Running Headlight Bulbs at Less than 12 Volts? Options

[Coomer]

Hello,
I'm currently working on a project where I'm re-running all of the power wires to my headlights and using relays in order to make the headlights brighter, and I got to thinking that it'd be really cool to have my high beams light up partially when just my low beams are on, and fully light up when the high beam switch is engaged. In order to do this, I'd need to supply less than twelve volts to the high beam bulbs when just my low beams are on, which I could easily do through the use of relays and some tricks to reduce voltage to a suitable level.

I'm just curious as to whether or not it's bad for headlight bulbs to run at less than twelve volts. I know that up in Canada the high beam bulbs are on, but not at full power when the DRLs are on, so this leads me to think that it wouldn't be bad for the bulbs. Also, in my friend's SPW catalog, they had a device to reduce headlight brightness with a knob, and I'm guessing that it just reduces voltage to the light bulbs. I just want to be sure, so does anyone know if it's bad for 9005 headlight bulbs to run at a level that's less than twelve volts. I'm just randomly guessing that I'll want them to run at around eight volts. Thanks in advance for any help you guys can give me.

By the way, if this all works out well, I'm going to write up a nice how-to to do this.