Brad and his wife both have iPhones and they shut down with 15% left. What gives? Leo says it's a software thing. In essence, the phone is making a guess and as a phone gets older, it has less capacity. So that estimate can get more inaccurate the older the phone gets. Batteries can be recharged about 500 times, and as it gets closer to that number, it gets more inaccurate. Brad doesn't want to buy a new phone, though, and Leo says he doesn't have to. He can go into Apple and request they replace the battery. It's about $100. Can he do it himself? Leo says maybe. He should try going to iFixit.com. They have videos that will show him how to do it, and they also have the tools and parts. But it's not for the faint of heart. iFixIt will also give him a repairability score to let him know if it can be done.
The chatroom says that there is a recall underway for unexpected shutdowns.