If you used the contraction "I've" for "I have", then most people would expect the present perfect. However, if you use "have" and the object follows immediately after, there is little chance of confusion.

"i've got" seems technically wrong i've got a box of books i have got a box of books <-- doesn't sound natural

"have" has the following functions : A) i) possess - eg: I have a new car ii) to receive - eg: I have bread and coffee for breakfast B) is also used to form the tense:- i) present perfect - eg: I have baked a cake for her For formal conversation, use "have" instead of "got".

I would agree with everyone's comments, "i have" is more formal and should be used in writing, but if you want to sound a bit more native, i'd recomend using "i've got" in everyday conversation (i personally say "i've got" a lot more).

Once again, I agree with Neal - to me they are interchangeable but it is DEFINITELY better to write "I have" especially in formal essays etc.