Answered by Shaykh Faraz Rabbani
I woke up yesterday and the time for sehri had past and there was about 45 minutes left for fajr, would my fast be accepted because I made my intention after the time for sehri had past?

Walaikum assalam,
As for the intention in fasting, you can make the intention to fast anytime until the Islamic mid-day, which is half-way between the time fajr comes in and when maghrib comes in. [Around an hour before Zuhr.] An intention may be made any time from Maghrib of the night before, and remains valid as long as you did not resolve NOT to fast.
Note, however, that an “intention” [go back and read the posting on Intention] is “a firm resolve to perform an act of worship,” and, as such, it is rarely conceivable that a Muslim NOT have an intention in Ramadan, the scholars tell us. And even the intention to get up for Suhur is considered sufficient for validity.
And Allah knows best.
Wassalam,
Faraz