How to turn night into day?

Hello all, I'm trying to figure what it takes to turn the entire night into day. I don't just mean the area in front, I mean, as if the sun was right above my head and everything in front of me, to the sides, and so on would be immediately visible. Someone claimed this would take roughly 100,000 lumen so what kind of set up would I be looking at that would be the cheapest?

I have a battery pack that can put out 10,000 watts at a time, and it's a battery pack pack, and it seems that it should be possible to get at least 10 lumens/watt from that, so now all I'm looking for is the light. :twothumbs

ummm...i think you have watts and watt/hours confused, one is a measurement of power, and one is of energy. 10,000 watt battery is almost meaningless for anything other than finding out its ability to deliver volt x amps. This does not give us any inkling as to how long your battery will actually last. If its a 10,000 Watt/hour battery then it most likely is close to 500lbs (assuming they are lead acid as that the only economical solution).

Lets say you DO have a 10,000 watt/hour battery, then you could theoretically use 500 Cree XPG emitters all driven at about 575ma to get 200 lumens each. Assuming no losses in the driver(s) and we can even make heat and all that irrelevant, you would get 100,000 lumens, but only get 32 minutes of runtime out of 500 lbs of batteries. Using the first price I found for the XPG on google was 7.25 USD for bulk orders, so your order would cost you 3625 USD, and thats just for the bulbs. Now you have to buy wires and probably drivers and a GIANT aluminum disco ball to hook them all up to for you desired omni-directional beam...you are looking at a lot of money. 100,000 lumens is a whole lot of them...the price per lumen for anything over 300 lumens increases exponentially.

Oh...and i knew none of the above things 30 minutes ago when i started the post but with some searching and googling i figured them all out just fine...Not that i am upset, i love an opportunity to make my brain do gymnastics, but just saying you could have easily done the same. At first glance 10 lumen/watt seems easy until you realize we exist in a temporal universe and unless you want a 1 millisecond flash and your battery to melt we need to involve time...

swbluto said:

Hello all, I'm trying to figure what it takes to turn the entire night into day. I don't just mean the area in front, I mean, as if the sun was right above my head and everything in front of me, to the sides, and so on would be immediately visible. Someone claimed this would take roughly 100,000 lumen so what kind of set up would I be looking at that would be the cheapest?

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Well, if you want to reproduce the situation at noon, with cloudless sky at 21.06. , consider the following:

Sunlight has about 93 lumen/W.
Solar constant in the case above would be about 1250W/m^2.
So your source was right. About 115000 lumen. To illuminate a single m^2.
That means about 2 million lumen to light up a room.

If you want to recreate such an amount of light cheaply... well, there is just no way. Ever looked into the illumination used for filming /stages? You would need that times 10-100.

- Incan is out. If you would try to create that amount of light with halogen lights, you would be grilled by the infrared. (about 1kW on your body surface)
- HID would be WAY to expensive, plus at that levels you would need to take care about UV shielding for real
- LEDs dont scale that high, using 100s of normal ones would be too expensive, too.

You can always simulate the light level with a flashlight.

For examle, take a P7 Light with 500 lumen and put a ping-pong ball on the bezel.
The surface brightness of the ball will be a little less than when sun would be shining on it.

1 On a dark moonless night go to an outdoor area with some space, safety first!
2 Hold Fenix E01 above head.
3 Turn on E01
4 Shout loudly (and strongly) "LET THERE BE LIGHT"
5 Wait anywhere from 1 to 10 hours for the secret sunlight mode to enable.
6 Bask in the warm glow. The mode will be enabled for 8 to 12 hours.
7 Don't let your arm down until the light powers down. Severe burns could result if the light is lowered too early.

Let me know how it works out for you. :candle:

sylathnie said:

1 On a dark moonless night go to an outdoor area with some space, safety first!
2 Hold Fenix E01 above head.
3 Turn on E01
4 Shout loudly (and strongly) "LET THERE BE LIGHT"
5 Wait anywhere from 1 to 10 hours for the secret sunlight mode to enable.
6 Bask in the warm glow. The mode will be enabled for 8 to 12 hours.
7 Don't let your arm down until the light powers down. Severe burns could result if the light is lowered too early.

Let me know how it works out for you. :candle:

Click to expand...

Brilliant solution!! Can't wait to try it with my E01. :laughing:

Geoff

sylathnie said:

1 On a dark moonless night go to an outdoor area with some space, safety first!
2 Hold Fenix E01 above head.
3 Turn on E01
4 Shout loudly (and strongly) "LET THERE BE LIGHT"
5 Wait anywhere from 1 to 10 hours for the secret sunlight mode to enable.
6 Bask in the warm glow. The mode will be enabled for 8 to 12 hours.
7 Don't let your arm down until the light powers down. Severe burns could result if the light is lowered too early.

Let me know how it works out for you. :candle:

Click to expand...

That sounds as bogus as my unidirectional time machine. It travels forward in time, at 60 minutes per hour.
It's for sale, by the way.

First things first, I didn't confuse watt-hours. I don't care if it lasts for 6 minutes as my 1000 watt-hour pack would imply running at 10,000 watts. As you can see from http://www.hobbycity.com/hobbyking/...ame=Polyquest_XF_4400mAh_6S_45C_-_90C_Lipoly_ , 10C is nothing for these RC Lipo packs so no need to worry about melting the battery.

I first thought that a powerful sun-like omni-directional light would be ideal, but I think if it were possible to suspend the light by a giant balloon or something high enough, then only a 45 degree beam might be sufficient to replicate the sun's parallel rays. That could possibly reduce the needed lumen output to simulate day in the local area. This would just be like flares, except flares waste light in all directions.

In wooded areas, this may be impractical, but the distances would be short so omnidirectional lightly might be good enough.

While full day would be nice, I'd think I'd be satisfied with something less expensive and it seems the eyes adapt just fine to less lighting. At http://en.wikipedia.org/wiki/Lux , it rates full daylight at 10,000-25,000 lumens/meter^2 or lux, and it rates an overcast day at 1000 lux. It further rates office lightning at 300 or so lux, and so I think 100 lux would probably do it. I don't know how what the average square meters a given environment is, but assuming a sphere of 10 meters as in the woods, the area is 4pi*r^2 or around 1300 square meters. At 100 lux, that would come to 130,000 lumen.

So, what kind of lighting would have the cheapest "$/lumen" with driver and all? It seems halogens don't need to have a driver and they appear cheap compared to LED. But, oh gee, you worry me about the infrared and UV shielding required. It didn't seem to be an issue with "ordinary lights" nor the sun (assuming you had sunscreen on.), but the sun has ozone shielding and ordinary lights are low powered, so maybe that's why.

I'm thinking maybe I'll need to suspend the light in the sky somehow just so it doesn't bother others as much if it were on top of my head. That way, it would also ensure that the lux of it is sufficiently low such that radiation isn't that much of a concern (As opposed to the local hotspot if it were ontop of my head).

How large of an area/volume of real estate are you trying to illuminate? this is a key piece of information that you haven't provided.
What are the exact specs of the battery, in terms of volts and amp hours? Wattage by itself doesn't say much. I have found SLA cells to be EXTREMELY over-rated AH capacity when C of the application is greater than ~.5.

I don't know the area. :shrug: I was just hoping for something that would be useful nearly everywhere though given that I probably wouldn't use this in the city, I think it's safe to say the "woods". Or maybe hiking trails or something.

I'm thinking maybe I'll put this light ontop of a really big torch-stick. Here's something that claims 100,000 lumens at http://www.wolfedesigns.co.uk/lumin.html. It's powered by AC, but I assume Halide could be powered with DC voltages.

As far the battery, it's reconfigurable in whatever configuration I want. I can go high volts or low volts, it doesn't matter.

Perusing wikipedia at http://en.wikipedia.org/wiki/Metal_halide_lamp, it appears a metal halide lamp might be my best bet with an efficiency of 24% and 65-110 lumens per watt. That means I could probably get away with one or two bulbs running at 3 kW or less. (And a run time greater than 6 minutes!)

It appears that a vendor at amazon at http://www.amazon.com/dp/B000LPUHIE/?tag=cpf0b6-20 has 1000Watt bulbs for $50 each rated at 110,000 lumens. Other lower-end stores seem to want $200-400 for similarly powerful bulbs.
And reading online, it appears that halide lights typically have an outer glass limiting UV exposure so I guess it isn't as much of a concern as some made it seem.

perhaps you might want to go for the old style "torch" (think indiana jones) but instead of fire you use a couple CSM-360 chips from luminus devices at 6k lumens each, and then use the rest of the "torch" body for batteries and heatsinking? a diffuser or a large parabolic lantern type reflector may get the desired results...but your arm may grow tired from holding it up....also you may be interested in this thread if you really need over the top ridiculous lumens.

I may be missing something here, but you're saying you have a battery pack fill of LiPo weighing somewhere around 10kg. Eeeep!

I may be missing on the maths here so perhaps somebody could correct me if I'm totally wrong here...

I think the 1000W HIDs run around 30V, so would draw around 34A.

Assuming you reconfigure the cells as 8S (strap 2 of the 4S1P packs together http://www.hobbycity.com/hobbyking/...ame=Polyquest_XF_3700mAh_4S_45C_-_90C_Lipoly_ ) and you've got yourself near enough the voltage you need at 29.6V. 30A would be just over 8C, so you would be fine for about 7.5 mins at under 1kg of battery.

The battery packs I linked to are packing 54.76W each, so if you have 1000W I'm guessing you have the equivelent of about 18 of those packs for a total of 72 cells. Strap them up as 8S9P and you've got a pack packing a rather toasty 29.6V and packing around 33.3A ... now your 1000W HID is only pulling just over 1C and you have just over 1 hour runtime.

Downside ... not exactly easy to carry, and of course we've not allowed extra weight for any ballast etc. you might need to drive that HID.


Don't get your lumens and lux confused. The 100'000 lumen output is distributed over the area of the beam -in other words, lumens is a measure of the quantity of light, whereas lux is a measurement of light distributed over an area.

You can get a very rough approximation of lux at a distance by calculating the area of a sphere equal to your distance from the light. That makes some assumptions of perfect spherical output (non-existant, but not so wildly innacurate as not to be useful).

So for 1m
Areas of a sphere = 4*pi*radius^2
= 4*3.14*1*1 = 12.6 (1dp)
So 100'000 lumens / 12.6 = 7937 lux (ish)

At 10m...
Areas of a sphere = 4*pi*radius^2
= 4*3.14*(10*10) = 1256.7 (1dp)
So 100'000 lumens / 1256.7 = 79 lux (ish)

At 50m...
Areas of a sphere = 4*pi*radius^2
= 4*3.14*(50*50) = 94247.8 (1dp)
So 100'000 lumens / 94247.8 = 1 lux (ish)

At 100m...
Areas of a sphere = 4*pi*radius^2
= 4*3.14*(100*100) = 125663.7 (1dp)
So 100'000 lumens / 125663.7 = 0.8 lux (ish)


Food for thought no doubt.

Interesting matter...
I have tried to compare a flashlight to sun and found that I needed to hold even a bright flashlight pretty close to a wall or floor to perceive the hotspot to be as bright as the sun, I think it was less than a meter. And considering the sun is 150 000 000km from us and have no reflector it's a tremendeous impressing "incan bulb". Ever thought about if sun had a reflector? Highly hypothetically of course, but the hotspot had made our planet to an ash ball quite fast...

Regards, Patric

sylathnie said:

1 On a dark moonless night go to an outdoor area with some space, safety first!
2 Hold Fenix E01 above head.
3 Turn on E01
4 Shout loudly (and strongly) "LET THERE BE LIGHT"
5 Wait anywhere from 1 to 10 hours for the secret sunlight mode to enable.
6 Bask in the warm glow. The mode will be enabled for 8 to 12 hours.
7 Don't let your arm down until the light powers down. Severe burns could result if the light is lowered too early.

Let me know how it works out for you. :candle:

Click to expand...

Will this work with a similar light? Or will it annoy the sun gods?

1 kwh at 140 wh/kg is about 7 kg of batteries. I use it for my electric vehicle, so the batteries aren't an "additional expense" to me (If it were, though, it'd be quite expensive for light purposes alone).

UserName said:

That sounds as bogus as my unidirectional time machine. It travels forward in time, at 60 minutes per hour.
It's for sale, by the way.

Click to expand...

Does it have an "Off" button?

I've seen "night turn into day" when lightning bolts flash during thunderstorms.

and a cluster of sst -90s.

might take you a while to get home tho as your eyes will need to re adjust to the dark.

Cone hat with a 5lb ball of magnesium on top?

hmmmm....? this is probably a rhetorical question.

A 1000watt Metal Halide fixture draws over 9 amps at 120vac so it will be over 34 amps at 30 volts. It takes a few minutes to get to full brightness (added loss of usable battery power) and can you find a 30v ballast or will a very large 12v to 120vac power converters do the trick?

You want almost the equivalent of the suns output in a carry-able battery operated system = NOT!

Look at the night time street maintenance workers using a 4 x 1000w MH pole mounted light fixtures attached to a trailer with a generator. These are used right next to the work areas and has MAJOR shadows when you walk in front. You would need maybe 4 of these set ups to light an area of about 50'x 50' which isn't too large for an outdoor area. This may still not be the same as full sunlight.

Look how much light is used to light up a stadium. Use that as a starting point and calculate down until you get the size of the area you want to play in.


Njoy...