Magic Mouse batteries are designed to last for several years under normal use, typically 3-5 years, though the lifespan can vary depending on how often and intensively the mouse is used. Given your mouse is approaching 3 years old, it’s possible the battery's health has started to decline.
Some reasons why charging the mouse may be slow:
- Lithium-ion batteries degrade over time, leading to slower charging and reduced capacity.
- If the Lightning cable or USB charger isn't working optimally, it may be charging the mouse at a reduced rate.
- Dust or debris in the Lightning port on the mouse could interfere with charging efficiency.
Unfortunately, the Magic Mouse does not have a user-replaceable battery. The battery is integrated and sealed inside the device. AFAIK, Apple does not offer battery replacement services for the Magic Mouse; instead, they recommend replacing the mouse if the battery is no longer functioning properly.
A few things you can still try:
- Try both a known good charging cable and power adapter.
- Inspect and gently clean the port with a non-conductive tool, such as a wooden or plastic toothpick, to remove any debris.
- Resetting the mouse.
