Compatible charger? Meaning what? How do you know? Well, not you, how would those less steeped in the way of the electron know? Those who thought all USB chargers were alike in their charging rate (if it's even rate we're talking about?).
To charge a QC3 compatible thing (phone, powerbank, whatever) at QC3 speeds
[1], you need a QC3 capable charger. There's also Power Delivery (PD), because The Great Thing About Standards™ applies. There are logos to befuddle the user and, particularly in the case of phones and fondleslabs, proprietary branding for the technology (eg. Motorola Turbopower is just another name for QC3).
There are also powerbanks that can charge at normal
[2] USB voltage and current from more than one USB plug at the same time, which is a nasty but potentially useful bodge (if you have a high-power multi-output charger), and others that take the easy (for the designer) option and charge from some non-USB-compatible wall-wart via a traditional DC jack. Works fine, but less ideal for touring, as you can't then use the same wall-wart to power your other USB stuff, or obtain an appropriate wall-wart for the sockets used by
FOREIGNS in
ABROAD, rather than mucking about with adaptors.
Also note that just because a powerbank supports QC3 or PD on an output, doesn't mean it does so on the input. For a typical touring cyclist, the speed at which your phone can charge from your powerbank is largely irrelevant; the important thing is how fast the powerbank can charge during your cafe stop.
When I tried to buy one (some time ago now), QC3 compatible mains chargers in a folding BS1363 form-factor were surprisingly hard to come by. I ended up with an expensive Sony one in order to get a slidy-inny earth pin. The situation may have improved.
[1] Both QCn and PD work by having enough intelligence at both ends to enable the device to negotiate with the charger to raise the voltage above the normal USB spec, delivering more power and reducing cable losses.
[2] For arbitrary values of normal.