Why isn’t the Xiaomi Focus Pen fully charged after being placed on the Xiaomi Pad 7’s magnetic area for a long time?

To prolong the battery life of the Xiaomi Focus Pen and prevent trickle charging, a smart charging strategy has been implemented. Once the Xiaomi Focus Pen is fully charged, charging stops. It will only resume when the battery level drops to around 80%, at which point it will recharge until full. As a result, even if the Xiaomi Focus Pen remains attached to the tablet for an extended period, it can not always be charged at 100% when removed.
However, an 80% charge provides approximately 80 hours of continuous writing, which is sufficient for extended use.
Note:
If you are concerned about battery levels, you can occasionally remove the Xiaomi Focus Pen and reattach it to initiate charging until full.