Surefie U2 battery question

[GLADIUSX1]

Will the Surefire U2 be able to use the rcr123 3.7 volt lith-ion rechargeable's which when fully charge are 4.20 volts each.will they work in the U2 or will it fry the emitter..any and all will help .
Thanx
GLADIUSX1

 

[Rob187]

I'm pretty sure it's not a good idea.

I have tried it (very) briefly with mine to no ill effect but all the levels go weird as the circuitry tries to figure out what it going on.

I have a older U2 which takes 18650 cells which is how I power mine now.

You could try the new LiPOFe4 cells - which have a lower nominal voltage. I'm not sure of this though.

 

[FlashKat]

I would use a 18650 battery if it fits.
If you have a newer style U2 then use a 17670 battery.
You will not get all 6 levels using RCR123 batteries.
I also tried the RCR123 batteries without frying the circuits.