Home lighting

[Prune]

I'd like to simulate daylight in my room. What's the best option? I've seen some fluorescent bulbs with 5500 K and Color Rendering Index of 96, that are also inexpensive, but they are not bright enough and I'd need half a dozen. On the other hand, types such as metal halides and arc lamps are brighter but quite expensive (and what about life?). So what are the best approaches, in both cases (cost is and is not an issue)? No, I don't care about efficiency. I need about as much brightness as provided by a 300 W halogen light.

Also, all of these do not show a blackbody curve. Are there any light sources that actually have a material at 5500 K and produce an almost perfect sun+skylight spectrum?

[Edit] I also came across those SoLux bulbs that have CRI 98-99, but they are only 12 V! Maybe if I put ten in series...

[tom daghdha]

What about Metal Halide (mercury vapour) bulbs? We have those in a hall and they kick out some intense daylight.

[Geek]

Check out a larger photography store, like Lens & Shutter on Broadway there (I think the biggie is on Broadway). They had some 2nd hand lighting that'll probably fit your needs for decent price

[Krist]

If i remember correctly mercury vapor, metal halide and most other HID bulbs last about 2-3 years. I don't know how long the ballast will last but it probably depends on the quality of the capacitor used. If you plan to grow stuff under the lights metal halide or high pressure sodium is a good choice. I have 2 chili peppers and a paprika plant that are growing fine under a 50w sodium light. Otherwise don't use sodium, they have a really low CRI (really annoying when trying to read resistor values).

[Prune]

I'm not growing anything. I just work better and feel better under natural sunlight. Being that I live in a basement suite, and winter in Vancouver is six months of gloom, I was looking for something that closely mimics sunlight.

[Mike Gergen]

You have multiple options. Living in Mpls also with 6 months of gloom I understand...

Go to your local pet store, a good one. Look at VHO flourescent lamps, power compact flourescent lamps or HID metal halide. They all come in 5500K Color temp and the HIDs are also available in 6500K and 10,000K. These lamps are used over coral reef aquariums in which CT and light output is critical.

Both types of flourescent lamps require a special ballast, an Icecap or similar although they can be run from a big tar ballast it isn't recommended due to heat and efficiency.

VHOs have 3-4 times the light output of a normal T8 or T12 lamp. Power compacts have even more.

All have pluses and minuses;

The VHO is available with different CT. They need a special ballast and fittings due to the amount of current they take.

The power compacts the same but they don't have as many options for CT as the VHOs do.

HIDs are the closest you can get to natural sunlight. But remember that a 5500K sunlight rating is outdoors at high noon on a clear day at lower latitudes. The issue with HID is that they run HOT. They get 5500K CT by running the lamp at close to that actual temperature.

Flourescents are better at a more even light but can resemble an office building too much if not done correctly.

HIDs can create a point source of light with the right fixture. You can also use a uplight fixture which will give you a diffused lighting set up. HIDs also have an issue with start up. They take 5-10 minutes to light up completely and if they are already hot they will take longer.

All these lamps are available through most electrical supply houses but go to the pet store first to find out what is available in your area. None of these lamps are cheap. For a good HID lamp you may spend >$75 US for one bulb.

The life expectancy of all these lamps is close to 10,000 hours but is really determined by the ballast used. The lamps are rated at a half life. Meaning that after X hours the light output has dropped by Y%. This shouldn't be an issue for what you want to do. The ratings are there for the aquariust so he/she knows when to change them.

I've been using VHOs over my aquarium for years with an Icecap and have been very happy with them. They run 12 hours a day and get replaced once a year. The Icecap has never given me a bit of trouble and I've had it for 8 years.

Good Luck
Mike

[Prune]

Interesting graph:



The problem is, the SoLux only go up to 50 W, and run on 12 V which means transformers.

Would there be any problem if I put these in series so I can run them directly off the mains? What makes me ask is that filaments change their resistance depending on temperature, so I don't know if a series connection will work correctly.

[Mike Gergen]

You mean 10 of them in series?

[hacknet]

they would probably work if you string 20pcs in series for 230v or 10 for 115v supply

[Prune]

Filaments have very low resistance when cold, but current through them decreases and reaches some constant value as they reach operating temperature. The issue is whether I can get the same operating temperature, because color depends on that.

It's such a simple idea that I'm surprised nobody used it before. These lights have vertical filaments so most of the emitted light goes to the reflectors, which have many layers of different minerals adjusted to match the solar spectrum.