With the iPhone 8 and 8+, Apple has added fast charging, just like they recently did to the 10.5 and 12.9 iPad Pros. Fast charging requires a USB-C wall charger that provides USB PD (Power Delivery) and a USB to lightning cable that does as well. I have the USB C to lightning that Apple sells for way too much money, because it’s one that I know will work, and a 29w power brick that I bought on EBay.
We start at 9:30pm CST with 28% battery. I took this literally the second I plugged it in.
Half an hour later, we are at 75% for a gain of 47% in 30 minutes. Since fast charging works best from zero, tapers off a bit as the battery gets closer to full, and then basically drops to 10-12w over 80%, I would say this is right in line with Apple’s claim of “50% in 30 minutes”
The cost of entry is pretty steep, but can be mitigated a bit by buying the power brick on eBay or finding one on amazon that supports USB-C PD, but for me it’s totally worth it since BOTH of my daily carry devices (IPhone 8+ and IPad Pro 10.5) support fast charging with this setup. I wouldn’t bother having one at home, but I’m going to carry this around in my messenger bag, so when I really need to top off one of my devices I can do it very quickly.