The thing is, some cars will work without using relays, but MOST wont. The wiring in our GN is aging in a big way, and picking up resistance along the way. The "startup" demand for the HID ballasts puts us in the relay-needed category. Otherwise, the HID's use less current than the standard halogen bulbs. It's that startup that gets you. Low battery, high surge, and the bulbs just flicker instead of coming on.
The startup on a typical ballast lasts around 50-200 milliseconds, just enough for the power sag to prevent the lamps from striking the arc. Now, if the bulb doesn't start, there is an internal spark gap in the ballast that absorbs the high voltage energy (at least there is in the Philips boxes). Problem is, the spark gap doesn't last very long, eventually allowing the high energy to self-destruct the low voltage internal components. Then you have a melt-down. So, strong voltage at startup is absolutely necessary.
If you ever see your headlights start to flicker, it's telling you that you need relays. But usually by then it's too late.
The startup on a typical ballast lasts around 50-200 milliseconds, just enough for the power sag to prevent the lamps from striking the arc. Now, if the bulb doesn't start, there is an internal spark gap in the ballast that absorbs the high voltage energy (at least there is in the Philips boxes). Problem is, the spark gap doesn't last very long, eventually allowing the high energy to self-destruct the low voltage internal components. Then you have a melt-down. So, strong voltage at startup is absolutely necessary.
If you ever see your headlights start to flicker, it's telling you that you need relays. But usually by then it's too late.