories or anything small that charges via USB. With a special adapter!

So there I was playing with a new mobile toy - a pocket drone, out and about flying it at night in a park while waiting for family, and the drone exhausted its battery. I had the drone's tiny charging cable with me, ending in a standard USB jack, but I didn't have a power bank with me. 

What I did have was my Lumia 950 XL though - if only there was a way to transfer some of its big battery charge into my drone, to charge it up again.


And it turned out that there was. And I already had the right adapter, albeit at home. So I started experimenting. I'm sure many of you have played with plugging in USB (powered) hard disks, USB sticks, and the like already, so there's nothing really new here other than widening the parameters of the hardware involved.

The key here, of course, is the little USB-A-female-to-USB-C-male adapter (£5 on Amazon UK for two) shown in these photos. Plus a willingness of the Lumia to act properly with the USB Type C connector and bus, in terms of handling bi-directional power transfer.

So I plugged in my pocket drone and... it started charging happily (shown above).

What else could I charge from my phone, that wasn't too demanding in terms of power - after all, there has to be a limit in terms of current supply and I really didn't want to play with anything that drained the phone too fast? My Fitbit One is always with me, in my pocket, and needs charging about once a week, but why couldn't this small weekly charge be handled in my pockets from my phone, rather than plugging it into a wall and then forgetting to pick it up again?


The Fitbit One also charged perfectly. What else could I try? Rummaging through my drawers, I found a USB LED lamp - I plugged this in and it too worked perfectly:


And it's at this point that I'd suggest that quite a few other USB accessories will work fine too - fans spring to mind on a hot day? What about you? Anything interesting that you've powered or charged from a USB Type C port on a Windows phone?

I did wonder what sort of current the phone could supply and, while I didn't want to push the limits too hard (I did try a USB floppy disk drive, but this failed to mount after initially buzzing the drive's motors!) I did try inserting a current meter in the line while charging the drone:


So just under 0.3A supplied, which is not bad at all - a traditional USB port on a PC supplies 0.5A (though higher current ports now exist). It's not clear whether this was limited by the drone's input or by the phone, so - again - data points welcome.

In short, by carrying around the little USB C-to-female USB A adapter, my Lumia is ready to give up a bit of its charge to help another pocketable gadget. What about you, have you tried anything similar that's of interest?(!)

PS. For more on that fun little micro-drone, I did a full review here.