OK, mostly solved. I went to the Genius Bar today, and the guy is like, "do you always have all those tabs open? That could cause your power problem." And I'm like, "yeah right, I've always got tons of tabs open". Sounded like an Apple excuse.
But he runs the Activity meter, and then shows me the amp usage under power, and turns out all these open tabs using shockwave are sucking electricity constantly. Took awhile to understand, but I had two browsers with dozens of tabls open, and that what doing it. At least doubled or tripled the remaining hours.
So it's real important not to have all those tabs open. So I'm looking into better ways to manage my news reading that having tons of tabs open. I wish I'd know this long ago, as the battery on my black MacBook is probably OK after all.