Lumens to candela generator#

See my blog on the legality of bike lights for more detail. There are a lot of lesser LEDs on the market, some perhaps not much better than a halogen bulb. The lamp as a whole is never quite as good as that however, because an LED needs some additional electronic circuitry to drive it, which also takes some power, making the best LED perhaps eight times brighter for the same power input. The current state of the art is 150 lm/w, ten times better than 15 lm/w we got from a halogen bulb. Efficacyįor light to appear neutral, we need to mix some of the less effective blue and red light in with top-value green, so the best that a white light can possibly be… err, well that kind of depends on how truly white you want it! Expert opinions differ, but the LED industry is aiming for 250 lm/w, with 300 or so the likely theoretical limit. green) and lower values for colours either side, tapering off to zero for the infra-red and ultra-violet light we cannot see at all. The SI unit lumen (lm) takes account of that with a kind of points system: awarding a maximum of 683 lumens per watt, for light in the middle of the rainbow (i.e. As an animal active in daylight, we’ve evolved to do best with what the sun produces most of. You could measure light energy also in watts and express the efficiency of a lamp as a simple percentage, but the human eye isn’t equally sensitive to all wavelengths, i.e.

Lumens to candela generator#

It is useful to know if a dynamo lamp is compatible with a generator and slightly interesting to know how much electricity a battery lamp consumes. I said it isn’t useful to know the watts. What matters is how much visible light is produced, and that’s measured in lumens.

If all lights were equally efficient that might be useful to know, but they aren’t, so it isn’t. Watts are how much electrical power the lamp consumes. Safe roads, traffic offences and the law.

What to do if you have a cycling crash?.

Getting sponsorship to cycle for Cycling UK.