Nissan Altima shuts off and won't start, low batt voltage

I've got a 2001 Altima that shut off while driving.
Engine doesn't try to turn, just flickering dash lights
when you try to start it.

The battery is only about a year old, but it is a
factory 2nd. I just measured it after being parked a
while and got around 11.8v. I jumped it and
checked voltage again a few times while the car
was running. With no lights or anything turned on
and the engine running the battery slowly dropped
to 11.6v before I shut it off.

That's as far as I've gotten. Just before making this
post I read a out the trick of pulling off the neg
cable while the car is running to check the
alternator, so I can give that a go later. I've also
been told it could possibly be the cam sensor. Any
suggestions or troubleshooting I should try?
Thanks!