aspheric lens with side emitter?

[alnico357]

Apparently this won't work too well..? I have an EverLED in my Mag Light. I put in an aspheric lens with dismal results. Am I correct in thinking I need a Lambertian LED?

 

[Blindasabat]

In short, Yes.
Longer version - you want as much light transmitted forward into the aspheric lens as possible. Cree XR-E are probably the best for this, so if you can find a Cree that fits into the Mag, then that may work best. I think you typically need more than just a PR2 drop-in bulb to use a Cree XR-E.