There is a physical feature of a normal USB-C port to charge a device which will have the Anker battery to drain the power from the device to be charged during the charging process. This situation mainly refers to the usb-c devices and batteries. Please disconnect your USB-C device once it is fully charged. This will prevent the device from returning the charge to PowerCore.
Currently, we have the A1371 that will have such returning charging issue. When you use the A1371 to charge laptops such as macbook 2015 and usb-c phones, the device will return charge to A1371 if it is unplugged when charging is completed.
As for A1275 and A1375, currently we do not hear return charging issues from our customers as these power delivery batteries have better compatibility with usb-c devices.
The storage temperature of our battery is -20°C to 60°C while the surrounding temperature limitation when using the battery is recommended at 0°C to 45°C. The battery itself cannot be over 54°C.