What short arc for maxabeam-like searchlight?

Enderman

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Hi, I'm planning to build a flashlight similar to a maxabeam, but I'm not as familiar with short arc bulbs as other people here are.
If all I'm trying to get is throw, is there any better option than the same bulb that the maxabeam uses?
Shorter arc with higher intensity maybe?

If there is no better option then it's pretty easy to get a maxabeam bulb from ebay or someplace, such as this one http://www.ebay.com/itm/Maxa-Beam-M...ght-Peak-NEW-in-Box-MBS-410-430-/171630234252
Thanks for any help :)
 

PolarLi

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I believe the 100W Osram HBO (mercury) lamp Ra used in his maxablaster has a shorter arc gap and higher intensity than the Maxabeam Xenon lamp. Not sure if you find a low voltage ballast for that one. An alternative where you do get a low voltage ballast is Ushio SMR or SMH lamps. These have a 1.2 mm arc gap and can be driven up to 100 watt using this: http://www.rotec-gmbh.com/images/lightning/downloads/Datenblaetter/Rotec-datasheet-bcs-75.pdf
The lumen output should be around 5000-6000, but I can't say for sure if this lamp actually is enough to beat the maxabeam in throw, used in the same size reflector.
You also get the low wattage Solarc lamps from Ushio 10-50 watt, these also have low voltage ballasts you can buy directly from Ushio. Prepare to pay premium for all of the above...

Now, if you are willing to use an inverter to get mains voltage, you can builds all kinds of crazy lights using UHP video projector lamps. I was able to get 55 Mcd from a 7.9 inch reflector using a 350 Watt UHP lamp so they do throw good... But with these wattages, you need fan cooling, a hefty battery and 380 volt DC, so either an inverter to PSU to ballast, or a modified inverter where you can tap 380 volt DC. Either way, it wont be an EDC light... You also need to hotwire the ballast, and cut the lamp out of the reflector. (reflector cutting also goes for the Ushio lamps)The plus side is that these UHP systems are cheap.
 
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Enderman

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Thanks for all the info!
I have heard a lot of talk of the osram HBO 100w/2, and it's apparently ~0.5mm arc gap and 130 000 cd/mm^2, is there somewhere I can find the spec for the maxabeam bulb?

Also what is the arc gap for UHP lamps? is it a lot shorter?
55mcd sounds great and this isn't supposed to be an EDC light, an external battery and fan cooling will be used regardless of what lamp I use, although all the inverters, ballast, etc... sound extremely inefficient and heavy...
 

PolarLi

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I'm not sure what the maxabeam lamp specs are. Hopefully someone else can fill you in on this. But we know it's a xenon lamp. And Xenon have a very intense hotspot at the cathode tip that is great for throw - if you pair it with a high precision reflector.
Another big plus is instant on. No warm up.

UHP lamps on the other hand are AC driven, just like all automotive lamps and other metal halide lamps, and have two hotspots, one at each electrode tip. This is generally not good for throw. But because of the short arc in UHP lamps, only 0.8-1.3 mm, and a lot of power, these two hotspots more or less merge into one. I actually took a picture of the arc of that 350 watt lamp I mentioned.
The arc gap you see on that lamp is 1 - 1.2 mm, and it's producing around 19000 lumens:
clXmhZG.jpg


Btw, what is your "throw goal"? And how big reflector can you use?
 

Enderman

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Ah I see, I guess UHP would be great for a lot of lumens too.
I actually might still have the ballast for a 200W UHP lamp I have lying around, I will try getting the ballast to turn on later in december or january.

There is no throw goal, just something with farther throw and more lumens than my 1Mcd aspheric.
The reflector will probably be a 6" phoenix, although I found a used 9" optiforms reflector for like $50 so I might use that too. Not sure yet.
The maxabeam reflector is about 5" so I figured a bit larger would work just as well.
 

PolarLi

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1-2 Mcd is within reach for automotive HID's, so that aint to hard to get. But definitely take a look at that 200 watt UHP system you may or may not have. I tested a so called 5R lamp and ballast in that 7.9 reflector, and with a 1 mm arc gap (approx) and 190 watt going to the lamp I got 37 Mcd. So based on that with a 6" AQ reflector, perhaps 20 Mcd?

On aliexpress they sell packages with this 5R lamps, 200 watt 1 mm arc, complete with ballast for around $45, and if you search for "moving head power 5r" you find the 380vdc power supply for around $60.
 

Enderman

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$45 sounds great for a combo like that.
The 380vdc power supply is driven by 120/240v AC correct? So I would need a 24vdc to 120/240v ac converter?
 

PolarLi

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Correct and correct!
But there may be another, more compact and even cheaper option for the power delivery. It only require a simple circuit and some soldering. I do have the "device" here. But I never actually tried it out on the actual ballast and lamp. But I will give it a try today or tomorrow. I'll let you know how it turns out.
 

Enderman

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I did more research, it seems the maxabeam uses a UXL-75PB Ushio lamp, but I sent an email to PeakBeam just to confirm that the gen3 is still using this lamp, because it might have been changed from gen 1/2.
The UXL-75PB has a 0.8mm arc gap, 1000 lumens, and 90cd horizontal (not sure about cd/mm^2)
The HBO103W/2 has a .25mm arc gap, 3000lm, and 300cd horizontal (170000cd/mm^2)

So yeah, the HBO seems like a MUCH more powerful option than the stock maxabeam bulb :)
I also sent an email to osram to confirm that this is the highest cd/mm^2 bulb they sell, just in case I missed something in the spec sheets.

Now I'm going to look for some cd/mm^2 specs for UHP lamps to compare to the HBO103W/2.
 

PolarLi

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So I did get the UHP lamp to run on a car battery, kind of... I used a 12 volt DC-AC inverter, 500W. These put out 380 VAC and cost about $10 on ebay. On the output I have a rectifier and a capacitor. The entire thing weigh maybe 200 gram so it's a compact solution. However there is problems. There is no voltage regulation, so input must be spot on for it to actual deliver 380 volt. Small changes in input voltage send it from 300 volt-ish, to over 400 volt. So if you use this on a small battery pack, the voltage will be all over the place depending on how much juice the batteries have left. The other issues was to little power to the lamp. Was missing almost 30 watt, so the ballast is not liking it. So if you go the UHP way, I recomend to first get it to work with a normal AC-DC power supply, and do some tests with that, before you try other ways of supplying power.
 

Enderman

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Ok cool, thanks. PeakBeam replied and yes the maxabeam uses a UXL-75PB lamp.
I'm really tempted to go with a HBO103W/2 because it seems like there is no "proper" solution to power UHP lamps from a battery...

I was searching for ballasts for the HBO103W/2 and only found two:
https://www.aelight.com/content/ballast-mercuryxenon-short-arc-xbo-35-75w-hbo-75-103w
This is the one first used in that maxablaster or whatever it was called by Ra, but half way in the thread he said that it died on him.
It also doesn't seem great because it needs an igniter and has a bunch of plugs on the board, and little documentation.
Then he switched to the second one I found which is below:

This one actually runs on higher DC or AC voltage so I would still need a step up to run off of 24v lipo, but documentation is much better, has built in cooling, built in igniter, and seems much better quality:
http://www.celinius.com/index.php?p=portfolio-item&s_q=HBX76
It costs $500 but I want something that will work, not burn out like in the maxablaster, so maybe the loss of efficiency in the inverter will be worth it
Same brand as the first ballast you linked me, but unfortunately that one only works for ULR, SMH, SMR lamps and not HBO :C

Thoughts? Any other ballasts around that work for the HBO103W/2?
I'm guessing a random 100W ballast from ebay is not going to do the job because the lamp voltage, current, and ignition voltage need to match up.
 
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PolarLi

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As you said, the ballast you found on the celinus site are the same brand Rotec sell, but they also have all the other models if you go to their main site.
And those products are definitely good quality and plug and play. Ushio also sells the same ballast called "Smartarc HBX-76" And I think that was the one Ra used.

But I don't know of any other ballast for that lamp that could be considered compact. However, you can find used stationary units on Ebay if you search for HBO power supply, but these are big, heavy beasts.
As for random ballasts, I wouldn't personally go down that route. I have blown up one lamp by not using the proper ballast, and I don't want to repeat that.
 

Enderman

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Oh yeah, rather not cheap out and have a mercury explosion xD
Thanks for the search terms, I see all the HBO power supplies now.
12/24v to 120 or 220v inverters are everywhere, so finding a good one for less than a hundred bucks is easy.
I will probably go with the HBX because I want this light to be portable, although it will take some time to save up for that.
At least I've got the parts list down now :) Thanks for all the help!
 

PolarLi

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Yeah, forgot about Scheiderwerk. I actually have a HMI ballast from them. And their products seems to be top notch. But they don't to sell to private customers. The last time I was in contact with them, I asked them a simple yes - no question about the brand new ballast I had bought on ebay. But they basically said they had the answer, but refused to give it to me beacuse I wasn't an authorized dealer :ohgeez:
 

Ra54

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Hi guyzz,
I'm very pleased to see that my Maxablaster, which I created in 2006, still is going strong in your minds today.

I'm not very pleased that, probably because I was away for a long time, I could not login to my good old "Ra" account..
And so needed to re-register, now with more than 3 characters in my username.. So I'm a newbee now..
A newbee with a history..
It is nice to see that almost everyone who tries to make a powerful short arc torchlight, sees Maxablaster as the big example.
I'm going to do some reading now.

BTW: Maxablaster still is very alive, in my bedroom closet.. Needing new batteries, but that will happen soon.
 

PolarLi

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Welcome back!
Great to see you around here :thumbsup:

And there is a reason why people still bring up your light, beside the fact you made the first homemade SA light, and set the standard with that. Thing is, I can't recall there has been built many self contained, portable SA lights here or anywhere for that matter. I know one person made a similar light a few years after you, but other than that, nothing? Most SA projects seems to have been less portable lights or lights with not so good reflectors.
 
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Ra54

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Hi PolarLi,
It indeed involved a lot of thinking to complete Maxablaster the way I wanted.
You are totally right about the importance of the reflector, i needed to work on the front of the reflector, to prevent even the smallest deformation when the reflector was mounted touching the front window.
Indeed its a painstaking job to make the reflector send all the light of a 0.03 square mm arc into that one point at infinity..
 
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