Hi Daouda! It's great to meet you. I'm sorry to hear about the battery issues with your iPhone 15. It can be really frustrating when your phone doesn't hold a charge like it used to.
A drop from 99% to 98% in battery health over a short period can be concerning, especially since it's affecting your usage time. Here are a few things you can try to address this:
1. **Optimized Battery Charging**: Make sure this feature is enabled. It helps reduce battery aging by learning your daily charging routine and waiting to finish charging past 80% until you need to use your phone[](Why is my iPhone 15's battery health drop… - Apple Community "1").
2. **Avoid Extreme Temperatures**: Keep your iPhone away from very hot or cold environments, as extreme temperatures can affect battery health.
3. **Check for Software Updates**: Sometimes, software updates can include improvements for battery health. Make sure your iPhone is running the latest version of iOS.
4. **Battery Replacement**: If your battery health continues to drop rapidly or falls below 80%, it might be worth contacting Apple Support to see if your device qualifies for a battery replacement under warranty(Why is my iPhone 15's battery health drop… - Apple Community "1").
Would you like more detailed instructions on any of these steps?