How many volts is needed for a luxeon V?

How many volts is needed to run a luxeon V?

Would it hurt a luxeon V to run it at 9V (say a 6D maglite)?

9 volts would incinerate a Lux V in very short order without regulation or current limits. Lux V needs about 6 volts, but varies according to bin. That's why regulated current sources are so attractive for drivers. In otherwords if you want to use 9 volts with a Lux V, you probably need to invest in a Downboy at something like 917ma from the Shoppe with a suitable heat sink.

The bind with LED's is they have very non-linear response. Incandescents increase resistance as they heat up, LED have very high reistance until they start to conduct, and then have very low resistance once they start to conduct, so small increases in forward voltage can produce huge increases in power dissipation with catastrophic consequences.

For example I have a 1 watt LED.
130ma is Vf=2.775, 36ma, Vf=2.58 inplying a dynamic resistance of about .5 ohms. A 1 watt and lux V have similar characteristics, so driving a Lux V with 9 volts is likely to draw about 6 amps and 54 watts for the few milliseconds before it is incinerated!

Well, depending on the battery chemistry, the votage may sag lower than 9 volt if you are using 3 123s, which we all know is the basis of the Space Needle, but driving a LuxV with 9 volts of NIMH or Li-Ion would most definitely burn it unless it's an extremely high Vf bin

This Streamlight TL-3/LED is a lux V @ 9 volts: http://www.streamlight.com/tl-nf_specs.htm

& has been around for several years already.

3 x 123s in direct drive will bun up a Lux V in short order. Add a 2 ohm resistor and you are very roughly 700ma (near spec), nearly 70% efficiency, relatively flat run time for almost an hour, and really bright.

To beat this performance, add a control board such as sold by taskled.com, leddynamics, or the sandwhich shoppe. Brightness will not increase, but run time will.

This should explain a lot.


-DF