Low voltage going to headlight…

I was measuring voltage at the fuse box today. I’m measuring 12+ volts at most fuses in the fuse box. With headlights switched on - voltage at the fuse for the headlights is around 8V when engine is off and approximately 10V when the engine is running. I didn’t check this voltage before I installed the new headlights - but I did just swap out standard headlights for halogen headlights. I detect no malfunction - but the low voltage concerns me. I recently made extensive efforts to clean contacts throughout the wiring system. Poor connections would, otherwise, be my first place to check.

Am I correct that the voltage at the fuse box should be 12V+ when the lights are on and the engine is running?