Wish I knew what went wrong. I thought it might be the battery, since the car's been sitting in the heat w/ very little driving lately. But it was clearly the alternator.
In the past year, I've changed the battery, added a new head unit/camera, no new amps. Can't imagine that made a difference. Did the drive belt, timing belt, etc. a couple of months ago. I'd like this to be the last alternator