One other option is available.
I have the Anker 26800 battery pack that has a Fast Charge feature.
If you press the button on the battery pack, it will go into Fast Charge mode.
somehow, Anker has been able to get this thing to talk to the charger/regulator on the phones.
it has worked on every phone and Kindle device I have plugged it into.
My Note 4 goes from 15% to full 100% in about 20 minutes.
The Kindle Paperwhite eReader is fully charged in something less than 30 minutes.
that is quite unlike the OEM charger taking hours to charge it up.