BCAA is basically protein. Taking too much won't hurt you or anything like that. It'll just be a waste of money. Don't think that BCAA are calorie free.
BCAA have 4 calories per gram. It's a marketing loop hole that allows the companies to say it's calorie free. The FDA does not require companies to label amino acids as having calories but make no mistake, amino acids have the same calories as protein - 4 calories/gram.
Protein and amino acids are basically the same thing. Protein is long strings of amino acids linked together by poly peptide chains. When you eat protein, your body digests the poly peptide chains into individual amino acids.
If anything, amino acids will have more calories then protein because no digestion is required and they are 100% absorbed.
I would take one serving of BCAA before and after each workout/cardio session. Any more then that isn't needed and will just be a waste of money.