# Hazy deposits inside HID bulb...why???



## Fusion_m8 (Feb 8, 2011)

I got a T.I L35 about 4 months ago and only used the light occasionally. Recently I discovered some hazy brown deposits that have settled inside the bowl of the HID bulb. The output of the light _hasn't _diminished, however in the beam profile the hazy deposit does produce a darker spot when shown against a whitewall.



I've read about how HID bulbs do not like to be used as a strobe or be used for Morse-coding, thats why I ensure that when I use the L35, its on for a few minutes before its turned off. After turning off, I wait at least 5mins before turning it on again.



I contacted [email protected] where I got the light and he mentioned that this is normalconfused.



Is this true? If so, why is this happening? Any remedies besides having to change a new bulb?


----------



## 2filthy3 (Mar 27, 2011)

It is most likely solidified products of the capsule fill, such as mercury and sodium, when the lamp wall reaches operating temperature they evaporate and no longer obscure the light path.


----------



## curby (Mar 29, 2011)

So speaking of strobing HIDs, what parts of the system does it stress, and what parts may have their useful lifetimes decreased as a result of short powered durations? I'm considering getting a used HID with multiple former owners, and I want to know what possible hidden damage there may be. Thanks!


----------



## mvyrmnd (Mar 29, 2011)

This thread was another victim of The Great Crash.

To explain the OP, from Wikipedia:
"The tube is filled with both gas and metal salts. The gas facilitates the arc's initial strike. Once the arc is started, it heats and evaporates the metal salts forming a plasma, which greatly increases the intensity of light produced by the arc and reduces its power consumption."


To answer curby's question, from the same article:
"Factors of wear come mostly from on/off cycles versus the total on time. The highest wear occurs when the HID burner is ignited while still hot and before the metallic salts have recrystallized. At the end of life, many types of high-intensity discharge lamps exhibit a phenomenon known as _cycling_. These lamps can be started at a relatively low voltage. As they heat up during operation, however, the internal gas pressure within the arc tube rises and a higher voltage is required to maintain the arc discharge. As a lamp gets older, the voltage necessary to maintain the arc eventually rises to exceed the voltage provided by the electrical ballast. As the lamp heats to this point, the arc fails and the lamp goes out. Eventually, with the arc extinguished, the lamp cools down again, the gas pressure in the arc tube is reduced, and the ballast can once again cause the arc to strike. The effect of this is that the lamp glows for a while and then goes out, repeatedly."


----------



## curby (Mar 29, 2011)

Wow. So according to


> The highest wear occurs when the HID burner is ignited while still hot and before the metallic salts have recrystallized.



the most damaging part of quickly cycling the system is turning it off and back on before the bulb has fully cooled. I thought that turning it off before it's fully heated up is the biggest problem, and given a lot of comments in this subforum that seems to be a common misconception (assuming Wikipedia's right).

Just to fully beat this dead horse, consider two scenarios.

1) The light is accidentally turned on when it's bumped. Realizing this accidental activation, the user quickly turns the light off.
2) The light is being used but the user accidentally hits the power switch. To get light back as soon as possible, the user quickly turns the light back on.

According to Wikipedia, scenario 2 above is more taxing on the bulb. I had no idea. Thanks for the link!


----------



## mvyrmnd (Mar 29, 2011)

I think both scenarios have the potential to damage the bulb/ballast.

With my HID, I tend to wait a full minute between operating the switch, whichever way I'm turning it.


----------



## BVH (Mar 30, 2011)

According to Xeray, if the light is turned back on within a 1/2 second after having run 20 or 30 seconds and switched off, it is actually easy on the ballast and bulb. More than a few seconds off, results in lots of stress.


----------



## curby (Mar 30, 2011)

Good to keep in mind. Thanks again. 

By the way, how can the ballast be damaged by such "high frequency" operation? Is it because the initial strike is generally a lot more taxing to the circuits overall? 

Pardon the partial derail, but is there a good "care and feeding" thread for HIDs in particular? They seem a little touchy compared to LED-based lights, but are nonetheless very interesting to me. I looked at the "good threads" sticky but they were mostly comparisons between lights. I'm more interested in an overview of how to take care of a HID, warning signs to look out for, etc.


----------



## BVH (Mar 30, 2011)

My experience has been very good will many, many HID systems. Not really any care and feeding to worry about. The only thing I would refrain from doing is hot re-striking them. I'll usually wait a good minute or two if I have the time to wait. If not, well, I hot restrike them. I have a set in my 08 Chevy PU with auto-on headlights. If I don't manually turn the light switch to "off" before cranking the engine at night, I'll strike them when the key is turned, they'll go off when cranking and then they'll re-strike. This happens when I just plain forget. Re-striking requires higher Voltages than an initial cold strike. And like anything else, the more times it's used, the quicker it will reach the end of its' design life. I've had my 55 Watt kits installed since late 07 and have not had one failure.


----------

