# What can I expect out of a modified KL4 with 18650s?



## Xcel (Mar 11, 2010)

CPFers,

I’m in need of a modification for the KL4. I have one of the first L4s produced by Surefire and it seems it is just doesn’t cut it anymore. What can be done? I’m planning on running an 18650 and sometimes Surefire primaries. I would like more throw and better runtime (90-120minutes). And if possible two output levels; maybe maximum and ~35-50 lumens.

Thank you.


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## Bullzeyebill (Mar 11, 2010)

Contact one of our modders and see about installing a higher flux Lux V emitter with a low vf. You will not be able to use an 18650, or 18670 in you L4 body, but there are after market 18650 bodies that you can hunt for at the Market Place. I was able to achieve over 100 minutes flat runtime with my KL5 head (Lux V emitter). The KL4 head on your L4 will not like to be run for extended periods of time. You could also sell your L4 and purchase a new L4 with the Seoul P4 LED, and that should give you the runtime you need at decent lumens. Dual output will be a problem unless you can find one of the Sandwich Shoppe E series tailcaps setup with the resistor for low mode.

Bill


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## Xcel (Mar 11, 2010)

I thought the older square sided L4 body was large enough for the 18650?


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## Bullzeyebill (Mar 12, 2010)

Xcel said:


> I thought the older square sided L4 body was large enough for the 18650?



Maybe ok with 17650, not sure about 17670 (protected). Will not fit an 18650, and 18670 (protected).

Bill


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## Xcel (Mar 12, 2010)

Well, shoot. That isn't going to work. 

Would upgrading the L4 even be worth the effect / cost or would it be better to just buy something with new technology?


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