First of all, distinguish whether the two ends of the split ring are USB interfaces and whether USB interfaces are inserted.
(It is recommended to pull both sides. Have you ever seen someone insert the SN code into a computer? )
Generally, the safest way is to plug it into the USB of the computer, because the current is relatively stable and the bracelet will not be damaged due to charging.
If there is a problem with computer charging, you can consider using a mobile phone charging treasure. Insert the charging treasure directly, and restart the bracelet with high current to complete charging.
If it can't be fully charged for a long time, it may be the cause of poor contact. You can use your own eraser to erase the USB interface of the bracelet.