My car starts strong, I can turn on the high beams, radio, brake lights, etc when sitting in the driveway. When I pull out of my driveway and start driving, the voltage meter jumps to “L” and then goes to a little over the middle, back and forth when I’m driving. I can’t really drive it anywhere because when the voltage is low the blinkers don’t work and the lights don’t work either (Super Dim). I’m 16 with not a lot of electrical knowledge. I don’t really want to take it to a shop so anyone who can help please do. Much appreciated.