Bicycle as energy generator

[Sunking]

I have several LED bulbs -- Not sure how to best explain this on a forum -- LEDs are direction and therefore, if shined in the right direction, seemingly provide more light than identically rated incandescent or CFL because those bulbs spread light everywhere. It's the opposite case if shined in the wrong direction - that is, LEDs seem to provide less light than their incandescent and CFL counterparts when pointed in the wrong direction.

Well you have discovered on of the dirty little secrets LED manufactures use to spin numbers. LED light is coherent, or as you have witnessed directional like a laser. So here are the two dirty secrets LED manufactures use to make claims.

When they specify Lumens/watt it is at 1 meter in the focal spot of the LED. Move a few degrees in any direction and the light falls off a cliff. Whereas say for incandescent and florescent it an average rating at 1 meter in all directions. However that is not always a bad thing and is useful for task specific lighting like flashlights or reading lamps. But for area lighting it just suks.

Here is the biggest secret. When they perform the test they do so at full rated current, to a refrigerated unit, and only a brief milli-second pulse. Why would they do that? Simple as the led base driver heats up, light output decreases significantly as much as 75% or more. So by keeping it cold and only using pulses, no heat is generated. The other problem is if you operated LED's at their maximum current, they will only last about as long as a china made incandescent bulb.

Lastly what is known by most is LED CRI is not real good, at least not with some of the older designs. It is improving but still a lot of Blue Light Pollution

The technology is improving, and the problems will likely be overcome. But they are not quite ready for mainstream yet except in commercial applications, but homeowners are not likely to be able to afford commercial units.

For now the most efficient for home, industrial, and commercial is T5HO and T8 florescent lighting followed by CFL and LED. Difference between LED and CFL is really a tossup depending on the manufacture. Some better CFL's are quite a bit better then inexpensive LED, and some better LED's are better than inexpensive CFL. But for bang for the buck CFL still wins out unless cold temps are involved.

Now with all that said for outdoors everything changes. Outdoors low and high pressure sodium is king of efficiency, but the CRI is terrible, you know those yeller lights used on highways and street lamps. Police hate them because color cannot be identified.

[Perry]

Now with all that said for outdoors everything changes. Outdoors low and high pressure sodium is king of efficiency, but the CRI is terrible, you know those yeller lights used on highways and street lamps. Police hate them because color cannot be identified.

One of the towns in my area (Woodsville NH) put in Low Pressure Sodium a decade or more ago as street lights. IMO, it make the town look like a warehouse yard or something. When you climb one of the local mountains, you can look around and see the glow of the different towns in the area and the ugly yellow glow allows you to pinpoint Woodsville. Something about all your lumens being on a single spectral line.