Both the lithium batteries of pad and Mac are relatively large. If the heating and cooling area is large, the battery is more sensitive, and the suitable charging temperature is 10~35 degrees Celsius. The lithium battery of iPhone is relatively small, and the charging temperature range is wide, ranging from 0 to 35 degrees Celsius. In winter, the indoor temperature is generally not lower than 0 degrees Celsius, and the mobile phone can be charged normally. ""It's too cold in winter, so you'd better wrap a quilt. It's too hot in summer, so you'd better blow air conditioning. "This is Apple's solution for devices that don't charge properly.