Hello. I got the Xiomi 10400 external power source directly from China -sent to me without postal charges.
I have an HTC cell phone where you cannot change batteries so you have to pay attention that you leave the house in full charge. And of course the a6000 runs dry in just a couple of hours.
The XIOMI seems to put in quite a current as the camera was fully charged in two hours.
Nice and warm!
A handy little gadget, not expensive at 41 dollars, either.