The meanings are exactly the same, as Maven said, since I'd is a contraction for I would (or I had), and I've is a contraction for I have.
The contractions are used in casual speech, or in writing when on wants to convey an informal tone. The uncontracted versions are used in formal writing or less casual types of writing, such as a business letter, memo to one's boss, etc.
By the way, and as mentionned by Sam, I would not that to emphasis a past verb we use the auxiliary Do. exemple: I did manage. we could say simply without emphasis: '' I managed''.