The duration a 3000mAh battery will last on a smartphone can vary based on several factors, including the smartphone’s hardware, software optimizations, screen brightness, usage patterns, and network conditions. As a general estimate:

1. Light Usage: With minimal use, such as occasional calls, texts and light web browsing, a smartphone with a 3000mAh battery can last around 12 hours on a single charge.

2. Moderate Usage: For moderate use, which includes social media, occasional video streaming, and general app usage, you can typically expect the battery to last approximately 8-10 hours.

3. Heavy Usage: If you’re using your smartphone intensively for activities like gaming, continuous video streaming, or frequent GPS navigation, the battery might last around 4-6 hours.

4. Screen-On Time: The screen-on time is a crucial factor. If the screen is continuously active at high brightness, even a 3000mAh battery can deplete relatively quickly. Under continuous screen use, it may last around 4-6 hours, depending on the smartphone.

For a general-purpose smartphone that can perform a wide range of tasks and meet the demands of modern usage, it is advisable to choose a device with a significantly larger battery capacity to ensure you have enough power to get through the day without constant recharging. A 3000mAh battery would not be sufficient for the typical smartphone user’s needs.