Lithium-ion batteries have a limited lifespan and are affected by a number of factors: environment, storage, number of charge/discharge cycles, and degree of discharge/charge.

To extend battery life and battery life, we recommend following these simple principles:
1. Avoid high temperature and humidity:
- The optimal operating temperature for the battery design is room temperature.
-High temperature can shorten the life of Li-ion battery.
- Avoid high humidity environments.
-It is best to keep the handheld/graphing calculator in a cool, dry place as close to room temperature as possible.

2. Using and charging:
-As lithium-ion batteries age, the capacity of the battery decreases.
With proper maintenance and normal use, the battery will last approximately 3 years.
- If the handheld/graphing calculator is used frequently, the battery should be charged frequently. Don't wait until the battery is completely depleted before charging.
- If the handheld/graphing calculator is not used frequently, the battery should be fully charged at least once a month.
-Do not leave the handheld/graphing calculator connected to the charging device for more than 3 days.
- Use only rechargeable lithium-ion batteries designated for use with handheld devices/graphing calculators.
- Use only charging devices designated for handheld devices/graphing calculators.
- Fully charge the handheld/graphing calculator before testing.

3. Recommendations for storing handheld devices/graphing calculators containing lithium-ion batteries for 3 months or longer:
-The optimal temperature for proper care and storage of Li-ion batteries is 0–25° C/32–~77°F.
- Prolonged storage can result in deep battery discharge, which may degrade Li-Ion batteries and reduce battery capacity, service life and rechargeability.
Therefore, it is recommended to fully charge the battery before storing the handheld device for extended periods of time, and every three months during storage.

4. Update the operating system of the handheld device in time:
When there is a new version of the handheld device/graphing calculator operating system, please update it in time. New operating systems may contain new programs to optimize battery life.