Bike Light: LED vs. Halogen

I am using home made 20w halogen bike lights and would like to replace them with LED's to increase run time. I usually use one 20w, sometimes two at once. My battery is a 14.4 LiIon so I am overvolting the lights. Two lights at once puts out quite a bit of light so I am spoiled. What kind of LED arrangement would get me equivalent light output?

Thanks

Hello sv ted and welcome at CPF

I guess a 20W halogen bulb will output about 500 bulb lumens.

So an arrangement of 4xU-bins or 3xW-bins, driven at specs, should be fine.

But you can't get a hotspot like the halo-bulb.


Best regards

____
Tom

HID is the most efficient bike lighting system available today.

Lots of options/makers... all have super beam spread and ultra-long runtimes.

Google it.

Cheers,

If going the LED route, it would be far more cost-effective to go with non-premium LEDs, such as T-flux Luxeon 3s and gang 8-12 into a single device. An advantage of using more LEDs is you can experiment with a combination of optics and reflectors and dedicate individual LEDs to particular tasks - ie use 6 for close-up flood, 4 for medium spot, and 2 for narrow spot ... or whatever combination works best for you.

With a 14.4V Li-ion, you can make strings of 3 LEDs and use a resistor or some sort of buck regulator. There's also the option of dimming your light source - LEDs get more efficient at lower drive levels.

HID is definitely more efficient than LEDs ... for now. It will scale into the kilowatts if you're so inclined. HID is also a bit more expensive since the lamps are high-voltage, high-temperature, and high-pressure...

Trailtech makes some inexpensive self-contained HID units. The 30W unit claims 1850 lumens while I would expect 500-600 lumens from the 13W units.

idleprocess said:

If going the LED route, it would be far more cost-effective to go with non-premium LEDs, such as T-flux Luxeon 3s and gang 8-12 into a single device. An advantage of using more LEDs is you can experiment with a combination of optics and reflectors and dedicate individual LEDs to particular tasks - ie use 6 for close-up flood, 4 for medium spot, and 2 for narrow spot ... or whatever combination works best for you.

Click to expand...

That's a good suggestion idleprocess:thumbsup:

Best regards

_____
Tom

Thanks for the suggestions. I would prefer LED to HID because of the cost of bulb replacement for the HID. I don't know much about them but saw replacement bulbs at batteryspace that sold for $85!

I am going through the same decision, but I am stuck with using off-the-shelf systems.

From what I can see, the only LED system that has been reviewed with beam shots so that you know it will come close to your 20W Halogen system is the Cat Eye Triple Shot, which is hugely expensive, and does not dim to a low beam. Just on and off.

In Canada, Nite Hawk has just started producing a K2 model, which is supposed to be the equivalent of 15W Halogen, off of a 4xAA Nimh custom battery pack with smart charger, for a total weight of 1.2kg, cost $159Can at MEC.ca in their new winter catalogue, p. 25 More info will be out on it in Oct.

I have used Nite Hawk's less sophisticated single LED Emitter system and find it just barely enough for pitch dark, no streetlights cycling. I usually use a 12W+20W Halogen helmet-belt-pack system which is down as the nicad pack has died after 3 years. I do find it heavy. However, it works
just great at -40C which one cannot say of that many things....

I may hedge my bets and get a new nicad pack for my existing system, and wait until better reviews are available for K2. I will let you know!

enlightenment!

Here is a problem you are going to run into... an overdriven halogen is more efficient than an overdriven LED... the highest efficiency LEDs are more efficient than over driven incan.. only when not over-driven... which means.. to get more light (runtime) and the same amount of light you need a bazillion (maybe with 15-20) emitters..

If you really want more runtime... get your efficiency maximized.. add another cell to your pack to go from 14.4V to 18.0V..


some examples.. an osram 20W 1149 (model) lamp run from a 14.4V source direct-drive with an estimate 100mohm resistance.. (for switch and wires).. will get 14.22V to the lamp and get you 568 bulb lumen and 369 torch lumen... that is a mere 21.8Lumen/watt.. and say you have a 2.2AH (presuming 18650 cells).. you'd get 1.2hours runtime..

take the battery pack and add one more cell to get 18.0V nominal.. and run an osram IRC lamp.. take the smallest lamp they have.. 25W model.. and you get 17.74V to the lamp and the output is 1436/933 lumen.. with 30.7 lumen/watt! (40% more efficient).. now this is a lot more power, so your runtime would be lower, so it's not the best solution for your cause..

however...

you mentioned using 2x20W.. if that is the 12V rating than at 14.4 you are pushing 26W each or 52W.. you'll also be getting a net output of maybe 738 total lumen.. whereas.. running a SINGLE '25W' IRC lamp from 18V the energy cost is 46.7W and you get 933L.. so.. 26% more light and longer runtime..

if you want to have extended runtime.. you could have a low-output lamp in one of your headlamps and a high-output in the other... however.. it's very tricky to find lamps that will run at the same votlages and include the ludicrous efficiencies of the IRC lamps... i'll note.. that the 25W IRC has only about the same efficiency as some normal lamps.. so let's look at another solution:

the osram 64610 lamp.. runs very well from a 14.4V source if you regulate the output to 13.0V.. The numbers look like this:

62W.. 4.77A.. 1376 TORCH lumen... it's a knockout!... but there are other lamps that will run nicely from a 14.4V source and still have a high efficiency..

the 1166 lamp.. i run it at 12.5V.. 35.6Lumen/watt.. 2A.. 594 Lumen each!

The 1154 you can direct-drive from 14.4.. 883 lumen and 3.38A..

maybe.. a better solution is making your pack 3S2P.. adding two cells but dropping the voltage to 10.8...

you can then use the classic 1185 lamp.. efficiency is 34 L/W at 10.8V! it is pulling 36W at that level.. and you can use the lower-energy-cost 1331 as a swapper at taht voltage dropping the draw to 22W/lamp but efficiency is sky-high of 36.3 L/W.. that means.. simply by swapping to 1331 lamps and using a regulator to hold back voltage spikes.. you can get your output for two lamps up to 1048 Lumen.

========

ok.. that's my 'incan will kick the snot out of led' rant.. now i'll go the LED route since that was your question..

To get nearly the same ouput.. aprox 738 lumen.. you will need at least 7 powerful emitters.. and since it's not terribly difficult to host 4 into a mag-head you cold take two mag heads and use a driver for each group like fatman.. you will get maybe 8000-10000 lux each head... that will only compare to maybe 15000-20000 lux your current lamps provide (as mentioned before .. the LED solution will absolutely be more flood and less throw)..

The other option.. is to use K2 emitters which are higher voltage.. it's possible to use an LDO driver to drop some of the 14.4V down to the 13.2 or so required for maximum output.. you might get 'enough' light from six K2 emitters.

To solve the throw problem.. you can use a bigger head... and mix n match some reflectors.. for example.. putting 3 27mm reflectors into a light.. and 2 of those.. you should get your output up to maybe 10,000 lux per head with only 6 emitters vs 8...

The interesting thing though.. if you run 6xK2 at full power you are only talking about 40W total.. it might be what you are looking for, especially since you can DIM LEDs! you don't loose efficiency like with incan when you dim.. if you dim an incan to 50% power you get 20% light.. if you dim LED to 50% power you get 50% light.

another tip.. use some 'greenish' tint emitters like V1 tint.. you'll thank me later.. http://tv1j.rouse.com talks about that magical outdoor tint.

There are benefits to each.. but with high-power leds at about 25 Lumen/Watt and high-end-high-power incan at 35-40+ lumen/watt.. if you want more light from your battery.. incan will beat LED unless you have low-output.

-awr

sv_ted said:

Thanks for the suggestions. I would prefer LED to HID because of the cost of bulb replacement for the HID. I don't know much about them but saw replacement bulbs at batteryspace that sold for $85!

Click to expand...

HID bulbs have exceptionally long lifespans - thousands of hours is typical. They last so long that you probably won't need to carry spares, nor will field replacement be very convenient. They're incredibly tough compared to the average incandescent lamp since the envelope(s) are made from fused quartz and there's no filament or other fragile internal structure.

I think a 20w halogen puts out about 300-350 lms. 2 makes ~700 lms. As suggested, if you used a 6 pcs of a T or U binned Luxeon LED at say 1A drive configured in 2 head units of 3 pcs, you'd get ~600 lms. With these 600 lms, you'd be able to select 10, 30 or 45 degree angles for different ride/illumination requirements.

sv_ted said:

I am using home made 20w halogen bike lights and would like to replace them with LED's to increase run time. I usually use one 20w, sometimes two at once. My battery is a 14.4 LiIon so I am overvolting the lights. Two lights at once puts out quite a bit of light so I am spoiled. What kind of LED arrangement would get me equivalent light output?

Thanks

Click to expand...

I've used four 3W Luxeon LEDs, driven in pairs, at 7.2V. So with your 14.4V pack, all four could be driven at 14.4V in series. Would pull only 1 amp maximum, at 14.4W. From what I've seen, 14W of LED light is usually equivalent to doulbe the wattage in halogen, so this should be equivalent to at least a 20W halogen bike light. The reflector of choice seems to be the 17mm reflector, because a fair amount of side spill is there, and that is needed for close up viewing. I tried using 30mm optics which gave superb throw, but I could not see close up at my weels. The four 3W settup, which I call the 'QuadStar Bike light', was designed for mtbkndad, for downhill single track racing at night, I think that says enough for the brightness of this settup.




It's easy to modify a D cell Mag head for 4 LEDs. Overheating is not a problem at this power level, from my experience doing this.

Here's a pic of a Mag head with four 3W and four Fraen LP optics:


and with four 20mm reflectors, and a 6C custom made battery tube:



I think you'd be very pleased with the light output of this bike light. I use one on mine and I really like it. My next bike light I'm going to make and put on my bike is going to be a K2-Stunner bike light, using 8 K2 LEDs for up to 1000 lumens

Wayne

Andrew beat me to it. Good overdriven incandescents are more efficient than leds.

But I'll go farther and add something that nobody's mentioned.

Color.

The led is not going to properly illuminate due to a severe lack of red wavelengths in the light beam. That means that brown objects like dirt, leaves, and such will not show up very well.

I've used both led and incan. And I've done more night riding than most anyone I know. The leds don't even compare.

Stay with your incan setup. If you really want to tweak it for maximum performance get a willie hunt regulator. He makes custom regulators specifically for overdriving light exactly like yours.

turbodog said:

Andrew beat me to it. Good overdriven incandescents are more efficient than leds.

But I'll go farther and add something that nobody's mentioned.

Color.

The led is not going to properly illuminate due to a severe lack of red wavelengths in the light beam. That means that brown objects like dirt, leaves, and such will not show up very well.

I've used both led and incan. And I've done more night riding than most anyone I know. The leds don't even compare.

Stay with your incan setup. If you really want to tweak it for maximum performance get a willie hunt regulator. He makes custom regulators specifically for overdriving light exactly like yours.

Click to expand...

I don't agree that the LED will not illuminate as well as incandescents. You have to try a bike light with multiple Luxeon LEDs, and then you'll see. You will not want to go back to the incan.

Wayne

ElektroLumens said:

It's easy to modify a D cell Mag head for 4 LEDs. Overheating is not a problem at this power level, from my experience doing this.

Here's a pic of a Mag head with four 3W and four Fraen LP optics:

and with four 20mm reflectors, and a 6C custom made battery tube:

Wayne

Click to expand...

How do you seal the end of the Mag head were the battery compartment is no longer located?

ElektroLumens said:

I don't agree that the LED will not illuminate as well as incandescents. You have to try a bike light with multiple Luxeon LEDs, and then you'll see. You will not want to go back to the incan.

Wayne

Click to expand...

I second that:thumbsup:.

The colour is a question of personally taste, but about the brightness, there is no doubt about it. Everybody who has seen a multiple Lux-light in real was surprised about the output.

Best regards

____
Tom

I have been using and building LED lights for bike lights for almost 4 years now. This is very important... I ride a recumbent on the STREET so I prefer the LED tint over incandescent so other drivers can see me. I've gone through several designs over the years and have some thoughts.

Helmet Lights
BB500 R2H Minimag Fraen LP/20mm IMS Decent output, drivers easily see me and OK up to 16 MPH on DARK roads. A bit heavy but decent runtime with 2 NiMH AA cells. Downside is it is not truly waterproof.

MillerMods (Fenix) L1P with UWOJ cherry picked LuxeonIII A bit brighter than the BB500 minimag with great spill and very, very small. Runs on a single AA NiMH and pulls 1.73 amps off the battery Waterproof but the runtime is about 75 minutes or so. Has two brightness levels in case the ride goes too long.

Frame Lights
2D Mag driving an R2H Luxeon at 800mA. Amazing throw! That needle-like beam is good for 25 MPH although too narrow for street riding. Runtime was around 8 hours on Powerex 11,000mAH NiMH D cells. (2003/2004)

2D Mag with WX1S LuxeonV driven at 700mA (4.3 watts) with 8AA 1,700mAH NiMH. Very good throw and a larger beam make it very decent to around 18 MPH or so. Runtime is 2 hours and the nFlex 8 output current regulator allows adjustment between output and runtime. :thumbsup: Downside is the beam width could be a touch wider to make it work better...and I would like a few more lumens.

Under Construction Frame Light
HA-III 2D Mag with bored barrel. It will hold four Cree XR-E LEDs with McR 19mm reflectors. Battery pack will be 8AA NiMH 2700mAHI'll send it to AWR to fit onto his BAM! 3 output regulator with drive levels of 550mA (high) 450 lumens, 200mA (medium) 200 lumens and 80mA (low) for 80 lumens. Runtime on high is 3 hours, medium 9 hours and low 26 hours. Chose the Cree XR-E for efficiency and with the McR 19mm reflectors--I should get a bit more floody beam for lighting up the street. Downside is unknown Cree XR-E LEDs, unknown beam shape (might be too floody) and the bezel won't screw all the way down on the tall McR reflectors (loc-tite and F4 tape will seal it)

The Cree should ship in a few weeks so maybe 2 months it will be mounted and I'll see what it can do.

Varroa said:

How do you seal the end of the Mag head were the battery compartment is no longer located?

Click to expand...

I use an oversized o-ring sometimes, and push the cap in. Or I have epoxied it it, but then it does not come out and that can be a problem, unless you make it so you can come in from the front of the light. Using the stock tail cap can work. Sometimes I make a custom tail cap, but most people do not have a lathe to do that.

I've also used aluminum channel for a housing, even just a flat piece of aluminum (not water tight, of course.)

Since I've learned how to make things on a lathe, I just turn my own custom flashlight head. The real problem is a good bracket. I tried making them, but it takes way too much time to do. I've settled upon using the Cateye quick release brackets.

I sent Larry Lagarde a prototype QuadStar bike light. His blog web page is RideTHISbike.com . He is doing a ride, starting today, from Spokane to Ohio or Oklahoma (can't remember which). Says there are lots of tunnels to go through. He is doing a review on this bike light in this ride of his.

Wayne

BentHeadTX said:

I have been using and building LED lights for bike lights for almost 4 years now. This is very important... I ride a recumbent on the STREET so I prefer the LED tint over incandescent so other drivers can see me. I've gone through several designs over the years and have some thoughts.

Helmet Lights
BB500 R2H Minimag Fraen LP/20mm IMS Decent output, drivers easily see me and OK up to 16 MPH on DARK roads. A bit heavy but decent runtime with 2 NiMH AA cells. Downside is it is not truly waterproof.

MillerMods (Fenix) L1P with UWOJ cherry picked LuxeonIII A bit brighter than the BB500 minimag with great spill and very, very small. Runs on a single AA NiMH and pulls 1.73 amps off the battery Waterproof but the runtime is about 75 minutes or so. Has two brightness levels in case the ride goes too long.

Frame Lights
2D Mag driving an R2H Luxeon at 800mA. Amazing throw! That needle-like beam is good for 25 MPH although too narrow for street riding. Runtime was around 8 hours on Powerex 11,000mAH NiMH D cells. (2003/2004)

2D Mag with WX1S LuxeonV driven at 700mA (4.3 watts) with 8AA 1,700mAH NiMH. Very good throw and a larger beam make it very decent to around 18 MPH or so. Runtime is 2 hours and the nFlex 8 output current regulator allows adjustment between output and runtime. :thumbsup: Downside is the beam width could be a touch wider to make it work better...and I would like a few more lumens.

Under Construction Frame Light
HA-III 2D Mag with bored barrel. It will hold four Cree XR-E LEDs with McR 19mm reflectors. Battery pack will be 8AA NiMH 2700mAHI'll send it to AWR to fit onto his BAM! 3 output regulator with drive levels of 550mA (high) 450 lumens, 200mA (medium) 200 lumens and 80mA (low) for 80 lumens. Runtime on high is 3 hours, medium 9 hours and low 26 hours. Chose the Cree XR-E for efficiency and with the McR 19mm reflectors--I should get a bit more floody beam for lighting up the street. Downside is unknown Cree XR-E LEDs, unknown beam shape (might be too floody) and the bezel won't screw all the way down on the tall McR reflectors (loc-tite and F4 tape will seal it)

The Cree should ship in a few weeks so maybe 2 months it will be mounted and I'll see what it can do.

Click to expand...

You must look like a freight train going down the street!

Wayne

Thanks for the info, that explains things. I am experitmenting with Luxeons and bike lights and I am using old Cateye HL500 or HL1500 lights as the bodies and adding luxeons to them myself. They are already bike friendly so that makes it easy. The first one uses 2 x D cells and the second uses 4 x AA cells so you have a choice in power plants.

The points I am trying to make are:

1. leds simply do not emit much in the red spectrum
2. red spectral emission is needed to bring out the reds and browns, this is a KNOWN issue
3. good halogen incandescent bulbs, especially overdriven ones, have a lumens/watt efficacy that is unmatched by leds


At the same time, I do reliaze that:

1. most people are surprised by the brightness of leds
2. color temperature is a personal taste


But, I'm not talking about color temperature. I'm talking about not being able to tell the difference between a brown stick on a brown dirt trail and a brown SNAKE on the same trail.

Now if Benthead is riding on the road that's a completely different story. The strange color of led lights attract attention. This attention makes him more visible and less likely to get squashed.



Believe my guys. I race competitively in 24 hour mtn bike events. There are simply _NO_ led lights used. There are a ton of incans and a growing # of hids. The races would use led lights if they were an advantage. I would use them. But in the dirt/woods they simply can't perform.

And then there's the little problem of lumens/watt like andrew said. Say what you want to, but the numbers don't lie.

Long John said:

I second that:thumbsup:.

The colour is a question of personally taste, but about the brightness, there is no doubt about it. Everybody who has seen a multiple Lux-light in real was surprised about the output.

Best regards

____
Tom

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