# How bright is 5 million candle power?



## Cavelightchris (Feb 25, 2008)

I just got back from sears and they had two inexpensive Dorcey spotlights there. One said it was 1 million candlepower, and it looked like the bulb was tinted blue for some reason? The one that I was most interested in was 5 million candlepower. The replacement bulb for it was $5, and I think it said it was a 6 volt bulb. I want to buy that bulb and make my own headlamp out of it, does this sound like a good idea? I don't care about runtime, I was thinking about making my own battery pack that used 4 C's to power it anyhow, I want to use the thing for filming in caves, and so all I need is like 20 minutes of run time anyhow.

My question is this:

Does anyone have a beamshot of a 5 million candlepower light so I can see about what it should look like?

Also does anyone have any advice for me about making my headlamp using the replacement bulb? I am guessing my headlamp is going to get real hot, and so I am sure a glass lens is in order, but I have no idea what I am going to use for a reflector. I want something that can spot and that would have tons of useable sidespill(for filming reasons). It also can't get so hot that it is going to melt, any idea's?


Bare minimum I was wondering if someone could at least tell me this; is 5 million candlepower a whole lot? About how many lumens would that equate to, anybody know?


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## KeyGrip (Feb 25, 2008)

There's no simple way to equate lumens to candlepower or candlepower to lumens. Long story short, they measure two different things. Also, the majority of the candlepower claims on lights like the ones you found are over inflated advertising numbers. About making your own headlamp, ask around in the "Home made and modified" section here. There are plenty of members who make thier own lights and can give you advice on reflector material and things like that.


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## Fusion_m8 (Feb 26, 2008)

Depends on which end of the light you're standing...


Seriously now, it would be difficult to show you accurately in pictures just how bright 5million CP is, but as a comparison, there's a 15million CP light outdoor beamshot here. For 5million CP, just take it as half as bright as the 15million CP light...


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## mdocod (Feb 27, 2008)

Go ahead and forget about the big candle power numbers for a minute, as mentioned already, it's become much like watts on audio gear, very much inflated and pointless. 

Lets focus on what the bulb actually is:

Generally speaking, these are 6V 55W halogen bulbs mounted in H3 or similar automotive housings. They run around 9 amps and require a pretty low resistance power source to run effectively, ideally speaking, they should probably be overdriven to around 7V to get more efficiency. 

If you are looking for a way to get some serious power into a headlamp, I HIGHY suggest tossing the idea of using one of these bulbs aside. Running it on 4 C size cells won't work very well, You could run it on 5-6 NIMH C size cells for about 20 minutes I suppose, but it's still not very practical.... It's probably overkill to be honest... I can understand the lure of bringing something really overly impressive into a cave.. (I have done it).... But may I suggest a higher voltage configuration, lower current, slightly lower wattage, more bulb overdrive for better efficiency. 

Build a housing from various plumbing parts to hold a 12V 20W MR-8 or MR-11 or MR-16 style lamp (these are bulb/reflector assemblies found in track lighting and various other places).. This will save you the trouble of figuring out a reflector and everything as the reflector is built in. Pick out a "4000 hour+" bulb to work with.... You are going to overdrive the crap out of it to the tune of about 40W so it will become something more like a 10-20 hour bulb with a ton of output. You can use a common bi-pin base to mount it in, or just solder some wires to the lamp and cut em when it's time to replace... whatever you want...

Buy 2 "9.6V" NIMH packs, sub-C packs would work pretty well and give some reasonable runtime. You could actually get over an hour with some of the higher capacity packs available. Go with an RC style pack in the 3AH range and you'll be fine. Wire the 2 packs in series for a "19.2V" pack and get a good slid rocker or toggle switch to handle the switching and rig it up.


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