Dodge Ram 2015 Headlight Issue

For context, My stock headlights had broken seals in them so I replaced them. I bought brand new ones and they work fine, however, while inside the vehicle and reading the battery voltage (normally steady at 14) it flickers from 14 to 15. Yesterday, the left bulb wasn't working, the markers and blinkers, and high beams worked fine. but when I went into the cab and read the voltage it said 13. I decided to fix it the next day, when I came back the next time to fix it, the headlight worked at the voltage started flickering between 14 and 15 again. Is there any reason why this might be happening? Are the headlights drawing too much power? I've noticed that the white marker lights have a small flicker to them. I would show a video but it happens randomly