* May take several quarters to repay TARP

* Says morale "pretty good" at Merrill

* Shares rise (Adds comment from activist investor, updates share price)

By Elinor Comlay and Jonathan Stempel

NEW YORK, April 2 (Reuters) - Bank of America Corp (BAC.N: Quote, Profile, Research) Chairman and Chief Executive Kenneth Lewis said it may take several quarters for the bank to repay its $45 billion of federal bailout money, although he believes the U.S. economy may bottom out in the second half of this year.

"We're at a point where you're seeing mixed signals, just small mixed signals, some housing sales a little better than you'd think, or some car sales not being quite as bad as you'd think," Lewis said on CNBC television on Thursday. "It signals that you're getting close to the bottom."

Lewis, who turns 62 next week, spoke ahead of one of the most critical months in his eight years leading what is now the largest U.S. bank.

Charlotte, North Carolina-based Bank of America is expected to release first-quarter results on April 20. At its annual meeting nine days later, Lewis will face angry shareholders calling for his ouster in light of the bank's sinking share price and its troubled acquisition of Merrill Lynch & Co.

"It's good he's out talking," said Jonathan Finger, who with his father runs Finger Interests, a shareholder seeking to replace Lewis as chairman and supplant two other directors. "We want a board that is more critical in evaluating what management wants to do."