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Old 01-17-2012, 06:57 PM   #94
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Dear MJS, we think what you are doing with the turntable test is cool and would give a good approximation of the lighting power contained in the main beam of the headlamp. Baja Designs also agrees wholeheartedly that all of us LED light manufacturers should move away from pure marketing hype and move toward more technical measurements. We are completely confident that as consumers are educated on LED technology, Baja Designs lights will come out at the top of the pile. Consumers should be aware of way more factors of LED lights than just lumen output but if we put it all here in one thread, your head will spin. So look for more topics from us in the future.
Your original test was designed to measure the performance of a stage style spot lamp, not a LED based driving lamp; therefore, your test will not accurately reflect the light power contained in the “spill” beam of the headlamp. One of the benefits of LEDs is their inherent “spill” light. “Spill” light would be undesirable and wasted in a stage environment but for an off-road motorcycle light we actually factor this into our optic design and it contributes greatly to the effectiveness of an LED light source. In technical terrain, this spill beam greatly reduces the “tunnel vision” effect you get with many high powered driving lamps. We utilize the spill beam to make the transition between the main beam and peripheral light smooth. It also greatly improves a driver’s ability to recognize terrain and obstacles that would normally be outside the main beam. This is very important especially as you move through your suspension travel during braking, acceleration, cornering, or in rough terrain. The most important benefit of quality optics, which includes this “spill” light, is the considerable reduction in eye fatigue for the rider/driver. Baja Designs is the only off-road light manufacturer that has in-house engineers that designs the optics of our lights. These engineers also happen to be professional level off-road riders and drivers with multiple Baja 1000 class wins to back up the claim. The design goal with the Squadron, Stealth and other Baja Designs LED’s lights is to provide a high intensity center beam for good distance vision along with an appropriate amount of peripheral light. The Squadron driving uses two each of two different reflector styles. There are two “spot” reflectors with a round pattern and two reflectors that add a horizontal component to the main beam.
With the current state of LED technology, comparing them to an HID is not exactly an apples to apples comparison. An HID light is still better for high speed and/or flatter terrain but an LED shines in technical terrain and where you have space and/or weight constraints.
The 3600 Lumens that we claim for the Squadron is based on the total lumens that the LED’s can produce at the drive current that we run them at. It is based on Cree’s numbers for the particular R6 bin that all of our XML LED’s come from. It does not represent the total “out the front” lumens of the lamp (we do this since no other competitor publishes “out the front” lumen numbers for their products). Based on our design work on these reflectors, the Squadron reflectors are approximately 88% efficient. Typical loss for a hard coated polycarbonate front lens is 8-10%. Therefore, calculated through the front lumens should be approximately 2851 lumens.
These numbers do not reflect the output of the LED’s when they get too hot (luminous intensity decreases as the LED’s junction temperature climbs). For this reason, Baja Designs pays great attention not only to the optics, but to the thermal performance of the LED’s and their interface to the heat sink. We are the only consumer LED lighting manufacturer to use solid copper core MCPCB’s to effectively dissipate the heat from the LED into the heat sink. We use active thermal management to reduce LED current when there is not enough air flow to keep the LED’s at the proper operating temperature.
Is your head spinning yet?
Following are candela plots of the spot and wide reflectors that are used in the Squadron. They are normalized to a LED output of 100 lumens. At this time the Squadron lamp is still at an independent testing facility and we don’t have iso plots of its “out the front” performance. We will publish them as soon as we receive the reports.
BD, Thank you for the detailed reply. I wholeheartedly agree with everything said. The two different reflectors mirror what I observed in the beam although at the time I wasn’t aware of the reason.

I’ll use the graphs of the two reflectors to illustrate my original point about published lumen numbers. For the sake of discussion, let’s consider the cd to be throw distance, we’ll call each horizontal line 100’ (I know the graph is not an actual distance measurement). On the wide reflector the spill extends out to 86 degrees. But the spill from 30 degrees to 86 degrees is not necessarily usable light for distance as it would only throw about 25’. OTOH, the main beam is approximately 25 degrees wide and would illuminate over 1100’. However when counting just the lumen output, those lumens contained in the 30 to 86 degree range also get included.

To go a step further, those lumens may be important for a single MC light (to see the side of the road), maybe not so important when the light is being used as an auxiliary light (to say a headlight) and the primary goal is distance. The only way we can tell is if manufacturer's give us usable and understandable information.

Maybe I’m just too skeptical. Or analytical. Or anal (my wife thinks so). Or maybe I need to get a life and just ride more. Anyways, I’m going to move on, mount the light and go

Again, I thank you for publishing this information. Not that I ever had a doubt about the quality and reputation of BD lights. And I think the Squadron is great light in a small package made for a MC. I’m sure there are other LED fixtures out that that are also good; problem is there are probably a bunch of crappy ones too. As a consumer, I always feel better about a company that is willing to back up their marketing with hard facts. It would be great to see BD lead the way with real world data on your products that is easily accessible. Although it may not make a dent in the low end of the market someone needs to take the first step to educate consumers.

PS, the quality of the fixture housing and components is also obvious.
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MJS screwed with this post 01-17-2012 at 07:06 PM
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