All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
There is no specific limit that confines voluntary fasting.
Continual fasting is when you fast every day without breaking the fast except on days when fasting is forbidden. Continuous fasting is not recommended according to the view of some scholars, such as Ibn Al-Qayyim who commented on the following Hadeeth, "The most beloved fasting to Allah is that of (Prophet) Daawood; he used to fast every other day," Ibn Al-Qayyim said, "It means that fasting a day and breaking the fast on the other day is better than fasting every day..." [End of quote]
Finally, we remind you, dear questioner, that a few regular good deeds are better than many irregular good deeds. In a Hadeeth reported by 'Aa'ishah the Prophet said: "The dearest deeds to Allah are those done on a regular basis even though they may be few." [Al-Bukhaari and Muslim]
Allah Knows best.