KL4 working voltage?

[wptski]

I've seen this posted, somewhere! What's the working voltage of a SureFire KL-4 head? It's designed for 2x123 but how high can we go?

 

[oldgrandpajack]

Think I remember a post that said you can go up to 6.5 volts, before you are in direct drive.

oldgrandpajack

 

[wptski]

[ QUOTE ]
oldgrandpajack said:
Think I remember a post that said you can go up to 6.5 volts, before you are in direct drive.

oldgrandpajack

[/ QUOTE ]
McGizmo said that it was a boost circuit. I seem to remember that it'll allow a higher than that but I may be wrong!

A "W" bin would allow the use of 2xJSB123.

 

[Steelwolf]

The KL4 is purely a regulated boost circuit. So Vin above the Vf of the LED puts it in to direct drive. This is usually around 7V. Try not to go any higher as nothing will protect the LED from being overdriven.

For the bottom end of the operating range, it will stay in regulation to approximately 3V, but keeps running down to 2.4V. Below that, it may continue to glow.

 

[cliff]

I have a couple of R123s that come off the charger at 3.75 or so volts. They go down to 3.5 volts pretty fast which would be 7 volts for the pair of them. Just wondering if the brief period of overdrive would wreck a KL4. Is heat the main issue, and if so can one be overdriven without damage for brief periods before excessive heat develops?