Factory HID question

[ghost rider]

When I turn my head lights on they go less bright after a second or so. Is this common for HID’s does anybody else experience this?

 

[The Car Stereo Company]

the initial surge in turn on power could cause the lights to be bright at first, but they will dim and get brighter as the bulb and ballast warm up.

 

[ghost rider]

Thanks for the reply, I have not done that much night driving but I always noticed the difference when I did turn the lights on.

 

[BAJASVT]

Unlike traditional halogen headlight bulbs that use a filament as the light source, HID lamps use an arc gap with no physical connection between the electrodes. The amount of current (amps) to initially jump the arc and start the bulb is greater than the amount of current required to sustain the illumination. What you're noticing is the slight overrun of the starting current before the ballast circuitry takes over and regulates the arc current.

Note: HID lamps are negative impedance devices which means that their current will continue to increase until they fail unless the current is controlled by a ballast. If you ever replace a HID bulb and it immediately burns out after it initially lights up, you most likely have a bad ballast.

 

[ghost rider]

Good info thanks BAJASVT.