New Alternator now idling rough

[Rutherford]

I installed a new alternator today. The bearings had been bad on the old one for awhile and I final figured out that's what was making the strange noise. Anyway got a Bosch alternator from NAPA, installed it, no big issues but now the car idles rough. When I give it gas it sounds fine. When I first cranked it up it sounded OK. I let it run after I first cranked it up for awhile with the headlights on. Turned it off and after that it started idling rough. I rechecked the connections on the battery and alternator. I checked the belt. It seems to crank fine but idles rough. So what's up? If the alternator is not charging the battery would it do this? How can I check the alternator? Need to get to work Monday...any help would be greatly appreciated.