In the dark about lighting...

Simple answer is no and yes. You could make yourself crazy trying to find the figure this out because most manufactures use different formula's to arrive at their claims. The key factors are:
-Candlepower
-Degree of broadcast (20 degree being narrow to 180 degree being wide)
-Driver/energy consumption (you can drive ferrari at 5mph to save fuel but it still CAN go 180mph)

Typically, the greater the broadcast area the lower the intensity of light coming from a lamp with the same potential. Of couse the trade off visibility. Take a traffic light for example. You can see a red light from the LED version a long way from the intersection. However, trying viewing the traffic signal from the a 45 degree angle...get my meaning?

If the lamp is to be affixed to your head a focussed beam can re-directed to whereever you want to look. If you want to be seen a wider broadcast is required. Many of the new lamp combo's give you the option of two distinct lense/lamp combinations.

In your case, I'd recommend a good single light. Three lights, though positionable in three different angles, require you carry three light "housings" etc. and battery connections are more complicated.

Also, racing requires different considerations. Consider weight, durability and battery life. Think training bike vs. race bike.

Sorry, i'm probably no help.

csbakerrun said:

I am getting ready to do a 30 hour adventure race and I need a light to use during the mountain riding section of the course, the trails are single track and unfamiliar. My main concerns are price and light intensity.

I guess my main question is "do light sources add, intensity wise?" The reason I ask is it would be cheaper to get 3 - 1000 candlepower lights($45 a piece) as opposed to 1 - 2500 candlepower light($200). But, will three lights be as bright as one higher powered light?

Also what is the comparison between watts - candlepower - lumens?

Halogen vs. LEDs?

1 - bright halogen(say 10W) vs 3 - LEDs, three separate lights(say 1000 candlepower)?

"light me up", Baker

csbakerrun said:

I guess my main question is "do light sources add, intensity wise?" The reason I ask is it would be cheaper to get 3 - 1000 candlepower lights($45 a piece) as opposed to 1 - 2500 candlepower light($200). But, will three lights be as bright as one higher powered light?

They don't add "intensity-wise." Intensity and beam-width determine the maximum distance that the light will be thrown, and multiple lights won't add-up in that respect (but see below).

Having multiple lights means you can direct them in slightly different directions to illuminate a wider area, *or* use a more narrowly focused beamwidth (which gives greater sight distance) and still maintain some width to your field of vision. For your ride, you'll want to find a balance between sight distance and field of view based on the speed that you'll be travelling (faster means more sight distance needed) and the amount of obstacles that will be encountered from slightly off the path (lots of tree limbs and rocks means greater field of vision needed).

Heres a comparison of a few different lights that might help you out.

photobucket.comLight%20ComparisonOpen ↗

csbakerrun said:

Also what is the comparison between watts - candlepower - lumens?

Watts is the power drained from the battery - only useful when comparing light sources of the same technology and beamwidth.

Candlepower is light intensity at a certain angle. You can find LEDs that are fairly intense and cheap, but has a beamwidth of maybe 3 degrees. Such a small sweet spot is close to useless for a bike application.

Lumens is total light flow, which isn't that interesting either unless coupled to some angular information. An omnidirectional light source might have a high lumen rating, but used with a crappy reflector/lens etc the complete lamp will still only have an average performance.

csbakerrun said:

Halogen vs. LEDs?

Halogen is your basic light bulb technology spiced up through the use of halogen gas in the bulb. Light is good but a fair amount of the watts that goes into the lamp ends up as heat. From a bike perspective halogen can offer all the light you need as long as:
a) you can carry the batteries
b) you don't melt your reflector

LED's use a different technology altogether that don't waste that much energy on heat. (although high-power Luxeons does need special considerations not to overheat)
So far they're a bit restricted in light output, but the performance gap is closing fast and they offer better battery life for the same amount of light output than halogen does. Fittings tends to be smaller too.

If you are going to be riding on trails at night I'd have two lights; one on the bike and one mounted on your helmet. On twisting trails, being able to point the light in the direction you want to go is important.

LEDs will last a lot longer than halogens battery wise for a given output candlepower.

If you are lookign for endurance i suggest cateye ,

stick a couple of these on your bars, 30 hours lifespan and 1,000 candlepower each and uses AA batteries so you dont have to lug around a lead acid battery that you need with a halogen of the same power.

cateye.comviewProduct.phpOpen ↗

You see here is the problem now: "candlepower" is a useless piece of info because when stating candlepower you are allowed to select the brightest part of the beam and present it's lux measure in CP - even if it's a small artefact induced tangent of light somewhere in the beam that you wont really look.

"Lumens" is a better measure telling you the actual light output and "watts" tells what the light is producing in putput power but none of these - none at all tell you what your eye sees when you go "damn that's bright!"

that measure is the colour temp of the light weighted against it's lumens measured in Kelvin.
A classic example would be a 10w halogen VS a 10w WA HID, out the front of the reflector both are putting out around 500lumen according to the spectrometer but the HID is burning at around 5000 deg Kelvin VS about 2500 K for the halogen so even though they are putting out around the same light the one is crisp white and the other is a paltry yellow-orange.

the 6v halogens running on NIMH batteries are being under driven because of voltage sag under load and need to be overdriven by another 1.2v to get around 3200-3800K which is far whiter and more impressive, as these lights have 2000 or so hr ratings on them you will still get lots of life but less run time.

LED light by the way are really only good for being seen because as LED's do not have the red spectrum they will not cut through dust/rain/fog/smoke nor can they throw the light a good distance and finally they make it difficult to render colours thus harder to see. Yes they last longer run whiter and cooler but basically if you want to see they are [censored].

missionaryman said:

LED light by the way are really only good for being seen because as LED's do not have the red spectrum they will not cut through dust/rain/fog/smoke nor can they throw the light a good distance and finally they make it difficult to render colours thus harder to see.

You cant make white without a red component. White is the combination of red green and blue. Color temperature is determined by the different ratios of red, green and blue. White led color temperatures range from 2900K (lots of red) to 10000K (less red) depending on the binning. Without the red you would have blue, green or some combination of the two.

White leds are InGaN (blue/green) leds with single (high color temp) or dual (low color temp) phospher layers added to generate red light.

Steve_in_NH said:

You cant make white without a red component. White is the combination of red green and blue. Color temperature is determined by the different ratios of red, green and blue. White led color temperatures range from 2900K (lots of red) to 10000K (less red) depending on the binning. Without the red you would have blue, green or some combination of the two.

White leds are InGaN (blue/green) leds with single (high color temp) or dual (low color temp) phospher layers added to generate red light.

Good theory, useless for advice on what light to carry for a long bike ride. I reccommend a good HID light with a long-run-time battery, such as a Nightrider Rage light. You get a bright light that lets you see where you are going at speed. An Led light will seem bright enough until you are actually riding and you note you can't see that far in front of you, not far enough to avoid hazards, so you slow down. And with an Led light you have no side vision.

Basically you get what you pay for. And do not fall into the trap thinking you can get three Led lights for the price of one good HID light (you can't turn a pigs ear into a silk purse).

Rather than look on a forum here, check out web sites about bicycle touring. Some folks, like when crossing the desert, will ride only at night and they know from experience what lights work and what others are nothing but [censored].

For what it's worth, one of the local bike clubs that has evening rides, where the ride won't end until after sunset or around dusk require a rider have a light, but Led's are not allowed.

When it gets down to it, it can be really difficult to justify spending over $400 US for a light when you can get a Cateye Led light for $25. You can learn the hard way by using the Cateye lights. You can befefit from learning from others who actually ride at night and want to be safe.

Check out www.niterider.com
Check out other light systems as well. I am not so much pro-niterider, but when I was looking for a light to use as a commuter (which meant I would be starting a ride before dawn), I looked at all my options and chose the high-midrange of the niterider line. I looked at runtime, brightness, the size the battery , mounting options and such. The Rage model I chose happens to have Led's as well, so you can use either the HID or the Led.

I had the opportunity this last weekend to approach this question. While we make illuminated accessories/apparel, I still need lights to see where I'm going. I asked a friend (a manufacturer's representative) to offer some advice. As a result I got to try a 1/2 dozen different combinations on the road and on a hill trail near my home. I did not want to know anything about lumens or candlepower. I was going to try riding same line with these different systems and see which setup made sense to me. Each represented one of the best versions of their "type". All but one were from one company.

My totally anecdotal/non-scientific findings.

On the trail I was completely blown away by the HID system... I could really see where I was going...but the trade-off is carrying the monster of a battery or compromising with shorter battery life. I don't even need to tell you the cost of these systems. However, it was no contest in terms of illumination! There is no "stealth mode" with these units!

Straight, bar-mount LED's sucked! Head-mounted was actually worse as in tricky situations slight deviations in my head direction caused me to lose sight of everything in front of me.While on the road it was just okay where a greater level of ambient light allowed me to assess hazards in advance. At speed I felt that I needed more faith and better reflexes! What you sacrifice in a focussed beam you save in weight and energy consumption. However, I'd not feel comfortable riding in the middle-of-nowhere and have to rely on this type of set-up. As a back-up or secondary these were fine for trail. As primary on the road maybe, but not for me.

I actually liked a combo dual/lamp LED/Halogen head mount the best for the type of riding that i do. In low light the LED worked fine, while in the complete absence of light the halogen was superior and though it consummed more juice offered the sense of security that you need going down nasty trails you've not been down before.

The rep I got these setups from actually commutes with HID system and a bottle cage mounted battery, LED bike-mounted flashers and our lighted jacket...no he's not our rep.ha.

Bottom line, if I was on the trails for extended rides I'd invest in the HID, and have a LED/Halogen head mount as secondary. I've already bought the headmount unit (full retail).

yeah basically you're not going to beat HID for light output and clour temp - even though it's expensive it really eclipses everything else.

I think it's funny how people immediately switch off when confronted with the scientific approach, saying "I want to buy a light but I don't want to know anything about lumens or candlepower" is like saying "I want to buy a really light frame but I don't want to know about kilos or pounds".
See you could go and ride with each light and yes it would be fun or informative but then again you could save yourself the effort - Good LED 120 lumens - good HID 1850 lumens. Well maybe that's just me - I always prefer the scientific approach.

My solution is that I have built my own light - it's a modified 2C maglight held on by a twofish cyclopblock and puts out 700+ lumens (34watts) (same as a 10w HID) with a close to daylight colour temp. It's brighter than the headlights on some cars and I can flood for low speed/close range or spot for high speed/long range.
It runs for 1hr on low beam (500lumens) or 1/2hr on high beam without a sattelite battery pack and weighs less than one pound. Total cost to me was $220 Australian currency including the rechargeable lithium batteries & charger - for the money NOTHING even comes any where near close to it and I can dismount and carry it as a torch.

There is some good information here.

Now a bit more to add to the confusion.

Lamp lumens = total lemen output of the lamp

Total Lumens = the total lumen output of the luminaire(torch, bike light, streetlight, etc.)

Light Output Ratio (LOR) = the % of lamp lumens which make it out of the luminaire.

Lux = total light hitting a surface.

Colour temperature = colour appearance of the light. 2700K is incandescent and halogen. this does not change unless under volting. covering all the colour spectrum.

all other colour temperatures are apparent. made by approximating the colour output on the spectral distribution plane. these are produced by peaks and troughs in the visible spectrum. 2700K from Halogen lamps is NOT the same as 2700K in HID.

Colour temperature does not affect output, colour rendering or ability to see. A 20,000 lumen lamp is 20,000 lumens no matter the colour temperature.

Efficacy = Lumen/Watt. This is the best measure to use. a 20W Metal Halide lamp will consume ~24W (including control gear.) this is far superior to a 20W halogen lamp. as the lumen output is higher. The catch is heat. you need a far better reflector/lens system to harness the light. LED may have a good efficacy but as the lumen output is low and very directional they dont work for penetration very well.

High output LED's generate alot of heat. the Luxeon Star has a large heat sink on the back which, according to the instructions, must attach to another sink and be mounted away from other Stars to attain full output. Also, the full rated output is for a short time before the LED reaches end of life. One hell of a good LED though.

Only under driven or low wattage halogen will be at 2700K the light in my reply above is rated at 3900K - daylight is about 4200K which is the starting point for most HID systems, people like to take them beyond that thinking they are getting a better output but from about 6000K on it just gets blueish.

After testing various lights it was found that the loss through a reflector & lens is about 35% hence the 700L figure on my light - the rated bulb lumens at 4.30AMPS is 1150L. The light is very white not like normmal Halogen or Incans, bulb life is reduced to about 100hr from the std 2000kr @ 6.0v

Hillman 531 said:

There is some good information here.

Now a bit more to add to the confusion.

Lamp lumens = total lemen output of the lamp

Total Lumens = the total lumen output of the luminaire(torch, bike light, streetlight, etc.)

Light Output Ratio (LOR) = the % of lamp lumens which make it out of the luminaire.

Lux = total light hitting a surface.

Colour temperature = colour appearance of the light. 2700K is incandescent and halogen. this does not change unless under volting. covering all the colour spectrum.

all other colour temperatures are apparent. made by approximating the colour output on the spectral distribution plane. these are produced by peaks and troughs in the visible spectrum. 2700K from Halogen lamps is NOT the same as 2700K in HID.

Colour temperature does not affect output, colour rendering or ability to see. A 20,000 lumen lamp is 20,000 lumens no matter the colour temperature.

Efficacy = Lumen/Watt. This is the best measure to use. a 20W Metal Halide lamp will consume ~24W (including control gear.) this is far superior to a 20W halogen lamp. as the lumen output is higher. The catch is heat. you need a far better reflector/lens system to harness the light. LED may have a good efficacy but as the lumen output is low and very directional they dont work for penetration very well.

High output LED's generate alot of heat. the Luxeon Star has a large heat sink on the back which, according to the instructions, must attach to another sink and be mounted away from other Stars to attain full output. Also, the full rated output is for a short time before the LED reaches end of life. One hell of a good LED though.

According to the manufacturers, Osram, Philips, etc.....

Incandescent ~ 2700K - 2900K

Halogen same, it only emmits a higher intenstiy through the halogen cycle. Incandescent can only emmit one colour temperature as it is caused by heating a wire. the colour appearance can be changed however by tinting the glass envelope, hence the blueish halogen lamps you see on some cars. (discounting the Xenon discharge lamps of course.)

Warm White 3000K
Cool White 4000K - 4200K
Daylight 5000K - 6000K

here's a beamshot at 1.5" exposure in a completely dark room - it is so bright at normal "as the eye sees" setting that you can't make out the towel in the hotspot from 2 metres. - that aint 2700K...

I repeat the room is completely dark and there are no lights on and next to nil natural light.
Beamshots are normally taken against a white back ground to enhance how bright they look - I have done the exact oposite by using a matt brown door and matt brown walls as the surrounds. I'll take a "real world" photo from my bike tonight - this is definately not a 2700K orangy light.

If you go to the Welch Allyn on line store and look at the details of some of their halogen bulbs - say the WA01185-U for example you will see the colour temp is 3370K here's the link: walamp.comdetail.tplOpen ↗

I also have a 3C bike light from this bulb which puts out about 800L with a correlated colour temp of 3473K - cars high beam me when I turn that one on so it's really only for back streets.

I never had a filament break either so far and it's pretty bumpy in places.
Next to HID or Luxeon LED (you have to look hard to find the Luxeon next to my beam) it still looks a bit yellow but next to other halogen bike lights and even car headlights it looks white so it's somewhere in between - just like the Kelvin figures would suggest.

Here is the key..... Correlated colour temperature.

instead of tooing and froing,,,,, Linky

1. watts: power consumed, provides rough estimate of output for comparison
   
2. candlepower: intensity, determined by overall output and beam pattern, can often give misleading comparisons
   
3. lumens: overall output
   

There are 2 distinct technologies that fall under LED: 5mm LED (what most people think of when they hear "LED"😉 and high-output LED ("Luxeon Star" is the most commonly used type). In my opinion, neither LED is worthy of consideration in a retail light. 5mm LEDs do not have enough raw output, and Luxeon-based lights are grossly overpriced relative to their features and alternatives (actually, all bike lights may be, I just know about the Luxeon ones) - passable ones start at $100 and up.

I think you should determine your budget first, then attempt to choose your lights. If you're not convinced that you should budget as much as you can afford, you should buy a cheap ($15-20) light and scare yourself riding with it (please be careful). As someone mentioned, the quickest way to find that your light is inadequate is to take it for a ride.

As missionaryman has been posting, custom halogen (especially if you build it yourself) is likely to get you the best lumen/$, at the potential cost of bike-specific features. You have to budget time to have it built.

Here is a bike light that I modified with 2 Luxeons 2 years ago. Cost for all parts (counting original light, a worthless POS, and heatsink, which I got for free) came in under $80. I think it's barely sufficient for street riding (contrast that with how bright the beam appears in the photo).
candlepowerforums.comshowthread.phpOpen ↗

Regarding whether white LEDs produce red light - red light is emitted, but at less intensity than other wavelengths in the spectrum. There is a Lumileds diagram (lumileds.comAB15.PDFOpen ↗, page 3) that shows a fall-off in the reds for a "typical" (unspecified color bin) white Luxeon. I've read posts (flashlight forum, not cycling forum) where people have taken their Luxeon lights off-road and found that, despite being perfectly fine on the street, the lights do not illuminate the browns of dirt and tree bark sufficiently. The suggested solution was to add a Red or Red/Orange emitter, but I didn't read anything about that.

Thanks Flatscan, you're obviously a little smarter than me when it comes to this stuff but on a similar wavelength. here a re some beamshots from the handlebars:

At 11m from the tree and about 25m from the house accross the road - looking into a streetlight:

Around the side of the house the beam is illuminating an area of 4m wide by 13.6m long:
[img]i82.photobucket.comROP HOLA beams003small.jpgOpen ↗[/img]
Coming into my driveway from about 6m away:

all pics are 1.5" shutter speed.
There is nothing around for the price which offers both the practicality and illumination level of this light. $250 - Australian dollars.