Building a short arc searclight

Aha, 300 watt xenon, that make sense.
When it comes to these xenon power supplies from China, they seem to be in a very different class than the million different automotive “HID kits” online. I have no reason to believe the PSU itself don’t deliver what they are rated for (or very close to it) Not sure if it’s ok to post links here, so I sent you an PM with some links.
The metal halide lamps are entertainment/touring/stage/film lamps. Similar to automotive HID, just way more power.

Kudos for your ambitious/expensive project, but I think youre probably going to find it very difficult to focus the beam. Especially if you would like to have a variable/adjustable beam width (which makes these light far more useful). Also, the depth of your reflector in comparison to its diameter is far deeper than what I have ever seen in any proper HID/short arc searchlight, so I wonder if it would be capable of focusing such a light source.

If this doesnt work out, maybe you could sell your project for an astonishing profit at CPF and reinvest in a 1kW AN/VSS-3A searchlight. If you are diligent in your search, you can still find them with 0-3 hours run time on the envelope (they have an hour meter that records run time). Many come with the proprietary cables, control head and remote controller. Ive paid from $350-1000 for the several I have owned. Due to their superior optical systems and design, these completely trounce a 1.6kW Nightsun Ive compared mine to. They are also extremely rugged becasue they were designed to survive at the base of a tank barrel in battle.

Thanks for the info Polari. I'll check everything out when I get a chance. And it's okay to post links here. BLF is no where near as strict as the other forum which I'm banned from.

FlashPilot the reflector I have is very deep as you say. I wondered about how it would focus the beam myself but the previous owner managed to get 40million candlepower from his setup so I would think its capable of focusing a short arc light source. From the research I've done a deeper reflector is more effective at gathering all the photons and focusing them into a tighter beam than a shallower reflector. I'm not sure why many of the larger short arc lights use rather shallow reflectors but my reflector's depth to diameter ratio is similar to that of the maxabeam which has an extremely long throw for a rather dim light source.

And if I found a vss-3 in the price range you say I would definitely snag it. At the same time I would like to conquer building my own light and work out all the kinks as it something I can be proud of having built myself. For a flashaholic having a rediculously bright light is rewarding but having built one yourself adds another level to the reward that can't be had by simply buying a light.

Have you contacted Opti-Forms to find your reflector application and associated parts list? If they dont have that information on hand, perhaps they could provide the vendor they were manufactured for and other data. You might be able to copy or approximate the intended light source parts with stunning guaranteed results. The maxabeam reflector depth to width ratio appears to be a good deal less deep than yours. I had 10 of them for a project that I had abandoned before stepping up to the VS3 while saving a ton of cash. Maybe this mechanical drawing of a maxabeam can give you a few clues that might assist in your build.

I think the larger short arc searchlights use a large flat reflector because they utilize a comparatively larger gap between the anode and cathode, which would scatter the beam in a deeper reflector. Comparing your example of the 450 watt short arc with 3 mm gap (0.118”) with the 1000 watt VS3 gap of 0.132”, I wonder if your reflector would scatter the light with the bulb you mentioned. The VS3 uses a 14” relatively flat reflector. But then, maybe it wont matter; as long as you can culminate the hotspot. Any scattered light should result in a brighter spill beam, which can be far more useful in the wild than a sheer intense long range hot spot with no spill beam. I never run a VS3 in max spot while moving, and usually in full flood mode or somewhere in-between… max beam range far exceeds what naked human eyes can view in any detail, and the police wouldnt enjoy my attempts in spotlighting high altitude aircraft in transit. :smiley: Beyond that, its proven completely useless in the max setting.

  • If you havent researched the potentially lethal explosive hazards of xenon short arc tubes, you might want to take a good hard look before committing. The VS3 has an internal cradle mounted on elastomer pads to isolate and absorb vibration and shock, and they are still very dangerous. The housing case is thick hardened aluminum, so if (and often when) the envelope explodes, all the shrapnel will destroy the internal components and send them through the front of the lens. I treat mine like an unsafe loaded gun and store face down away from people when not in use. If you search, there are incidents of short arc tubes exploding while sitting unattended on a shelf… scary stuff without the correct equippement (bulb changer/protective housing) and safety protocols for handling and storage. PM me with your email address if you’d like the VS3 manuals and warnings.

Have fun! :bigsmile:

As an aside, Ive been running a pair of 100 watt HID’s in my pickup truck driving lights (Hella Ralley 4000 with 9” reflectors) for nearly 4 years without incident. They have many hours of sustained use in a high vibration environment, which would kill most Chinese HID systems. This particular design is highly touted on 4x4 forums and has given others good results as well. Your thread reminded me of another pair of Hella 4000’s I picked up and forgot about, so I just ordered another 100W HID kit to convert them as well. They provide around 9000 lumens each, have ceramic mounting bases and very high quality ballasts that dont flicker and always ignite. Ive tested mine down to –4 F. Im told that the ceramic base 70 watt HID bulb can be used with the 100 watt ballast for higher surface brightness in a smaller envelope. This should translate to a more concentrated beam in your deep reflector for longer range but with less total lumens. Perhaps the best part is that the kit is only $70 for a pair of them (with free shipping). You could use your spare HID and convert a Coleman spotlight like the one I did a while back. Then you could have a killer thrower with your project and a cheap medium thrower for your car that would still slaughter anything LED. I went with 4300k (appears to be about 1A Cree tint) for max lumens and H1 bases to match the Hella 4000’s and the Coleman spotlight. 100 watt HID sales link (only 2 days left) Id stay away from the other Chinese 100 watt versions because they have been notorious to failure and being underpowered. The link does a good job of explaining the differences in the electronics. You might also ask about higher wattage ballasts and 70 watt blubs… if you’re interested.

I think ma-sha1 had this reflector custom made so I'm not sure how to explain to Opti-forms which reflector it is so that they can give me its specs. I'll see if I can get in contact with ma-sha and see if he still has them available somewhere. He hasn't been on this forum is 6 week though...

That cut away of the maxabeam is a very useful pic. THanks for that! Maybe I can steal some of Peak Beams trade secrets. I have figured out in my mind how I intend to mount the lamp. Should be easy. It's figuring out how to hold the reflector and the front lens to the pot securely without damaging either one, while also keeping it pretty that's got me stomped at the moment. Can't seem to find the type material I need in the stores no where.

And yes I'm aware of the danger of short arc lamps. I had highly considered using a mercury short arc lamp because of its higher efficiency than Xenon but the massive amounts of UV rays it produces is what led me to ditch that idea. The center glass in the window I'm using, I'm sure, blocks UV rays as it was removed from a UHP lamp. But the outer polycarbonate is what I'm not sure about. It may allow free passage of all the UV rays, and if so, it would be quite a bad idea to use a Mercury lamp. Also apart from not knowing exactly which bulb I want to go with, one of the reason why I haven't ordered the bulb just yet is that I don't have all the required safety gear to handle a one of these lamps, let alone bench test it.

I would love to run some auxillary lights on my car but I don't really have a great way of mounting them. My HID projector retrofit also puts out a ton of light as it is so I'm pretty much satisfied with my headlights ATM. I do intend to mod a flashlight but this project is gonna suck up all my money for now LOL. My FF4 and TN32 will have to do for the time being.

Is there a part number on the reflector lip base or side? It might be very small, ink jetted, laser etched or engraved.

I was thinking that the 100 W HID I linked might be a good place to start for a minimal investment with your light source to see how well your reflector worked. At 9000 lumens, its probably far more efficient than a short arc and could be ran off a 12 volt cell (car battery or li-ion remote pack). Also a lot safer than arc laps. More isnt always better when you’re trying to concentrate the beam.

Halogen lamp housings are all supposed to be sold with a quartz lens to arrest UV. Im not sure if a quartz lens would provide a sufficient filter for mercury arc, but it might be worth investigating. Youd have to find the amount of UV produced at peak luminous flux and calculate the amount of concentration culminated through the reflector… more fun (or headaches) depending on your point of view.

A lot of people use JB weld epoxy in their builds because its nearly as tough as steel and can be sanded. They also have a putty version that can be rolled like clay before forming.

I do have to wonder how your reflector might work with a Cree XHP-35 HP. Sure, it wont walk the walk like HID, but it might be pretty darn efficient for a mega LED thrower. In fact, Im more interested in that potential than HID. :stuck_out_tongue:

When you start to add the cost of parts and the intricacies of a proven, evolved, well engineered short arc searchlight - good second hand units are a real bargain if you have a use for such a thing. I for one was never impressed with the maxabeam because it seemed under-powered and had an awful beam pattern when zoomed out. They always reminded me of a maglite beam, which was the main reason I gave up the 10x maxabeam project. The VSS3 adds a variable reflector warping system, which automatically maintains an optimal reflector parabola as the bulb moves in and out of the reflector on a motorized rack and pinion system… which is why the beam pattern is always nearly perfect at any zoom setting. No maglite/maxabeam/nightsun beam pattern ugliness in the VSS3! :bigsmile:

Just cruising the adds, I spotted this old 60” monstrosity. Id guess it to be a GE or Sperry, but hard to tell the condition. Pics look good and it appears complete. It might be a real bargain for the asking price and probably negotiable. If it were mine, Id consider a 5-20 kW xenon arc donor conversion from a movie projector or lab equippement.

Don’t worry about Mercury lamps and UV with a Polycarbonate lens. It will absorb all the dangerous short and medium wave UV, no matter what brand it is. A slight amount of UVA in the upper spectrum will pass, but you get a lot more of that from the sun anyway. You can google polycarbonate uv transmission and look at graphs. You will see that Polycarbonate block more UV than a ordinary glass or borosilicate lens that usually is used on short arc lights.
When that is said, you may not have UV resistant polycarbonate. It will block the same rays, but the plastic will yellow and deteriorate over time. No huge deal though, as you can get a new sheet for like $15-20. And for the record, Xenon also produce a lot of UV, so you won’t avoid that potential issue completely.

As for installing the reflector, feel free to do what I did. Cut a hole in a thick aluminum sheet, chamfer it so it fits the reflector profile, and glue it on with high temp RTV silicone. Then you atleast have a solid piece of metal you can attach to the housing. Silicone was recommended to me by Phoenix Electroformed. It has a slight give so you don’t risk deformation due to thermal expansion. I’m actually about to install a new reflector as we speak and I can send you some pics when I’m done.

There are very few arc lamp builds in BLF, subscribed!

I don't see a part number anywhere on this reflector. The only symbols on it are a cresent moon shape, and the symbols AQ which tells what type of coating it has. Haven't had a chance to send ma-sha and email yet but Ill get to it soon.

Being that I also modify headlights I have quite a few automotive style 35watt HID bulbs laying around. I decided to throw one in and see what kind of results I got from it as you'll see below.

I would love to see how this reflector would perform with one of the high powered LED's myself. Unfortunately I don't have any laying around to test it with though. Hmm you got me thinking maybe I ought to go buy a cheap XML flashlight and strip it down and see what kind of results I get before installing the arc bulb...

Great info on the UV rays Polari. Thanks a lot! I didn't realize a polycarbonate lens would block most of the dangerous UV rays. I guess polycarbonate lens are perfect for my application then. Not sure how resistant it is to UV either but being that the light probably wont to used very often, hopefully I wont have any issues with it yellowing. I also see there is a lot more research on UV rays , and polycarbonate lens I probably need to be doing LOL! All this is uncharted territory for me. Got a lot more research and learning to do before even placing an order for the bulb or ballast. Don't need any accidents.

The way you described how you mounted your reflector to the pot is exactly how I was intending to mount mine. The previous owner had already used some type of high temp muffler glue to secure a small piece of aluminum to the reflector. I guess I can just cut a larger piece of aluminum to fit as a lip on this smaller piece and then use this larger piece to mount the reflector to the pot. Probably have most of the supplies already here to mount it with.

The depth of this reflector has had me a little worried since the day I bought it. Probably about the deepest reflector I've ever seen, and that had me seriously questioning how effective it would be at focusing the beam into a spot as tight as I was hoping to get. Flashpilot raised the issue again and so it sparked my curiosity even more, so even though I was super tired from work this evening I had to go test out this reflector with one of my automotive HID bulbs.

With me I took a Morimoto(aftermarket) 35watt H1 HID bulb powered by a Toyota Denso 35watt ballast, FF4 65watt, my TN32, Extech LT300 light meter, and a laser distance measurer. According to my laser distance measurer I was 28.3 meters (92.8 feet) away from the wall I used for my beam shots. I held the HID light inside the reflector by hand since i had no way of mounting it yet and tried my best to keep the beam focused on the light meter. I probably never got it perfectly focused so the number I got from my lux meter are probably very low. On top of this my lux meter has consistently read lower than many of the other guys on this forum who have the same lights as me, so the actual lux of all the lights tested are probably quite a bit higher than what I tested them at. Any way here are the numbers I got.

--------------------------------------------

Distance the lux is measured at is 28.3 meters.

Formula used to calculate lux at 1 meter is ...... (distance^2)xlux=lux at 1 meter.

Lux for the 3 lights is listed below:

TN32 on turbo =193 lux @28.3meters = 154,571.77 lux/1meter

FF4S on 65watts =353lux @28.3meters = 282,714.17 lux/1meter

35watt automotive HID =2998lux @28.3meters = 2,401,068.22 lux/1meter

---------------------------------------------

Beam Shots. Camera was set to manual and all the setting remained the same.

TN32

FF4S

35watt HID in reflector

The wire on the side of the bulb is causing a major shadow there but overall the beam profile is very nice. Seems like it is very much capable of tightly focusing the light produced by a short arc bulb. And the center of the beam is so intense it actually appear to be rivaling my Maxabeam LOL! I'm highly satisfied with the performance of this reflector! Never seen anyone get 2.4 million lux from a 35watt automotive HID bulb LOL!

That’s a good start, with a stock pot and a shiny funnel!

Okay, so the ultimate arc recipe goes:

  • 8 quarts sunlight
  • 2 dozen lithium batteries (chopped)
  • 1 cup LED emitters (dedomed)
  • 18 linear inches 3/4” (OD) copper pipe (grated)
  • Bring sunlight to a rolling boil
  • Add lithium and LED’s
  • Boil until mixture thickens
  • Line funnel with cheesecloth and strain. Discard solids
  • Season with copper to taste

Seriously though, can’t wait to see what you make

It looks like you’ve got a winner! That must be quite a relief. Just imagine what it would do with the 100W HID (3500 lumens vs 9000). If the wire shadow becomes an issue in your final build, you can index it to the bottom and it will go mostly unnoticeable as you shine it on targets. Check My 100W HID beam shots for reference.

Did you receive my emailed with the VSS3 manuals?

Now that’s a hotspot! Like, literally a hot spot :wink:

[quote=FlashPilot] It looks like you've got a winner! That must be quite a relief. Just imagine what it would do with the 100W HID (3500 lumens vs 9000). If the wire shadow becomes an issue in your final build, you can index it to the bottom and it will go mostly unnoticeable as you shine it on targets. Check "My 100W HID":https://budgetlightforum.com/t/-/4293 beam shots for reference. Did you receive my emailed with the VSS3 manuals? [/quote] I did get your email. Thanks so much for sending them. I sent you a pm about it.


After I looked over the link Polari sent me I'm thinking about going with their 500watt ballast. Osrams 500watt Xenon short arc bulbs are about 13000 lumens so they would beat a 100 watt Metal Halide in brightness and intensity!

Has anybody tested the results of having the wire on the side of bulb follow the bulb envelope(like automotive HID) vs running along the glass window and down the side of reflector like the maxabeam? I wonder which way would create a bigger shadow.

I never got your PM reply. Anyways, Im glad you received the manuals. Now the fun begins!

@Polari - can you share your link with us? Im starting to get the itch for another large short arc. :bigsmile:

Sure, it’s http://www.proteus-electric.com/ But I can’t guarantee you anything. Have neither tried any of the products or bought from them. But it seems legit and I did get a quote from them. You will also find more of the same style PSU’s on Aliexpress.

I sent them an email about their 500 watt ballast. If anyone is interested I'll post their reply. If the price is not too high I might take a chance and order from them. Im willing to be a guinea pig

Thanks guys. It all looks doable. This isnt CPF, so there’s nothing wrong with keeping everyone in the loop with prices and links.