Electronics, Lighting, & Gadgets - Light selection guide.

[Moderator Note: Since lights are so important in the winter, I'm making this a temporary sticky. Please post your bicycle light comments, suggestions, and questions here. For Home-made bike designs and questions, see Total Geekiness (http://www.bikeforums.net/showthread.php?t=42629).]



Since so many people are starting to get lights for the fall and I was bored, I came up with this.

Edit: Updated 10/2/05 - V4
I realized since most of you commute, charge time is important, I added a column for that too. In most cases, I tried to list the lights with the charge times that come default with the unit. Faster optional chargers may be offered by the manufacturer. Also, I've included this both as an excel and HTML file. With the excel file, you can at least sort by different things. The HTML file is separated by what I think are the most helpful ways of sorting it.

Edit: Updated 10/3/05 - V4a
I added a pivot table to it. If you have office 2001, 2002, or XP, you can use the pivot table, it makes viewing it a bit easier. I also formatted the HTML file for easier viewing.

Edit: Updated 2/7/06 - V5
Changed around my ramblings a little, updated chart.

The numbers are approximate for clean roads, if your roads have a lot of potholes, debris, poor visibility, etc, please take the liberty to knock a few mph off these numbers.

Edit: 10/20/05, 11/9/05, 11/11/05
Added these links for some headlight beam comparisons.
http://eddys.com/site/page.cfm?PageID=493
http://www.lupine.de/en/lighttest/lighttest.html
http://www.mtbr.com/spotlight/lightshootout/
Link courtesy of 2manybikes.
http://pg.photos.yahoo.com/ph/stevea02915@verizon.net/album?.dir=/a1b4&.src=ph&.tok=phqhD2DBX0tUQ3MT
This, I think, is the best one yet:
http://terrengsykkel.no/img.php?d=guide/tester/lykter2005&id=1424
Link courtesy of Ken Wind.
http://www.gearreview.com/2006_led_lights.php

=====================================================

A short primer on different types of lights.

LED's (~20-30 lumens/watt)

LED's are pretty much all solid state. It's basically a computer chip that gives off light. They range from tiny blinkers that run on AA or AAA batteries to full 5+ watt lights running on rechargeable batteries.
The primary use of a blinker is to be seen. Blinkers can operate in constant or flashing modes. The latter mode of operation usually yields the greatest visibility for the cyclist due to the conspicuous nature of the strobe. Another advantage of that mode is the diminutive draw on the batteries. The batteries can usually last days in this mode. Unfortunately, the lights are too weak to be used to see at high speeds in their constant on mode. They are generally good in extremely dark situations when going slowly.
High powered LED lights usually start at 1 watt and go all the way up to 5 watts per LED module. Some lights have multiple modules. Since there's no filament to heat up or break, LED modules can typically be set to either a rapid flashing pattern to attract attention or be run on a solid on mode without risking damage to the bulb.
The color of the LED's are usually white but they can vary from having a slight tint of blue/green to being purplish.
Battery life from most manufacturers range from 2-5 hours for lights running in extremely bright modes to 10+ hours of usable light and 30+ hours of dim light to keep the rider visible.

Advantages:
Virtually indestructable and virtually infinite (50000+ hrs) life.
White light.
Can be powered down significantly to achieve DAYS of run time.

Disadvantages:
Lights are relatively expensive (for now).

Halogen (~10-30 lumens/watt)

Halogen bulbs are basically "space heaters that give off light as a byproduct." (ha ha, laugh!)
They heat up a metal wire to produce a lot of heat and also give off light. Most production lights will either run a MR11 halogen bulb and reflector unit or have a custom reflector and use just a bulb. You can often find a large variety of off the shelf MR11 bulbs to fit your individual needs. The lights can range anywhere from 5 watts to 30+ watts. Some companies have electronic controllers that enable a single light to run a range of wattages from 5 to 15 watts.
The color of the lights can range from a yellowish glow to a bright yellow/white light.
Battery life can range from an hour for lights running in extremely bright modes to over 4 hours in lower power settings.

Advantages:
Lots of different bulbs out there, cheap to replace.
Lights are relatively inexpensive.

Disadvantages:
Relatively short battery life on high brightness.
Filament can break under extreme shock and vibration.

HID's (~50 lumens/watt)

HID lamps basically use a tiny bolt of lightning as the light source. There's no filament, only a spark ionizing a tiny gap between two electrodes. These lights all require a ballast control system that usually comes built into the lamp housing itself. The lights are equivalent to 1.5-3x what a MR11 can put out in terms of light. Since there is no filament to wear out, the lamps usually last many times longer than a halogen lamp if left on. However, the process of starting the spark in the HID bulb wears out the electrode each time and as a result, cuts down on the life of the bulb. Most bulbs are rated for 1000 hours & starts.
Manufacturers usually put their best into these lights and as a result they also get the best battery packs. Run times at full brightness can range anywhere from 3 hours to 12 hours.
The color ranges from white to white with a bluish or purplish tint.

Advantages:
Bright white light.
No filament to break.
Relatively long battery life.

Disadvantages:
Require a 20-30 second warm up before reaching full brightness.
Starting and restarting the lamp cuts down on the life of the bulb.
Require a minute to cool down before turning back on if turned off.
Thin glass bulb still subject to breakage under extreme shock or vibration.
Relatively expensive bulbs.
Relatively expensive lights.

=====================================================

Rearwards Visibility:

Most active rear visibility devices nowadays are the standard battery powered blinkers. They perform adequately in getting the drivers attention from directly behind you but there are also several on the market that give you visibility from the side. These can either be in blinking mode or solid mode. Blinking uses less battery power and also attracts attention better. However, it is more difficult for the driver to pinpoint exactly where you are and where you are going since there isn't anything consistent to reference from. Also, some blinkers blink extremely slowly and a driver may miss you if they are quickly scanning across the road. It's best to run two blinkers, one on solid and one on blink mode.
One of the better ones is the Cateye TL-LD1000. It has 2 rows consisting of a led on each side and 3 LED's facing rearwards. Each row can be independently set on blink or solid.
One of the brightest ones out there is the Niterider tail light. It contains up to 19 LED's in a very small package since it's powered externally. You can either plug it into a splitter powered by a niterider headlamp battery or cut the power cord to rig it up to your own battery. My recommendation is 9+ volts for adequate brightness.
Here's a video of the NR in action courtesy of MechBgon next to the TL-LD1000.
http://www.omnicast.net/~tmcfadden/TL3.wmv
http://www.omnicast.net/~tmcfadden/TL4.wmv
http://www.omnicast.net/~tmcfadden/blinkie_walkaround.wmv

It's a virus! Don't open it!

No, just kidding. Thanks for making this and putting it up.

OK, I'm dumb and don't get it. What do the speeds have to do with lights?

It's an estimate of how far ahead you can see with each light so you can have a general idea of what kind of light to get for the speeds you plan to ride at.

Thanks Slovid, that's actually really usefull. i have nothing further really to say, but my post is so short i'm gonna pad it out a little by adding this little bit of rambling non-sense.

Very cool.

Now if we could have side by side field testing data, we'd be golden. :D

Well I have the cateye el 500 and light and motion dual and I've compared the dual against a 13 watt HID.
So from there, they're just my experiences that I've tried to put onto the table.
Anyway, in case someone's wondering, here's how I got the speeds for use in the inner city.

=ROUND(IF(LIGHTTYPE="Halogen",(-0.0002*WATTAGE^4 + 0.0143*WATTAGE^3 - 0.4048*WATTAGE^2 + 5.5274*WATTAGE - 9.2313)-2,IF(LIGHTTYPE="HID",(-0.0002*WATTAGE^4 + 0.0143*WATTAGE^3 - 0.4048*WATTAGE^2 + 5.5274*WATTAGE - 9.2313)*1.75,(-0.0002*((WATTAGE+4)*1.1)^4+0.0143*((WATTAGE+4)*1.1)^3-0.4048*((WATTAGE+4)*1.1)^2+5.5274*((WATTAGE+4)*1.1)-9.2313))),1)

Then I take that and stick it into the formula below to get max speed usable on a clean road outside the city.
=ROUND((0.0000001*CITYSPEED^5 + 0.000004*CITYSPEED^4 - 0.0009*CITYSPEED^3 + 0.0224*CITYSPEED^2 + 0.0854*CITYSPEED + 0.8849)+CITYSPEED,1)

And the average is =ROUND(CITYSPEED/1.5+ROADSPEED-CITYSPEED,1)

Then during my break at work, I just compiled a list of lights, bulb type, battery life, and wattage.

The 4th and 5th order functions are based on polynomial curve fits of what I felt best worked for me both in the city and outside the city on a dark relatively clean road at certain speeds.

Nice comparison. Thanks.

Now will it tell me if my 2001 NiteRider batteries will make it through one more season? :o

Nice comparison. Thanks.

Now will it tell me if my 2001 NiteRider batteries will make it through one more season? :o

Well if you've been using it daily for half the year... it's like 4 years old x 180 cycles is like 720 cycles already... I'm guessing it'll still work, just not as long. :p

Since so many people are starting to get lights for the fall and I was bored, I came up with this.


I can't open it, what should I try and open it with?

edit post: never mind, it's Excel, I don't have that.

The numbers for the Performance Dual seem b0rked. Speed at 30W is less than at 10W or 20W? What gives? (I ask because that's my light set and the only one I looked at :D)

Thanks for putting that together!

But it looks like there's a bug in the table:

Performance Viewpoint Dual
10 4 15.2 (24.5) 15.9 (25.6 ) 20.5 (33)
20 2 18.5 (29.8) 19.8 (31.9 ) 25.1 (40.4)
30 1 13.9 (22.4) 14.4 (23.2 ) 18.7 (30.1)

=ROUND(IF(LIGHTTYPE="Halogen",(-0.0002*WATTAGE^4 + 0.0143*WATTAGE^3 - 0.4048*WATTAGE^2 + 5.5274*WATTAGE - 9.2313)-2,IF(LIGHTTYPE="HID",(-0.0002*WATTAGE^4 + 0.0143*WATTAGE^3 - 0.4048*WATTAGE^2 + 5.5274*WATTAGE - 9.2313)*1.75,(-0.0002*((WATTAGE+4)*1.1)^4+0.0143*((WATTAGE+4)*1.1)^3-0.4048*((WATTAGE+4)*1.1)^2+5.5274*((WATTAGE+4)*1.1)-9.2313))),1)


That is the best use of Excel ever! Thanks!

I can't open it, what should I try and open it with?

edit post: never mind, it's Excel, I don't have that.

I've converted it to an htm file so you can read it, 2manybikes. I hope that you don't mind, slvoid. If you do, I'll remove the attachment.

The numbers for the Performance Dual seem b0rked. Speed at 30W is less than at 10W or 20W? What gives? (I ask because that's my light set and the only one I looked at :D)

Oops... turns out my equation broke down above like 27 watts.. Fixed! Your performance light set is safe now. :)

I've converted it to an htm file so you can read it, 2manybikes. I hope that you don't mind, slvoid. If you do, I'll remove the attachment.

He's probably released it as Open Source so it's OK. :D

I can't open it, what should I try and open it with?

edit post: never mind, it's Excel, I don't have that.

OpenOffice opens it just fine. I heartily recommend OpenOffice (www.openoffice.org) over that thing Microsoft makes. It's free and it can open all MS Office files.

I've converted it to an htm file so you can read it, 2manybikes. I hope that you don't mind, slvoid. If you do, I'll remove the attachment.


Thanks. It works great.



OpenOffice opens it just fine. I heartily recommend OpenOffice (www.openoffice.org) over that thing Microsoft makes. It's free and it can open all MS Office files.

Thanks. I'll check it out.



Since so many people are starting to get lights for the fall and I was bored, I came up with this

Good job, dude.

But you left me out. I feel so alone ! :( Can I play too?


Lupine Edison 10

Bulb 10/16 W Metal Halide (Xenon), 18° Performance 10/16 W (performance equals 20/65 W Halogen)

Battery Li-Ionen recheargeable bottle battery 12,8 Ah

Burn Time
16 watt (950 lumen, eqv 65 watt) = 6 hours
10 watt (500 lumen, eqv 20 watt) = 9 hours
charge time: 6 hours

Get the new openoffice 2, it's so much better.

Slvoid,

Some hints for next time you work on this:
1. put brand name on same line as each model, have to duplicate many
2. add a MSRP column as so many are price sensitive
3. put speeds in mph and kph in separate columns.

After those changes you can sort to get your needed info.

Some cool sorts:
Find brightest for time
1. sort 1, col f, road speed, decreasing
2. sort 2, col c, run time decreasing

Find best for highest speeds
1. sort col f, max speed, decreasing
2. sort col e, city speed, decreasing

Find best for long rides
1. sort col c, run time, decreasing
2. sort col d, avg speed, decreasing

Get the new openoffice 2, it's so much better.

Slvoid,

Some hints for next time you work on this:
1. put brand name on same line as each model, have to duplicate many
2. add a MSRP column as so many are price sensitive
3. put speeds in mph and kph in separate columns.

After those changes you can sort to get your needed info.

Some cool sorts:
Find brightest for time
1. sort 1, col f, road speed, decreasing
2. sort 2, col c, run time decreasing

Find best for highest speeds
1. sort col f, max speed, decreasing
2. sort col e, city speed, decreasing

Find best for long rides
1. sort col c, run time, decreasing
2. sort col d, avg speed, decreasing

This is really getting good. It can answer so many questions. It should be a sticky, or at least saved for easy posting. I'm almost thinking there should be a Night Riding section in the forums.

OpenOffice opens it just fine. I heartily recommend OpenOffice (www.openoffice.org) over that thing Microsoft makes. It's free and it can open all MS Office files.

Gnumeric (http://www.gnome.org/projects/gnumeric/) does a fantastic job with it as well.

Apples and oranges. Gnumeric is only spreadsheet. OpenOffice is a suite similar to MsOffice and imports/exports well all MsOffice file types.

Biggest changes with 2 are
1. oasis file format, i.e. open file sharing format for greater compatibility. On track to be the html standard for applications. First suite to meet this new standards. More coming next year.
2. spreadsheets are now full length and Excel sheets are now on one sheet instead of split over two sheets.

The OO ver 2 right now is beta, but expect full general release soon.

If you want more details, see the information about the parent Software -- StarOffice 8.
http://www.sun.com/software/star/staroffice/features.jsp

It's only $69 and comes with 60 days of free support.

The ability to export to PDF from the menu is really cool. Here's a SO vs MsOffice quick comparison. 52 million users. Notice how Microsoft is now scrambling to improve MsOffice because of this competition? Did you see how Mass is replacing MsOffice with OpenOffice?
http://www.sun.com/software/star/staroffice/competitive_view.jsp

Other things that would be good to add to sheet comparison is:
1. type of battery used: LA, Ion, Nimh, etc
2. weight
3. mount: bar, head, both

Although it is a nice idea, i doubt that it is very reliable. For instance you claim that a person could safely travel at nearly 23 mph with a Cygo lite Night Rover 12 watt. I have two of the 16 watt systems. I wouldn't even think about traveling 23 mph in the dark with just one. That would be very dangerous as it doesn't light near well enough.

I am currently running both systems at the same time which gives me 32 watts and I am not even sure if i would want to do 23 mph with that. I know that your guide is just a rough guestimate but I don't want people to rely to heavily on it.

Well it also depends on how the light's designed.
Most MR11 bulbs are glass, a lot of light leaks out the side and back. And they're flood bulbs.
Light and motion is, so far, the only manufacturer that designs their own custom aluminium reflectors.
I've been going on night rides with a bikeforums member and on a pitch black road, my 16 watt beam with flood reflector lights up the road enough to give about 3-4 seconds of warning for stuff at around 22-24mph. Like I said, they're just my own personal experiences, of course with glare, poorly designed reflectors (or worse yet, generic reflectors that come with most MR11 bulbs), that's bound to change.

It would be nice if people posted their experiences about how fast they can go with what type of light so we can fine tune this thing.

Does this light comparison
http://www.mtbr.com/spotlight/lightshootout/

which shows the real light given by xyz light help with a sanity check?

I used that light comparison there too. The only problem is that the angles and field of view were really inconsistent.
The thing that surprised me was that the light & motion single 15 watt halogen beam was almost as bright as the 13watt HID. Which means my dual with 26 watts is actually brighter than the HID.

That is surprising. The only way I can think of to validate the results is to:

1. Have people with XYZ light, test it.
1.1 put rock, about 1/2" diameter and stick 1/2" diameter and parallel to direction of travel on road.
1.2 back up til far away from rock and stick
1.3 turn on light and slowly walk bike and mark spot where can clearly see rock & stick
1.4 measure distance between rock/stick and bike

2. convert distance to speeds
2.1 create table X feet traveled per second at Y mph
2.2 adjust table to reduce speed to allow for 4 sec hazard recognition and avoidance time
2.3 look up max safe speed at distance.

Can't test tonight, but this is interesting. I'll try to test tomorrow.

Ok, I realized that my light has a more efficient reflector and apparently, light & motion uses custom halogen bulbs that get 30 lumens/watt. Which means that the 16 watt beam that I normally run gets about 480 lumens, and the 11 watt beam gets 330 lumens, which explains why it gets almost as much light as a HID. And on both beams, I'm running around 800 lumens.
Anyway I updated the chart with slightly more reasonable speeds and added a few things.

Thanks, slvoid, for finally mentioning lumens. Comparing watts does little to tell you how bright the light actually is. Will be updating the spreadsheet to include more lumens numbers? A lot of the info. blurbs about these lights fail to mention that number.

There isn't really a lot of information on lumens out there. L&M quotes the welch and allyn HID bulbs to run 550 lumens on 11 watts and 675 lumens at 13.5 watts. So it's roughly double the efficiency of their custom bulbs and I'm guessing triple that of a normal halogen.

But that's not the only thing, they also designed 2 custom reflectors for my dual light, a flood and spot, the spot really throws the beam far.

So it's really hard to generate an accurate estimate unless we know the type of reflector and the lumens, both kind of hard to get out of certain manufacturers, though L&M is pretty generous about it.

There isn't really a lot of information on lumens out there. L&M quotes the welch and allyn HID bulbs to run 550 lumens on 11 watts and 675 lumens at 13.5 watts. So it's roughly double the efficiency of their custom bulbs and I'm guessing triple that of a normal halogen.

But that's not the only thing, they also designed 2 custom reflectors for my dual light, a flood and spot, the spot really throws the beam far.

So it's really hard to generate an accurate estimate unless we know the type of reflector and the lumens, both kind of hard to get out of certain manufacturers, though L&M is pretty generous about it.



I would add something like "This information is approximate and for comparison only" to the top of the chart.
http://www.mtbreview.com/ shows prices and owners reports on many lights. But you still can't compare the lighting from one light to another very well in some cases. Maybe a link to the light section of mtbreview would be handy for those wanting more about a particular light. If you did add anything I would just add the price, as that's the other thing people always ask about. I think this is going to come in very handy for a lot of riders this fall. Good idea slvoid.

I did not see the update yet as I still can't view it. Does anyone want to convert it for me so I can see it? Thanks.

I did not see the update yet as I still can't view it. Does anyone want to convert it for me so I can see it? Thanks.

I added the price plus the charge time for commuters. It's in both excel and html so hopefully you will be able to view it.

Ok, completed light test. Performance dual 10w & 20 w light set.

Test: dark city street, 2 objects on payment. 1 light stone about
2" by 1 " and a piece of bark about 3"x1"

[ lights on ] __ [ distance to see white ] __ [ distance to see dark ]
10 watt __ 36 feet __ 74 feet
20 watt __ 45 feet __ 114 feet
30 watt __ 69 feet __ 117 feet

Notice that with both lights on, the dark object could not be seen much sooner. One light
is flood and one is spot, so you wider field of vision.

We can do the math tomorrow and calculate safe riding speed. This is approximately
1 1/2 house lots, so I would think safe speed would be roughly in the neighborhood of
13 mph. But we'll see who can make the best math case allowing for a 5 second reaction time
gap.

I use a pair of Cateye EL500 LED headlights up to 20 mph on well lit suburban streets - much faster than the speeds reported on the spreadsheet. Still, I think the spreadsheet is good for relative comparisons between lights. There is one section of completely dark rural road where the EL500s also work fine, but on occasion I can have a little trouble seeing ahead when a car is passing by.

Planet Bike's Superspot is another LED light that uses 4 AA batteries, a feature I like. According to the spreadsheet, it is good for higher speeds than the EL500. Has anyone done a direct hands on comparison between the Superspot and the EL500?

Yikes, ur right, sorry, the EL500 is not supposed to be that low. Fixed.

Looks like the attachment hasn't refreshed yet.

Anyone know how the Nitehawk Emitter compares to the Cateye EL500 and the Planet Bike Superspot?

Very nice work, Slvoid! Thank you!

Notice that with both lights on, the dark object could not be seen much sooner. One light
is flood and one is spot, so you wider field of vision.

We can do the math tomorrow and calculate safe riding speed. This is approximately
1 1/2 house lots, so I would think safe speed would be roughly in the neighborhood of
13 mph. But we'll see who can make the best math case allowing for a 5 second reaction time
gap.

Wow 5 seconds seems like a long reaction time. I usually consider 2 seconds reaction time. Is this what is recommended?

Ok, completed light test. Performance dual 10w & 20 w light set.

Test: dark city street, 2 objects on payment. 1 light stone about
2" by 1 " and a piece of bark about 3"x1"

[ lights on ] __ [ distance to see white ] __ [ distance to see dark ]
10 watt __ 36 feet __ 74 feet
20 watt __ 45 feet __ 114 feet
30 watt __ 69 feet __ 117 feet

Notice that with both lights on, the dark object could not be seen much sooner. One light
is flood and one is spot, so you wider field of vision.

We can do the math tomorrow and calculate safe riding speed. This is approximately
1 1/2 house lots, so I would think safe speed would be roughly in the neighborhood of
13 mph. But we'll see who can make the best math case allowing for a 5 second reaction time
gap.

Something's odd about that, by your calculations, that means a HID light is only good safely up to 13mph?

Viewpoint Dual halogen, NOT HID. L&M HID is still on wish list.

http://www.performancebike.com/shop/profile.cfm?SKU=17410&subcategory_ID=4320

The 13 mph is very very rough guessimite, I'll have actual mph at 3 sec gap and 5 sec gap for light and dark later today.

A standard halogen should get around 20 lumens/watt.
L&M's HID gets about 675 lumens at 13.5 watts.
That means that your 30 watt halogen light's making 600 lumens. If you can only safely travel at 13mph on 600 lumens, 675 isn't going to get you any more.

Anyway, to find the distance to reaction time and speed, distance=mph*1.46*reaction time.

So for a 2.5 sec reaction time, you need to be able to shine a light about 65ft.

A standard halogen should get around 20 lumens/watt.
L&M's HID gets about 675 lumens at 13.5 watts.
That means that your 30 watt halogen light's making 600 lumens. If you can only safely travel at 13mph on 600 lumens, 675 isn't going to get you any more.

Anyway, to find the distance to reaction time and speed, distance=mph*1.46*reaction time.

So for a 2.5 sec reaction time, you need to be able to shine a light about 65ft.


Much improved spreadsheet. I don't understand the differences between:

1. avg city speed
2. max speed
3. road max speed

Why would road be higher than city with the same light?

I had my objects reversed and overstated the range, here is the corrected numbers

light______dark___light
10 watts____40______70
20 watts____58______95
30 watts____58_____115

Formula for feet/sec at 2.5 sec reaction time:
1. convert to feet/second: /2.5
2. convert to feet/hour: *60*60
3.convert to mph: /5280
thus
@round(((Distance/2.5)*60*60)/5280,1)

Results for safe speed
Light______dark ojects____light objects
10 watts_________10.9_____________19.1
20 watts_________15.7_____________25.9
30 watts_________15.7_____________31.4

Slvoid's formula for same light
Light___________city______________road
10 watts_________15________________20
20 watts_________20________________27
30 watts_________23________________31

Conclusion: Slvoid's value are accurate for light objects. However for dark objects, like rain covered or for dual light systems where one light may be a flood and the other a spot, the speeds are too high.

For new riders, remember the max road speed is for dry conditions and to avoid overriding lights you'll have to adjust for: fog--rain--mist--wet surfaces--snow--leaf obstruction.

Thanks for confirming it. I guess my speeds are slightly higher cause my l&m halogen bulb gets 30 lumens/watt vs. 20 lumens for standard halogens plus the custom reflector really throws the beam far. I'll adjust the curve that calculates the speeds and adjust it down a little.

The reason why the speeds are slower for the city is because there's a lot of ambient light in the city. So your eyes aren't dilated as much. The result is that they're not as sensitive to light and you don't see as far, plus dim street lighting usually casts an even masking orange glow over everything that your lights have to power through. It's easier to see the road with less wattage without a lot of lights distracting you.

Another thing to keep in mind is the glare on the road from oncoming cars, the moment a car rounds a corner in the opposite direction, your visibility of the road can drastically be reduced from 150ft down to less than 20.

You're welcome.

It was annoying the way the perf. bulbs worked. I wanted to twist the lens of the brighter light and bring the light into a sharper spot light.

How about another RFE, add to second sheet the notes:

1. why speeds are lower
2. rough lumens/watt for different light technologies, i.e. 20/watt for halogen, 50/watt for L&M HID
3. ref to geek light
4. any other references that would be good to know

I'm working on a sample of how to use during twilights and plan to post later today.

I added the price plus the charge time for commuters. It's in both excel and html so hopefully you will be able to view it.

Thanks for the html version. I can see you added some useful information. Excellent!

I already learned that my favorite light went down $100 and it now has a more powerful battery for more run time. If one starts with some knowledge of available models and prices you can even see some light manufacturers responding to market demand. If you decided to make an annual fall update, that would be nice too.

Sometimes having way too much free time is a good thing ! ;)

How to use Light Selection Guide

Suggestions on how to select a headlight for your commuting situation:

1. Verify latest sunrise/sunset date for your location.
North America: Dec 14, 2004 Sunrise 7:13am, Sunset 4:35pm

2. Figure out how much time you need if no flats/delays
30 minute commute: 7:30-8:00am, 5:00-5:30 pm
AM, 0 minutes; PM 30 minutes; Day: 30 minutes

60 minute commute: 7:00-8:00am, 5:00-6:00 pm
AM, 13 minutes; PM 60 minutes; Day: 73 minutes

3. Add 30 minutes for worst case, flat, equipment failure and weather delay
30 minute commute -- 60 minutes burn time
60 minute commute -- 103 minutes [ 1 hr, 23 min] burn time

Sort the light selection guide for your perfect light

4. Sample Sort -- Sort light chart: fastest speed, city lights
Sort #1, K, City Max Speed, decreasing
Sort #2, G, Run time, decreasing
Sort #3, C, Price, ascending

5. Sample Sort -- Sort light chart: cheapest, fastest
Sort #1, C, Price, ascending
Sort #2, K, City Max Speed, decreasing

Here is the skinny on twilight, unfortunately too many try to ride/drive during Civil or Nautical twilight without lights on and only turn on the lights at astronomological twilight. Simple summary:

4 Standard levels of darkness transitions:
Actual sunrise/sunset -- still can work without lights
Civil twilight -- see objects and some details
nautical twilight -- see object outlines
astronomical twilight -- night

Here's the official word:
http://aa.usno.navy.mil/faq/docs/RST_defs.html



Civil twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 6 degrees below the horizon. This is the limit at which twilight illumination is sufficient, under good weather conditions, for terrestrial objects to be clearly distinguished; at the beginning of morning civil twilight, or end of evening civil twilight, the horizon is clearly defined and the brightest stars are visible under good atmospheric conditions in the absence of moonlight or other illumination. In the morning before the beginning of civil twilight and in the evening after the end of civil twilight, artificial illumination is normally required to carry on ordinary outdoor activities. Complete darkness, however, ends sometime prior to the beginning of morning civil twilight and begins sometime after the end of evening civil twilight.

Nautical twilight is defined to begin in the morning, and to end in the evening, when the center of the sun is geometrically 12 degrees below the horizon. At the beginning or end of nautical twilight, under good atmospheric conditions and in the absence of other illumination, general outlines of ground objects may be distinguishable, but detailed outdoor operations are not possible, and the horizon is indistinct.

Astronomical twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 18 degrees below the horizon. Before the beginning of astronomical twilight in the morning and after the end of astronomical twilight in the evening the Sun does not contribute to sky illumination; for a considerable interval after the beginning of morning twilight and before the end of evening twilight, sky illumination is so faint that it is practically imperceptible.


So on darkest day for US, 12.14.2005 the times are

sunrise/sunset--------- 7:13 am, 4:35 pm
civil twilight----------- 6:42 am, 5:05 pm
nautical twilight ------- 6:08 am, 5:39 pm
astronomical twilight --- 5:36 am, 6:02 pm

This is an updated sheet where sorts work properly. Temporary post pending response from slvoid.

Thanks, I'll take a look at the thing when I get home. This started out as a way to pass time at work hehe..

Anyway, the actual version with the full formulas and 4th and 5th order approximations is like 5 megs, what I did was copy the information into another sheet and paste it as just the information w/o the formulas, that's the only way I got the information down small enough.

Ok, in my zip are both Excel and OpenOffice formatted sheets. Original with strings did not sort properly because it used alphabetical sorts instead of numeric sort.

*** ERRATUM ***

Cateye Stadium is no longer available.

So it looks like Lupine, Light & Motion and Niterider are the only ones who make a bright light with 4 hours or more of burn time.