Alright all you car guys, now you get to rip into a newbie... So here is the mistake I made. The other day I replaced my radiator. All went well, except that since I was rushed, I forgot to unplug the battery....I hope to god I didn't do anything too severe to the system. Ever since then, I when I start up the car, the battery meter is very low, but soon comes up to normal(around the middle of the gauge). Do you think that I might have fried the alternator?

 

Radiator change out shouldn't have any effect on battery. Auto parts store will check your battery for free. Could be bad battery or alternator is not charging.

 

Bad ground or poor battery connection. If the battery is serviceable, check the electrolyte level. If it is low, make your own and top it off. Make your own battery electrolyte with 1/2 cup epsom salts & 1/2 gallon DISTILLED water. mix completely & add as needed.

 

Double check the grounds at the frame and the fender. Maybe on radiator support. I agree that radiato has nothing to do with battery so that should not be an issue...unless the ground fell of or was removed....Double check ground by PS pump also.