Is it possible to parallel two HID ballast?

[XeRay]

They must be DC output ballasts for this to work, no way they are exactly synchronized if the were at 400 Hz or other AC frequency.

 

[dan13l]

They must be DC output ballasts for this to work, no way they are exactly synchronized if the were at 400 Hz or other AC frequency.

I'm probably in the wrong forum but I have 35w morimoto ballast connected to my car, I wanted to test out a 55w morimito ballast that I have. I accidentally connected the 55w plugs that go to the bulbs into the plugs of the 35w ballast by mistake thinking they were the bulb plugs. I turned on the lights but quickly turned them off when I noticed the one bulb didnt turn on. After, I checked both ballast and they both worked fine. What kind of damage would I have caused? They may work now but how about down the road?

 

[broadgage]

It depends on the type of ballast.
Electronic ballasts can not be parraleled for various reasons.

The old type of copper/iron ballasts most certainly CAN be parralled, indeed some high power discharge lamp circuits are intended to consist of two ballasts wired in parralel. This is common practice for very large discharge lamps that are not used in large numbers. It is much cheaper and simpler to to use a couple of "off the shelf" ballasts than to custom manufacture small numbers of specials.

As the O/P refers to 2 ballasts, one lamp, and ONE IGNITOR, that suggests that old type copper iron ballasts are being considered since most types of electronic ballast do not use a seperate ignitor.

A pair of 35 watt copper/iron ballasts in parralel WILL work a single 70 watt lamp at ABOUT the correct power input. Lamp operation may be non optimum though, because it assumes that a 70 watt lamp operates at exactly the SAME voltage and exactly TWICE the current of a 35 watt lamp.
This is not the case, but the difference is small and the lamp will work at least reasonably, but light output, life, colour rendering, or efficiency may be poorer than intended.

Take great care if experimenting with HID lamps and circuits, not only is line voltage potentialy fatal, but the high starting voltage is even more dangerous.
HID lamps can burst or shatter with great violence even if operated correctly. The risk is potentialy increased by operation otherwise than as instructed by the manufacturers.

 

[XeRay]

It depends on the type of ballast. Electronic ballasts can not be paralleled for various reasons.
As the O/P refers to 2 ballasts, one lamp, and ONE IGNITOR, that suggests that old type copper iron ballasts are being considered since most types of electronic ballast do not use a seperate ignitor.

Automotive ballasts (he is asking about) are electronic ballasts. The vast majority of modern automotive ballasts in fact do have the igniter seperated from the ballast. The igniter is either attached to the bulb or very close to the bulb.