Up until a few weeks ago, I was using an iPhone 5c for almost two years. I had it connected to a Wahoo Tickr HRM and a Wahoo speed/cadence sensor. I also use a Wahoo RFLKT to view the ride data so I don't have to keep the phone's screen on to see the data. With the 5c, I was using about 10% battery life per hour. I recently upgraded to the iPhone 6SE using the same configuration and, so far, I'm using less than 5% per hour. I'm running Cyclemeter as the app and since I started using my phone, I've not had had many issues with dropping connections. Occasionally, I get a dropped connection when the battery to the RFLKT or one of the sensors is low, because there are no warnings on the sensors and the RFLKT doesn't always display the low battery warning. Cyclemeter shows the % of battery life left on the sensors and the RFLKT but I don't always check.