So we get you to admit that at least one of those 'miscellaneous costs wasn't included in your price estimate. Given that you started at 50% of the $30 price of a commercial unit, it doesn't take too many of those oversights to prove my point that cost savings are unlikely when diy'ing a tail light.

As to fast tech, I have never ordered from them I have ordered from Futurelec before (another cheap over seas supplier). There were two issues; I always ordered at least 3 of any part I needed since those 'cheap' places had a tendency of shipping faulty parts, though that go better in recent years. And my last order from Futurelec took over 6 weeks for me to receive it.

FYI, I did my first DIY project in the late 60's. It was a home computer capable of performing sophisticated mathematical calculations. I was also from a poor family, so my parents ensured that I understood what the actual cost was for my projects, which was always more than the cost of just the actual parts in the final gadget...

10W was a fairly generous upper limit of the power available from a dyno hub on a bicycle. You (and the site you based your circuits on) clearly were not measuring power under load. Here is a typical power output curve for the SON series dynos (I would be surprised if any other brands were much better)



AS you can see the SON 28 maxes out at around 4W of power when measured under load. In short about 60% less than your estimated available power and even that is more than the LED's in your inefficient circuit are actually receiving. You do realize that by inefficient I am explaining that your circuit is wasting a lot of the available power? In other words your LEDs are receiving a fair bit less than 4W ( I would guess somewhere between 2 and 3W).

Human perception of light levels are notoriously imprecise, so your judgment is likely simply wrong. Compound that with the fact that your taking a commercial products claims that it is producing 600 lumens at face value. As I have said, and that can easily be verified if you desire, those claims are made by marketing people using the same flawed approach you did by relying on light output curves from the device specification sheets.

I have never actually seen a E3 in person. I doubt their and your claims for a couple of reasons. One, the power available from the hub (under load) is not as high as the led spec sheets would state as needed to provide that output. Two, their marketing is depending upon the flawed lumen output claim (which isn't measured) instead of the easier to measure lux ratings which would allow direct comparison with other dyno lights. Three, I have never found any independent measurement of the power output from the E3 when supplied by a dyno...

Yes, and real life comparisons of light level by humans is fatally flawed. (You do realize that your iris adjusts the ammount of light you perceive continuously?) It isn't my ego you would satisfy. I don't care what you claim you are getting, I know you are mistaken. If you actually are diy'ing to learn something the light meter is essential for you to understand what works better and what doesn't. Your perception is never going to do that.

A kit of parts made by someone else is not diy... Further, I suspect that the brighter claim is as false as I have demonstrated your claim is about your diy light.

Yes and that is another factor that REDUCES the light output below the curve you like to make your claims from...

You clearly don't understand those German laws. They place no limit on the power output from the light, physics does that. They specifiy a minimum illumination required (which was achievable by old fashioned halogen light bulbs) and the shape of the light. Any LED light will EXCEED the mimimum light output required by the German laws. The aspect of the laws I like is that it requires that the output from the light be shaped properly to avoid wasting much of the output as your diy and nearly all commercial battery lights do. And as I have explained, the physics is clear, none of your diy lights are brighter than any commercial light that uses the same emitter. Indeed it is likely the commercial product would be brighter since it would likely be using a more efficient electrical design that can deliver more of the dyno power to the actual emitter.

As to throw further, since your light is not producing the output you claim it is not possible that it is producing a further throw (which is dictate by light output) than any other commercial product with the same power input...

You clearly don't understand the basics if you believe you are getting significantly more power at 60 km/h than you do at 25 km/hr. Take a look at the graph above. Under load, the generator output power curve flattens out at just under 4W. You simply aren't getting the output power you believe you are. Measuring open circuit voltages and currents do not produce anything close to actual power output under load you and your source believe they do. And frankly I doubt from your posts that you have even performed those incredibly simple measurements and are instead relying on incorrect information provided by someone who doesn't appear to understand the issues any more than you do; ie, martin (pilom)

If you want the most light you can possibly get, load a couple of pounds (or more) of battery packs on your bike and use a battery set-up. It can supply far more power to the light than any dyno you will ever have on a bike.