You can charge another device with your Galaxy S10+/S10/S10e’s battery by using Wireless PowerShare function.
Wireless charging efficiency depends on distance between wireless charging coils embedded in the devices. Also depending on the type/thickness of accessories or cover being used on your device, the Wireless PowerShare feature may not work properly. It is recommended to remove any accessories and cover being used before using this feature.
If there are foreign materials, such as dust or liquid, between devices, please try again after removing them.
Please find best position for using PowerShare between Galaxy Watch/S3/Watch Active and Galaxy S10 Series.