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Here is a Technical comparison between commonly available lights http://www.pyrolight...ical-comparison I hope this helps. if you are a distributor or manufacture and you want your lights on that table please send me a sample and I will put it on.
Original post
Hi Everyone. It is this time of year and the sun are getting very lazy. Sleeping in and going to rest earlier everyday. Some of us has build up some hard earned fitness over the last few months and would like to maintain it. One way to do this is to go to gym and breathe in all the Oxygen enriched air and pump some irons. For the rest there is only one option. Stay in the saddle. I prefer the latter.
Undoubtedly most of the latter has considered getting equipment that allows you to do this. But browsing the web has been extremely frustrating. Everyone claims to have the best light on the block. One manufacture claims output in Lumen the other Lux and some uses candelas. Some vendors re-brand lights and use “creative” advertisement or just blatantly exaggerate.
Sadly in South Africa competitors can’t really compare their products. As most don’t want to either because the truth will be too shocking.
As a light fanatic I would like to make it clear that not even price is a good indicator of quality. There are so many options. Here are some key elements to look out for.
1. What type of light technology are they using: HID-Xenon, LED’s or old Halogens?
2. What type of power source: Alkaline, Lead acid, NiMh, or Lithium-ion?
3. Runtimes? How long does it stay on, and does it dim over time?
4. Beam pattern. Do you need lots of light near you or far away? And what about in-between?
5. Is the unit water proof?
6. Mounting mechanism? Clamp or o-ring?
7. Safety and protection features. Does it warn you if the battery is running low? Prevent over heating? Etc...
8. What is the manufacture warranty... 3 months, 1 year, 3 year?
Just to name a few. And the worst of it all is that most vendors can’t really advice you because they don’t really know why that technology is better. I am not going to address all these issue only the first two. But there is a lot to consider and it is extremely easy to buy a cat in a sack. Trust sale person at your own risk.
Each one of these technologies has their benefits so if you choose one other than the ones that I am going to highlight it could be a valid choice for you. Depending on your use.
So let start with number 1. What type of light technology
The answer is LED. Ok that was easy so let’s move on. No sadly I can’t just say that. Why LEDs and not the other. Well basically it is all about weight. LED’s are pushing the envelope when it comes to efficiency. Light energy OUT vs energy IN(Watt). So if you can get the same amount of light out but use half the amount of energy you only need to drag around half the amount of storage. Is that it? No sadly not. LED draw short in one area: Light color. LED is improving but HID Xenon is better at the type of light they generate but there are not so efficient and heats up allot. LED last longer and don’t have a cool down period and also is not affected by vibration like the rest.
But hear me out not all LED are equal. Some vendors are still selling lights that have been around for a few years. So do your research before buying. 5 year ago LED where useless. If you had a 10 Watt LED system you would get 300 lumen out, if you were lucky. This has changed and using the new generation LED will give you about 1000 lumen for 10 watt.
Now you ask why Lumen and why does some manufacture stat other light units? This is a very long topic that has many views. Some will go to war advocating one or the other. It is really tricky because Candelas, Lumen and Lux are all connected and intertwined. There the same thing but measured for different predefined assumptions. I like to simplify it to this:
- Light or visible light is the portion of electromagnetic radiation that is visible to the human eye.
- Lux is this visible light on a very small point
- Lumen is visible light over an area.
- Candelas that is, power emitted by a light source in a particular direction in the visible light spectrum. Typically one SI candle will produce one Candelas...
Lux is a good choice to use if you want to take in consideration the effect of the optics at a specific point, at a specific distance. But then everyone should use the same specifics so that a comparison can be done. And a Laser will produce extremely high lux readings but if you move a mm it will measure nothing. So Lux is not really useful for this application.
Lumen is good for asking how much light an area ahead of me will be illuminated by but it ignores the beam pattern. A beam pattern is important but we will discuss that later. You need to know how bight the area will be to know how bright that area will look like. Lumen is the average Lux over that area.
And well Candelas are really a lot more complex to understand, just go read Wikipedia. But in my option light should be rated in Candelas so that one can compare them.
How much is enough?
Considering that Lumen is the preferred choice of manufactures I will work from there. When I started night riding we had lights that produces about 50- 300 lumen. That was usable and we did single track using normal head lamps. As time went on the lights got better. I find that your eyes will adjust to whatever light there is but it was clear the more light the more speed one can get.
There is something like too much light. Depending on what you do when night riding you need to consider this.
1. Handle bar mounted lights don’t always point where you are looking.
2. Helmet mounted lights add weighted to your head and when misty the beam will blind you
So far I don’t think anyone has reached the light output of the sun so we have some space for improvement. But the sun also is not tied to you or your bike. Last year after converting my handle bar lights to a +2000 lumen monster I ran in to some issue. When on a single track my eyes adjusted to the light and when I came around the corner and my bike was pointing the wrong way it was pitch black. I had no idea where I was going. Then a mist came in to the forest and I could not see a thing. There was a wall of white in front of me. But when I dimmed the light to 700 Lumen I was ok.
If you are considering a handle bar light that exceeds 700 lumen i would suggest getting a helmet mounted one also. Moon light is not going to help you in the switch backs anymore. I would say invest in a light that can pump out +500 lumen. That is just my opinion.
Beam pattern:
But Lumen is not everything. They way the light pumps out and the pattern it makes are extremely imported. The worst type of light has a very narrow beam and/or has sharp rings. This is easy to spot when turning the light on and pointing it to a wall. If there is a dark ring around the light spot it is a no go. A light that has a bright spot that has a gradient transition to a wide area is the best. The smaller the spot the further it will shine but why do you want to see +500m ahead if you can’t see the hole in front of you. Sadly a picture of a beam pattern is not very useful if you have nothing to compare it to.
here you can see two lights. Type A has a very wide beam and it spot is bigger but just as bright. Also note that the light defuses from the spot to the flood area VS the other that has a semi sharp edge.
2. What type of power source?
I say Li-ion is the best option. NiMh are cheap but heavy and you need to run them flat before you charge them. Do you really want to worry about if you are going to make it home because you don’t know how much charge was in when you started? Then don’t get a NiMh. Just remember to not let your Li-ion ran flat. Below 40% is a bad idea. Ideally you want to keep it between 60% and 40% but fully charged is a lot better than fully discharged. If you like more info go and read this article.
How to Prolong Lithium-based Batteries – Battery University
Ok last topic. Beware of bad advertisement.
Here are two products from different manufactures.
The road is 75 meter long
The lights are mounted 1.5 meter away from the wall
Type A
- Claimed Light output: 1000 lumen
- Estimated light output after thermal and optics losses: 763 Lumen
- Battery size 37Wh
- Claimed run time: 3h-3h30
- Actual tested run time is 2h45min-3h05.
- Claims 1200 lumen
- Estimated light output after thermal and optics losses: 460 Lumen
- Battery size 37Wh
- Claimed run time: 6h
- Actual tested run time is: +24h well actually this light never turns off. It runs the battery to destruction. After about 4h the output drops and at 6 hours the light output has dropped to 30% the starting output.
For interest the area being illuminated by Type B is 40% of that of Type A. That is why the two looks just as bright. This is a classic example of Lumen vs Lux. The area of the two light are different and the one that has more light has the greater area therefore the Lux is very much the same for both. Type A illuminates a grater area and produces 65% more light. If Type A had the same optics and the same beam pattern then the area would have been brighter... more lux...
Also note that Type A sells for less than Type B. Interesting is it not?
How did i estimate the light output?
Well if you know what LED is used and you can measure the current and voltage of the LED you can easily use the manufacturer data sheets to determine the output of the LED. I use the voltage in relation to the drive current to get the junction temperature and the current to get the Relative Luminous Flux. Cree provides a tool that one just input the two parameters and wala they estimate it for you.
Summery.
Always do you research!! Compare the light and read reviews. If there is nothing on the internet about a light. Think a moment. why....
I hope that this was useful and that my dyslexia does not steel from the value of this post. Dyslexia does have its benefits but not when it comes to spelling. Happy riding
Attached Images
Edited by Hannes Zietsman, 14 April 2012 - 01:28 .
