My induction cooktop doesn't (always) detect the big diameters. It heats only the center of my frying pans, but works with the big saucepans, even though they have the same Ø :
Hidove 1800W Electric Hot Plate, Countertop Stove Double Burner for Cooking, Infrared Ceramic Hot Plates Double Cooktop, Silver, Brushed Stainless Steel Easy To Clean Upgraded Version - Walmart.com