Friday, November 23, 2007

"Body" -> Let There Be (Bicycling) Light Part II

Now, I've left you in the dark after my last post on bicycle lighting, so lets brighten it up.

During the last post, we talked a lot about the psychology of bicycle lighting. At the end of the day, you want the brightest light that you can possibly get. This is to not only allow drivers to see you, but also gauge your distance to them.

We'll work through this together by first talking about the various technologies that are on the market today for your lighting needs. In the later part of this post, I'll then give you some specific ideas of what systems you should buy.

There are four primary technologies used for white lighting:

1. Incandescent (with subset Halogen and argon)
2. LED
3. High Intensity
4. Fluorescent

In general, the efficiency is in rank order above. Fluorescent are the most efficient for general lighting and are certainly the best for a home environment, but because of other challenges it does not work well for bicycles.

However, the gap is closing on all the top three. Let's look at some numbers.

In general, you should think about brightness in terms of lumens. If something is brighter, it should have a higher lumens rating. However, this is only part of the battle, to get an idea of efficiency you want to know how many lumens per watt is created.

Now, like most specifications, lumens can be manipulated and don't completely describe the brightness of a light. With all these shortfalls, lumens is still the best measurement.

Since most bicyclist want small light batteries, higher efficiency lights are preferred. What your really want to know is how many lumens per watt of input are created.

In general, here is the following ranges:

Incandescent bulbs: 10-15 lumens per watt
Compact Fluorescents: 40-50 lumens per watt
T8 (Standard Fluorescents): 70 lumens per watt
T12 (1" Fluorescents): 90 lumens per watt

Incandescent bulbs have been around forever, and the best of this technology "halogen," really isn't very efficiency. Not compared to the rest of the technologies, as we can see above.

Now, if you are familiar with those funny yellow colored low pressure sodium lights, they can generate 180 lumens per watt! This is a type of High Intensity Discharge lamp. They are the winners of the lighting wars, but nobody would want to do a bicycle light around them.

The two best technologies for bicycle lighting is a normal HID light or Light Emitting Diode (LED) based light.

A good HID will produce about 50-60 lumens per watt. A little better than a compact fluorescent bulb, but not as good as a T12.

Some of the best LEDs out today will produce about the same amount of light as an HID, or 50-60 lumens per watt.

Now, a HID light is any light that uses high voltage to arc across a gap to make light. As a matter of fact, the low pressure sodium light above is a HID light. LED lights are different from normal lighting. They rely on electricity being generated by electrons cross a semiconductor barrier (called a p-n junction), and part of that electricity being converted into light. The LED light is a miracle of the semiconductor age, and it has only been around in a practical form since 1962.

However, as we write this post today, you can bin the LEDs and get as much as 70 lumens per watt. For example, the Cree 7090 XR-E LED can theoretically be over 70 lumens per watt. I have read that Cree has a roadmap to get to 100 lumens per watt.

The new high technology LEDs are expensive, but they are pretty fool proof. All that you need with these new LEDs is a good heat sink. The HID lights are simply more complicated from an integration standpoint as mentioned before.

A good Cree LED will last around 50,000 hours (less if you over volt it), which is going to be a lot longer than most of use want to be in the saddle. LED lights are extremely rugged as mount the LED so that it stays cool in operation.

So, now that you have some ideas of the technology, I am simply going to tell your what to buy:

1. The Home Brewed Path

If you enjoy experimentation, I would buy the Trailtech SCMR16, and blow people off the trail or street. However, it is very home brewed, as we like to call it in lighting circles, and therefore, you need to do a lot of elbow grease to get it running and keep it running.

So what do you need to do with the home brew system. First you will need to buy the bulb. As of this writing it is around $130-140 USD. However, just having the bulb doesn't solve the problem because you also need to drive it some how.

Probably the best way of doing this is to purchase a battery or a battery pack to drive the bulb. One of the best places to start is on batteryspace.com. Of course, it doesn't stop with just picking up the battery. After the battery, pick up a charger. Then you'll need to figure out how to fuse protect your system. Then you make up a switch. The list goes on.

If it sound a little complicated....it is. Batteryspace sell a whole kit here. However, many people have complained that the mount normally breaks, and you'll need to replace some of the screws from Home Depot. Oh well, this is the normal case with home brewed systems.

Most of the others, will want to basically buy something off the shelf.

2. The Cheap Route

The cheap route still requires some work, and some money. However, a few dollars more on a light scheme is better than being killed.

First buy the Fenix double AA flashlight from the Fenix Store. By using "cpf8" they will take off 8% on the price.

For a little under $60, after discount, this puts out an amazing 175 lumens. Most of us know the old Maglight 6D cell flashlight. This thing blows that flashlight away. I showed my sister one time, and she instantaneously said "where can I get that thing."

Without getting into the details don't run this flashlight from anything but rechargeable NiMH batteries. This this thing chews through batteries (it'll last a little over an hour with a good set of rechargeable batteries), so you want to get a good charger.

Now, I could write a whole posting on battery chargers, but to cut to the short, get the one right here. The LaCrosse charger is extremely cool, plus it comes with enough batteries to get you started. For $40, you'll have a world class battery charger.

How to mount it? We'll Fenix has seen a lot of popularity in there lights for bicycles, and they have just announced a new mount. You can find it here.

However, while this bicycle mount looks great an is recommended by the maker of the flashlight that you'll be using, I have have been using a no-name Chinese flashlight mounter. You can order it here or probably a better and cheaper way is ordering it here.

Although it is completely plastic, it have been working fine for thousands of miles. To make the flashlight grip, I've wrapped my Fenix light with a compressible wrap of rubber, otherwise the holder doesn't grip the flashlight that well.



Finally, for the tail light, the Planet Light Super Flash rear light is the best. Now, this rear light almost has a cult following, but it is a bit hard to find. What is worse is that the name of the light is not very specific.

However, here is the image. You should be able to order it through REI or Bike Nashbar. If you get the charger above, it will come with two AAA batteries that will power the tail light very nicely. The run time for rechargeable batteries in the tail light should be 10 hours on steady mode. The tail light is very eye catching compared to the competitor LED models.

So, for around $140-150, you will get a very workable system. There will be a couple of issues, like a shorter burn time, but the great thing is that you can stop and change your batteries

3. The All In One Expensive Route

If you have around $500, the best thing to buy is a Dinotte combo system. If the tail light in the cheap system is good, then the tail light here is blinding. The lumens in the cheap system is about 175. The lumens here are 600.

If you have enough time to research it, the best spot for this type of activity is either The Candlepower Forums or Lactic Acid Threshold.

The best thing about the Latic Acid Threshold is the great reviews plus a lot of shots of bicycle lights in action. Here are a couple of pictures of the Dinotte in action. The best thing that I like about the Dinotte is that it is an integrated system. You get the headlight and the tail light all in one package with a common battery charger. This makes for simplistic operation.

In the first picture we have the street without a headlight.

Now lit by the Dinotte:



The second one looks a lot better.

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