Battery light
 

I have an 06 mazda3 gt and when ever i put the car in reverse the light comes on then when i go in to drive it blinks then goes off. Also if im to low in rpm it comes on till i start driving alil faster. Could this be the battery or alternator? Or or could there be an easier fix?

probably a corroded connection on the alternator, maybe in the power plug to it...
Or the alternator has an internal problem and can't provide enough current.
Or possibly there is a short somewhere drawing enough current to overload the alternator, dropping the overall voltage.

Thanks ill try that out see where it gets me and just hope for the best