turning hid on above water

[alo100]

Michael,

Does the light has over heat protect? In other words, auto shut off. Do you have any test result on flash lights with different power (W) for the longest time it stays on before the bulbs broke, on land and under water etc?

Does the life of the bulb become shorter when it is used in a dive light (enclosed environment, no ventilation) in general, or the shut off does do the protection properly?

Maybe one more, how much power is converted to light and how much is coverted to heat depends on the efficiency of the bulb, do you have any comment about which kind of HID light bulb is more efficient (more light, less heat)? e.g. Mg Halides or Mercury vapour etc.


Thanks!!!

 

[micbu]

Hi,

I talk about BS now:
Over heat protection? This is not necessary. You would be surprised how little heat is produced! The only thing you have to care about is the heat that is radiated to the bulbs side. Therefore plastic reflectors are not recommended, use aluminium ones.
Surprisingly a good ventilation of the bulb with current air lowers the bulbs lifetime!
A closed environment is absolutely no problem. The shut off of the ballst does its work properly, don't worry about that.
The ballasts of the 10W systems consumes appx. 12W. That means that appx. 2W are lost if really 10W go to the bulb. That is something that I have not measured yet.

I did never testings under water, only in our lab above water. I do not think that there will be a difference. You have a closed system that does really not produce too much heat, so it should not matter.
I will prepare an EXCEL sheet with different configurations and measured average test results. I will send it to you after that I have finished it. Will you please tell me your e-mail address in a private mail?

I have never done a direct comparison between Mg Halides and Mercury vapour bulbs, sorry.


Greetings, Michael

-----------------
www.hid-tec.de

 

[micbu]

Hi,

sorry, I forgott to write that the tests with the 10W Bulbs were done with the old versions. The newer ones do have a longer lifetime, but the conclusion will still be the same. DO NOT SWITCH TWICE WITHIN 4 MINUTES


Greetings, Michael

 

[Meng_Tze]

Hi,

You would be surprised how little heat is produced! The only thing you have to care about is the heat that is radiated to the bulbs side. Therefore plastic reflectors are not recommended, use aluminium ones.

-----------------
www.hid-tec.de

Not to nit pick, but if the advise is that AL reflectors are used rather than plastic ones.... surely enough heat is produced to warrant this warning (i.e enough heat is produced to advise not to use plastics)? To me the above statement is contradiction in itself. If on top of that you have the buld housed in a test tube with air in between (a pretty good isolator in many applications)......radiation heat is still heat

 

[micbu]

Hi,

partially you are right, BUT:

The ballast does not produce much heat. That a bulb is producing hest, that is no question, what do you you expect? A cold fire? If we are talking about heat production then we talk about the ballast. But even the bulb radiates the heat in just one direction. If you use a plastic reflector then you will get a hole at just one, depending on the bulb, maybe two holes in the plastic. The total system will relatively cool.


Greetings Michael

 

[Meng_Tze]

Hi,

partially you are right, BUT:

The ballast does not produce much heat. That a bulb is producing hest, that is no question, what do you you expect? A cold fire? If we are talking about heat production then we talk about the ballast. But even the bulb radiates the heat in just one direction. If you use a plastic reflector then you will get a hole at just one, depending on the bulb, maybe two holes in the plastic. The total system will relatively cool.


Greetings Michael

???? The ballast never came in question. The whole system is not applicable in this instance. The ballast does not even come close to its upper level of performance in terms of heat in the electronics. The spike it needs to deliver to strike is relatively short.

The issue is that when you have a bulb enclosed in static air (bulb in a tube) the bulb can not dissipate as much heat to the surrounding environment as it would in open air. This leads to increased heat inside the bulb. If you have a thick walled bulb (newer BS) then it is less of an issue, but with older style BS and WA bulbs, the heat build up increases the pressure inside the bulb as well, potentially to the point of where this can not be maintaining structural integrity.... pop!

If you on top of that have the bulb 'preheated' by a previous ingition, the build up and especially the initial ionization of the gas, increases the pressure far quicker than when a buld was cool to start of with. This is why it is advised to let a bulb cool off before restriking.

But previous responses Michael makes me wonder....... could a plastic reflector be used in a 'open air' config? No test tube, just a bulb with a refelctor.

If no, then the bulb vreates even more heat than I thought. If yes, then the insulating capacity of the enclosed air is much higher than I thought.....

 

[micbu]

" ... could a plastic reflector be used in a 'open air' config? No test tube, just a bulb with a refelctor."

Well, that is something I have not tried yet. I could imagine that this is depending on the used reflector size. For sure a MR11 reflector is closer to the bulb as a MR16 reflector, so a MR11 is probably easier to destroy as a MR16 one.


"???? The ballast never came in question."

of course, alo100 was asking for an over heat protection. You can have an over heat protection for the electrical part of a system, but not for the bulb. Neither BS nor WA do have sensors outside the ballast to monitor the heat of the bulb, so he must have been talking about the ballast.


Greetings, Michael

 

[Meng_Tze]

"
"???? The ballast never came in question."

of course, alo100 was asking for an over heat protection. You can have an over heat protection for the electrical part of a system, but not for the bulb. Neither BS nor WA do have sensors outside the ballast to monitor the heat of the bulb, so he must have been talking about the ballast.


Greetings, Michael

I guess you are right in your deduction. Not sure alo100 was talking about the ballast per se, but your logical deduction must conclude this indeed.

 

[alo100]

I guess you are right in your deduction. Not sure alo100 was talking about the ballast per se, but your logical deduction must conclude this indeed.

Only the bulb needs the heat protect, I think, since the ballast only consume 2 W. I am not familiar with different designs, one of the user (10W HID) told me that his/her light has thermo feedback: reflector -> connecting wire -> thermo resistor -> feedback ckt at the ballast to shut the light off. So, remember it is only a 10 W HID. Then when Michael told me:

Surprisingly a good ventilation of the bulb with current air lowers the bulbs lifetime!
A closed environment is absolutely no problem. The shut off of the ballst does its work properly, don't worry about that.

I was kind of surprised, because I thought if a 10W light is using it, then Michael's 35W, 55W lights should have something similar.... no further comment, right?

Some people are also suspecting that when the CONNECTION between the reflector and the thermal resistor is not having a good connection (meaning the quality control of the light is bad) the light could fail to shut off, anyway this is a guess.....
Notice: the temperature at the reflector may not be the same temp as the bulb.
Anyhow, that particular light is famous for bad QA at least for a period of time.

and when Michael is saying that the ballast is working fine for the set up, I will take it, as long as he realized that the bulbs they are using actually does reach the expected lifetime given by the bulb manufacturer.
It does, right Michael?
Can you post some of the data at this forum, I am sure other potential customers are around ;-) i.e. when the light is turn on continuously for hours, any stress test, burn-in test results? just want to get an idea....

The "pop" of the bulbs could be due to switching/heat -- like Meng said.
Or the difference in temp --> like Michael said "current air lowered the lifetime"
heat inside the bulb builds up vs. cold media outside, on both sides of the bulb surface, maybe?

Any thoughts, comment, idea?

 

[micbu]

Hello,

I have now attached an EXCEL sheet with measurements. The values are average values measured by me in a laboratory.


Greetings, Michael