Maybe... I have Joule.ipa on my iPhone 6 and iPad Pro 9.7. I recently did a 9-hour cook making Char Siu. I kept an eye on things with my iPad Pro, but also had the app open on my iPhone 6 when I was out of the house or in another room. Most of the time I never LOOKED at my iPhone. However, that night when I finished the cook and was quitting all the apps on both devices, I noted that my iPhone battery had dropped from about 85% in the morning to under 19% that night. Not so much the iPad Pro.
Anyone else noting heavy battery impact on their iPhone or Android phones over long cooks???