DIY Fresnel, using rechargeable spotlight
 

Hey all,

I've been using my clamp hardware lights for a while now, and was gonna spring for some lowel gear, then I keep reading about a lot of people doing diy work with worklights and getting great results. The only disadvantage I find to worklights is that they flood light sooo much. My question is has anyone designed a focusable type light DIY>? I've been looking at those rechargeable spotlights that usually say 1 million, or 2 million candlepower. I'm wondering if I can use a light like that, always leave it plugged into the wall charging...or somehow add a chord to it, and get some kind of lens or moving elements on there to focus the light like a fresnel. That would be awesome if something like that is possible! Does anyone use these spotlights?

Anybody let me know if you have ideas.

Luke

Finding the appropriate fresnel lens could be tough. The spot your talking about is more of a PAR with the spot lens. A PAR has a bit of a different reflector and bulb arrangement than the classic fresnel layout. In a par there is a super parabolic reflector with the bulb in the center. In a fresnel there is a parabolic reflector and a bulb in front of it. The entire assembly can be brought toward the lens or away from it.

The closest thing I've done to what you're talking about is I took an old Kleigl Brothers Fresnel (1K) from Ebay, took out the wiring and old socket and added a new socket, an electronic 150w metal halide ballast, a 150w ceramic metal halide (CMH) and now it's a CMH "HMI" type fresnel. 5290K CRI 80 for that bulb but I can get a 90 if I like. It easily puts out as much light as a 500w fresnel.

I put an multi part article on it for my blog. The first installment covers some of the theory behind finding a generic equivalent to "HMI".

http://www.coollights.biz/wordpress/archives/31#more-31

Converting Work lights enclosure to take HMI
 

Hi Mr Cool Lights. Love your blog and your site. Any suggestions about modding a work light enclosure to take a HMI light bulb.. Cheers!

Hi Anmol,

In fact, it probably wouldn't be so hard, but I wouldn't recommend it because it would be an open face solution most likely and you probably know how I feel about open face metal halide from comments in my blog. UV, potential for exploding bulbs, intense heat emanating from the bulb, etc. I think these are all reasons why there aren't any small and portable metal halide work light's commonly available--because there's certainly no reason it's not technically possible. And there are small metal halide floodlight units available from certain industrial type lighting supplies to prove it can be done.

To be technically correct, if you were going to attempt this, you should use a beefier R7XS socket than the R7S halogen that's already there. That's an HID version which can take the higher starting voltage pulse. You would use this with the 150w RX7S metal halide double ended bulbs, like the one I used in my fresnel project in the article in my blog. The only problem you may run into is the distance between the sockets is a bit more than the halogen R7S bulbs that normally go in there. Then, choose an appropriate 150w electronic ballast and you have your MH work light. The fixture itself will get incredibly hot but the light emanating from it will be relatively cool. Hence why I chose metal halide to be our "cool" hard light. You should get somewhere between 10,000 and 13,000 lumens from a bulb like this.

By the way, for everyone interested (and there seem to be a lot based on my daily emails), I just posted Part III of my metal halide article series where I'm talking about what I've really been up to behind the scenes with the "Hard Light Series" we'll be offering soon and our progress there. Quite a bit more detail now to fill in some blanks and answers to many of your questions.

http://www.coollights.biz/wordpress/archives/36

Part IV should be along soon too to talk in more detail about bulb choices in the Hard Light series using Osram metal halide series (like HMI for instance) as the benchmark and then comparing other usable ones for replacement purposes in our Hard Lights.