A fountain cartridge battery vape is a small, replaceable component filled with liquid ink designed to fit into the pen barrel. Here are some functions and considerations for using fountain cartridge battery vape:

1. Ink Supply: The primary function of a cartridge is to supply ink to the fountain pen, allowing for smooth writing. When inserted correctly, ink flows from the cartridge through the pen's feed to the nib.

2. Convenience: Cartridges are user-friendly and convenient, especially for beginners or those who prefer not to deal with filling pens from ink bottles. They are easy to install, replace, and typically don't create a mess.

3. Portability: The portability of cartridges is a significant advantage, as you can carry extra cartridges for quick changes without worrying about spilling ink.

4. Variety: There are various types of ink cartridges, including proprietary cartridges designed for specific pen brands and standard international cartridges that are more broadly compatible.

5. Color and Consistency: The color and consistency of the ink can impact the writing experience. Cartridges are available in a range of colors, from traditional black and blue to more vibrant and unique shades.

6. Ink Types: Different ink types are available in cartridges, such as dye-based inks, pigment-based inks, iron-gall inks, bulletproof inks, shimmer inks, and scented inks, each with its own characteristics and uses.

7. Maintenance: Proper maintenance of cartridges and the fountain pen is essential for optimal performance. This includes cleaning the pen regularly to prevent clogging and ensuring the cartridge is correctly inserted to avoid leaks.

8. Storage: Storing your fountain cartridge battery vape properly can extend their lifespan. It's recommended to store the pen with the nib pointed upwards and to remove the cartridge if the pen will not be used for an extended period.

9. Compatibility: Not all cartridges fit all fountain pens, so it's important to ensure the cartridge is compatible with your pen model. Some brands, like Pilot, Lamy, and Parker, have proprietary cartridges, while others may use standard international cartridges.

10. Economical Consideration: Cartridges may be less economical in the long run compared to bottled ink, as they cost more per milliliter of ink.

When choosing a cartridge, consider factors like the type of cartridge battery vape you have, drying time, waterproofness, and color saturation. Proper care and maintenance, as well as understanding compatibility issues, are crucial for a positive fountain pen experience.