The phones will charge on the charging pad, they are just too large to seat themselves in the proper spot with a case on them. I have a 2016 with the Qi pad, and it worked fine with my S7Edge and also works for my S8+. I'll try to get you a pic this evening when I leave the office.
If you angle the top bezel of the phone at downward angle with the top bezel pointing toward the front of the truck, with the bottom bezel raised outside of the pad, the phone will not slip, and it will also charge flawlessly. But, since the Qi pads aren't fast charging, I'd recommend getting you a fast travel charger and use your AC/DC jack that should also be built into your center console. I only use the wireless charger if I don' need some juice quickly. I forgot what the output rating of the pads are, but it's not very high.
I hope that makes sense.