Do you have experience overdriving halogen bulbs.

[Flatliner]

Any of you have experience overdriving halogen bulbs?

What I want is:

1. More light
2. More correct color

What I don't want is:

1. WAY too much heat
2. Exploding light bulbs

What I don't care about is:

1. Shortened bulb life (within reason)

Any advise backed up by personal experience is greatly appreciated.

Flatliner
aka Robert

[Dale]

Some estimates of overvolting the bulbs is that 10% overvoltage will result in 50% bulb life. The hotter the bulbs are, the lower the resistance. You might expect the power the bulb draws to go as the square of voltage (P = (E*E)/R), but as the heat rises, the resistance drops. So, more voltage, hotter bulb, even more power drawn.

I'm not sure why you want to do this. Bulbs are remarkable "correct" as to color, a bit of manipulation with Photoshop (or, the GIMP) will correct for any color balance problem and more light can be much more easily had by selecting a higher wattage bulg.

FWIW, I built a 50Watt 6 Volt dive light some time ago. The thing was so bright that on entering a cave with it, all the other divers started hitting their lights wondering why they weren't putting out any light. I'm also in the process of designing another 25W to 50W 12 volt dive light.

Good luck, but I'd not overvolt the things.

[Theepdinker]

Try here. http://www.candlepowerforums.com/vb/
I'll warn you now.
You could get stuck there for days.

Theep

ps What you want to do is referred to as a "Hotwire"
Also dive lights & other high output lights are usually driven
closer to the filiment melting point than say a Maglight.

[ianr33]

Originally Posted by Dale

, but as the heat rises, the resistance drops.

That is incorrect. As the temperature of a metal increases so does its resistance

http://en.wikipedia.org/wiki/Resistivity

[in_cavediver]

There is a yahoo group on DIY canister lights and in their archives, there are a couple of Dive light controllers designed to safely overdrive bulbs with smart switching. Basically, the idea is to underdrive the bulbs initially to get the halogen cycle going and then up the voltage to overdrive them for use.

Personally, If you don't like the spectrum, I look for different bulbs or different technology. I do know that you can order specialty bulbs of different colors (4.5k, 5k, 6k etc) and wattages. I'd try one of those first in a higher wattage.

[creggur]

Originally Posted by Dale

;but as the heat rises, the resistance drops. So, more voltage, hotter bulb, even more power drawn.

.

I think you are thinking about semi-conductors....At least that's what I learned in Navy electronics school.....Of course that was 15 years ago so I could be wrong...

[Flatliner]

I like the idea about specialty bulbs. Actually saw one at Lowes the other day. The only REAL reason I want to do it is to get a better color anyway. (Plus, I am too cheap to do HID on my first light.)

[Dale]

You're right, I got it backwards. Brain fart, sorry all.

Fact is, resistance is quite low to start and rises after it gets warm. Yet another reason to electronically control if you are going to overvolt.

I personally don't like overvolting. I had once upon a time considered it, but was trying to come up with a way to either change heads or connect two heads underwater.

I'm going to build a DIY canister quartz halogen in the near future.

[SteveC]

The reason to overdrive a bulb is to get more light from the same amount of power. Halogen bulbs are designed to last for 1000’s of hours. This comes with a great sacrifice of brightness and color. In normal home lighting, power is not an issue, but in a dive light it usually is very critical. It seems to make since to take a bulb designed to last for 3000 hours, and overdrive it all the way down to 100 or so hours. That’s still a lot of diving on a $5 bulb.
I tried a 50 watt mr16 with my 3.5 amp canister light, and it only lasted for 10 minutes or so. I’m down to 35 watts for about 30 minutes, and am planning on dropping it to 20 watts. I’m hoping to overdrive it and get some decent brightness out of it, but since I’m using one 12 volt SLA, I’m not sure how I’m going to do it.

[JahJahwarrior]

That said, you do need a light that is reliable. A burn time of, say, fourhours is decent for a battery, HORRIBLE for a bulb. If you overdrive a little, that is understandable, but overdriving to the point that a bulb fails so quickly is pointless to me, as it is not practical.



And nowadays, you can realistically find a used 10 watt HID for $300. Infact, there was a guy selling an older one with SLA's for $150 on Scubaboard the other day, and a guy selling a DiveRite one for $200 on Cavediver.net. Granted, the lamps cost $150, but they have a 500-1000 hour life (1000 on average, some over, some under) and you don'tneed to worry about overdriving.



Also, "colour correctness" is somewhat arbitrary. The correct colour for a romantic evening might be a dim, underdriving halogen. The correct colour for video is more like a standard HID lamp (but for cars, you can get them in mulitple colour temperatures)