24v 250w lightforce 170

[Busa Rush]

hello fellow light people..

I am a truck driver from the uk and have a lightforce 170 lamp for which i use in the cab etc for different things.. the truck has a 300w 24v supply cig lighter.. so out went the 12v bulb and now has an osram HLX 64655 250W 24V bulb in it.. i also modded the switch to a 20 amp item.. the other one would have melted i am sure!.. i only use the lamp in short bursts 10 15 secs max.. it's great for finding trailer numbers etc in the yard.. the security bloke was wandering in the yard last night just gen checking around and had is little lamp on the doors etc.. i lit him up like a xmas tree he had no idea what was going on! it was so funny and also having general fun and messing around and lighting up stuff very far away! it is very good at making people coming the other way on the road dip their main beams! am not too hot on electrics but know the basics.. love to learn etc and mess around.. i have on order the 240 reflector.. so am looking forward to that.. don't know what the CP is on this anyone know?.. but is very very bright! will take some pics when i get it..

this forum is great.. i think i will look at getting a hid torch for gen checking over the truck and trailer at night also.. any tips on what would be good for that?

got a couple of pics on my webshots page along with my car.. for those of you into cars.. it's a bike engined sprint car hayabusa..
http://community.webshots.com/user/BUSARUSH
thanks in advance

cheers

Dave.c

 

[Lurveleven]

Hi and welcome to CPF,
the 64655 bulb should give you 10000 lumens (unless the actual voltage to the bulb is less than 24V) which is more than any available HID I know of. I don't know what the CP will be but it should increase with the 240 reflector. The filament on the 64655 bulb is large so a HID with lower lumens may outthrow it. If you want max throw then you need to take a look at MaxaBeam.

Very cool car btw!

Sigbjoern

 

[Ra]

Hi Busa, I can tell you some more about CP's: The amount of lumens a lamp produces doesn't say anything about the candlepower output you would get when you put it in a reflector. For that you need to know the surface brightness of the lightproducing part of the lamp: the filament ,or if its HID: the discharge-arc.

Here it comes: the average surface-brightness of halogen is about four times lower than HID. The lamp you use is a projection type bulb: it has the highest surface brightness possible using halogen, but still about 1/3 of HID.

The lamp you use indeed is rated at 10000 lumens, very impressive. But I think I must dissapoint you as it comes to CP-output when using a 240-reflector: You will get about 1 million cp at the most depending on the supply-voltage.
When you replace your bulb by 35watt HID you would get about 3million CP's,
but with 3200 lumens much less impressive light output!

Maxabeam puts out 6 million cp's using an even smaller reflector (120mm diameter), but produces a very narrow beam at 6 mcp. And with 1200 at the most, lumens output of MB is very poor.

Another problem using HID is that its not instand on, it needs time to startup (15 secs or so). So blinking is way not as impressive as when you use 250watts of halogen! On the other hand blingking HID with a hot bulb is very impressive: LIKE LIGHTNING (and I know: I have HID high-beam!) but it's very bad for the burners, it drasticly shortens bulblife. But with HID you can lose a few hours: The bulblife of your 250watt-bulb is about 50 hours at rated power, the averge HID bulblife is about 3000 hours!!

Regards,

Ra.

 

[Orbit]

agreed with RA.

 

[Busa Rush]

Thanks for the replies chaps..

Ra you say i would only get about 1M cp? this is what lightforce claim to get with the standard 240 blitz lamp.. and i am using a bulb 2.5 times brighter? I also have a 300w bulb i have sourced.. should be with me next week along with the new reflector.. will try and take some pics..

still trying to learn all the science behind it all but all good fun .. here's a link to the 300w bulb i ordered ...

http://www.servicelighting.com/catalog_product.cfm?prod=GP15503

cheers for now..

Dave.c

 

[Ra]

Hi Dave, 1 Million CP is not what the manufacturer claims: Its what I calculated to be possible using the 250watt halogen bulb you mentioned with the 240mm reflector !

I hope I can make you understand that a brighter bulb does not mean more cp's, its even well possible to have a brighter bulb that puts out less cp's with a reflector. Bulb brightness (lumens) and surface brightness (generating cp's with a reflector) are two totally different things.

Ra

 

[Busa Rush]

Hi Ra .. getting there.. I understand lumens.. could you explain to me about the surface brightness (generating cp's with a reflector).. on me night off am going to have a good look on the forums here and try and learn all i can don't want to pester you with q's.. i believe eveything you tell me.. it's just i need to understand a bit more..

I took some pics tonight in the trailer yard with me lamp.. the cam is a nikon coolpix 3100 i had it on night mode so it's a bit grainy.. not great pics as i had the lamp resting on the cab window with the cam on top.. bit awkward.. I have not messed around with pics they are as they are.. hope you will give me and honest opinion... will take some more when i get the bigger reflector and 300w bulb sometime next week..

http://community.webshots.com/myphotos?action=viewAllPhotos&albumID=552795137&security=nGSSCi

cheers

Dave.c

 

[Ra]

OK, : Surface brightness for throwguys, lesson one:

This:

Is as bright as this:

(only the colortemperature is a little different, but thats another story..)

But compared to the halogen bulb the fluorescent bulb has a huge surface, it needs that entire surface to generate 10000 lumens !!

So lets look at the amount of lumens comming from 1 square mm: The fillament of your lamp (hlx64655) has a surface of 25 sq mm, generating 10000 lumens. That gives 400 lumens per square mm.

Now I really don't know how big the surface in on that fluorescent bulb is but my guess is well over 15.000 square mm !! So that gives 0.67 lumens/sq mm.

So your lamp has a surface brightness 600 times higher than the fluorescent bulb.

Now we put those lamps in a reflector (I mean theoretically...) The reflector reflects the light to a point at infinnity. But here it comes: One of the laws of light says: The apparent surface brightness of the reflector cannot exeed the surf.br. of the bulb. In fact it always is lower due to the fact that the reflecting surface of the reflector does not give 100% reflection!

So looking into the two reflectors from a distance one seems to reflect about 0.6 lumens per sq. mm, the other about 360 lumens per sq.mm !!

So lets assume for a moment you're using 240 mm diameter reflectors for both lamps: Looking into those reflectors from a distance, one reflector appears to throw 2750 lumens at you, the other 1,650,000 !!!!!

So tell me.. which would appear to look brighter ???

BTW: Theoretically I'm not allowed to use lumens here, I should convert to candlepowers before using a reflector, but that probably would make things harder to understand. Be ware of the fact that a reflector does not increase the lumens output of a lamp! it only directs most of the light produced by the lamp to a smaller surface.

If you have any questions about this, don't hesitate to ask..

And... nice pictures BTW...

Regards,

Ra.

 

[Busa Rush]

Hi Ra ..
they would both look the same?

if the total brightness of the bulbs are the same? so the total light would be the same? prob got this comp wrong .. I will get there i am determined..

thank's Ra

Dave.c

 

[Ra]

Let me try this another way: If you would put your lamp at the midlle of the room, with or without a reflector, it will light up the room with the same brightness as the fluorescent lamp would: the lumens outputs are the same.

But if you want to use both lamps with a relfector to obtain throw and illuninate objects far away, then you will see a huge difference in performance due to the difference in surface brightness of the lamps!

Another example: I've modded two Thor spotlights: One with 35/50watt HID, and one with Mercury-short arc (super high surface brightness!)

I placed both spotlights in the field and photographed the difference in apparent surface brightness: (forget the smaller lamp in the middle:that is Maxabeam)...

This picture is taken using a very dense welding filter: otherwise the chip of my camera would become smoking hot !!

So you see the faint contours of a big reflectror on the left: 50watt HID.
Very bright reflector on the right: mercury-arc Thor.

Now I'm asking you the same question as before: Which spotlight would look brighter from a distance ??

NOW HERE IT COMES (AGAIN !!..) With 5000 lumens the HID torch (remember: its the faint reflector!) has close to twice the lumens output compared to the mercury arc! But the surface brightness of HID is much,much lower than mercury arc! So with 2800 lumens, the mercury arc throws way, way further (It throws more than 4 miles !) than HID with 5000 lumens !! (HID throws about 1 mile !!)

Many lumens with lower surface brightness gives less throw and broader beam.
Less lumens and higher surface brightness gives higher throw and much (laserlike) tighter beam.:

Beleve me, you cannot possibly do this:

With your 250 watt halogen: you would need a 1.5 meter diameter reflector...

The reflector I used to create this beam is 220mm diameter..
with a lamp putting out 2800 lumens, much less than your 250watt halogen!

Regards,

Ra.

 

[Busa Rush]

Hi Ra .. cannot see pics just a little red X in a white box.. off to work now.. can you pm the pics? or are they in a different post on the forum anywhere? when i get back later will read it all up and will try and make head of it.. I will get it in the end.. got the 300w bulb today so will see what that does tonight @ work
am understanding a lot more of what your telling me now

thanks for your time..

kind regards

Dave.

 

[morelightnow]

i don't know about busa, but i just learned a lot. now i can build my lights with a better understanding of how to get the results i want. just like building high performance engines. thanks ra!

 

[Busa Rush]

Hi Ra..

think i got it now.. your mercury arc monster would be the one as it has the long throw and almost laser like beam compared to mine.. manged to find a pic on the other posts.. still can't find the ones you posted on here tho..

Many lumens with lower surface brightness gives less throw and broader beam.

this is what i have and it suits my needs just right.. like a very powerful landing light..

Less lumens and higher surface brightness gives higher throw and much (laserlike) tighter beam.:

as i understand this.. hid and your merc bulb .. very small tight light source about the size of one of these icons? :huh:

now tonight i put the 300w bulb in the lamp.. it has less of a spot now more like a tight flood but a little brighter not by much tho.. very pleased with it and will see what it's like with the 240 next week..

the CP i know a little more now.. after seeing these 10 15 MCP lights i thought mine would up there with them.. didn't know a lot of these claims were not true.. and you measure the CP in the spot part of the beam yes? this explains to me now why your modded thor and the other types of merc short arc are so bright at distance.. so CP now is irellavent to me .. hope i got it ok? :lolsign:

thanks again..

Dave..

 

[Ra]

Yes Dave, you got it right!

One thing tho... the size of the arc in my Maxablaster is about 0.13 square mm !!! So those icon's are way, way bigger!!!!

Imagine 0.13 sq mm putting out 2800 lumens !! Let me tell you.. Its impressive!
And that immidiately brings along one of the hazards playing with those lamps: Lookling into the arc without eye protection (type 13 electrical welding filter!!!), weather it's directly or via the reflector, can cause SEVERE DAMAGE TO YOUR EYES !!!

The HID-arc of the commonly used 35 watt automotive burner has a surface of approx 4 square mm: so even that is much smaller than those icon's!! But its much less harmfull to your eyes than mercury-arc. But beleve me, even here, If you set your mind to it you can damage your eyes !!

BTW. I don't know what brand the 300watt bulb is you're going to use but remember that the 250 watt bulb you have now is top (I mean really top!!) of the line in both lumens output and surface brightness (in the halogen world ofcource..) So chances are that the 300 watt bulb is not capable to top that!!

Laterrr,

Ra.

 

[monkeyboy]

Thanks for explaining that Ra.

So, in short, candlepower is a measure of beam intensity (i.e. throw) which is dependent on surface brightness and the reflector.

Do you know how the candlepower scale is defined? Is it beam intensity at a certain distance?

 

[Ra]

Yes, Monkeyboy:

In fact: If you're in the possession of a lux-meter, checking the candlepower output of a torch is simple: Measure the distance from the reflector to your lux-meter: lets take 10 meter for that..
Measure the output of the torch: lets take 200 lux for that..

Calculate the CP-output: 10 x 10 x 200 = 20,000 CP's

The light is a radiation following the inverse square law: when you double the measuring distance you will get 1/4th readout:

So at 20 meters you'll probably measure 50 lux with the torch mentioned above:

20 x 20 x 50 = 20,000 CP's

Indeed you should measure the CP value for the brightest (middle-) part of the beam: only that is responsible for throw.

IMPORTANT:

To get a reliable measurement you first must determine the minimum distance at which the entire reflector is lit by the filament (or arc!). You can use a welding filter (type 10 minimal) to do this: simply look into the reflector from a distance:

Is only the central part lit, you're too close, or your torch is not optimally focused.

Is only the outer rim lit: Then your torch definitely is not optimally focused!

Some torches do not have reflectors that can be lit totally: too many imperfections in the shape of the reflector !! Here you will have to collimate the best you can..

Lesson 2: Lumens v. candlepowers: Each lamp (without reflector) produces an amount of lumens in almost all directions: here you can determine the approx CP-output of the bare bulb: Lets say the bulb puts out 3000 lumens:

To convert to CP: 3000 / (4x Pi) so: appr 239 CP's

The CP-value of a bare bulb without reflector is called MSCP: Mean Spherical CandlePower

The CP-value of a beam (bulb with reflector) is called BCP: Beam CandlePower

Lesson 3: You now can calculate the theoretical CP-output of a torch:

Lets take the lamp mentioned above: If its HID, it would have an arc-surface of about 4 square mm: its putting out 239 MSCP's: thats about 60 CP/mm
This is the surface brightness of the arc.

Dimensions of the reflector: Lets take a clear aperture of 100mm and a center hole of 15mm: calculate the surface: (100/2)x(100/2)xPi:
7,853 square mm.

Hole: (15/2)x(15/2)x Pi: 177 square mm.

So the surface is: 7,853-177= 7,676 sq. mm

(this is the aparent surface seen from a distance so 2D, not the actual surface: ofcource the surface is much bigger due to the depth of the reflector, but that is not an issue here)

Calculate the CP output: 7,676x60= 460,560 Beam CP's for the torch..

But we're forgetting something: NO WAY THE REFLECTIVE MATERIAL REFLECTS 100% OF THE LIGHT !! Mostly thats more like 80% or so

So 80% of 460,560 BCP is: 368,448 BCP's

Infact the example I took is commonly used: its a 35watt automotive HID-burner with a 100mm diameter reflector (McCullog X990)

So if you understand the above you'll know that NO WAY THE X990 PUTS OUT THE 7 MILLION CP'S THE MANUFACTURER CLAIMS.

So, Monkeyboy, can you find the answer to your question in the above ???

Regards,

Ra.

 

[rufusdufus]

So with 2800 lumens, the mercury arc throws way, way further (It throws more than 4 miles.

Ra,

Thats the performance i'm after.

I can't see 4 miles, but with binoculars I can see a lot further.

Also my camera can see much further than me(especially on time lapse in little light).

Any link to your mod?

If not would you care to elaborate(with great detail and suppliers please).

Warwick

 

[Ra]

Hi Rufusdufus,

Link: http://candlepowerforums.com/vb/showthread.php?t=125819

Ra.

 

[David_Web]

Ra

I have been thinking about this for a little while.

Doesn't the inverse square law ONLY apply to a point light source?
Think about it, take it to the extremes and take a laser. Now that would not drop off to 1/4th the brightness if you double the distance.

Could you test this and see if it does or not?

And your explonation was one of the best I have ever seen. It was acually your post about your Maxablaster that made me realise and understand "throw".

 

[Ra]

Hi David,

I hope you understand this: Every light, spotlight, candlelight or laser: as soon as the entire aperture of the source is used, (entire reflector is lit looking into it from a distance) the light follows the inverse square law.

But if you are too close to the reflector and the reflector is not totally lit its not following the inverse square law.

Example: My Maxablaster gives the same readout in the brightest part of the beam, weather its at one foot or at 200 feet distance because its not using the entire reflector in that range: Step by step towards 200feet it uses more and more of its reflector till it is totally lit at 200 feet. Over 200feet distance the lux-readout is dropping following the inverse square law.

With a laser its the same story, only the laser has no reflector, it has a lens, but in basics it's the same!

Regards,

Ra