Surefire M4

[Monocrom]

Running Surefire incand lamps on rechargeables always is a gamble.

A gamble not worth taking. I prefer a sure thing. Why gamble with SureFire lamps? Lumens Factory makes rechargeable lamps for use in SF lights and specifically with rechargeable cells.

 

[bstrickler]

Personally, I love the M4 body with the M3 head. Nice slender light, with plenty of runtime on stock bulbs if it's a bored M4 body. Too bad I sold mine

 

[Brigadier]

Running Surefire incand lamps on rechargeables always is a gamble.

Really? I've been running 2 M3's on rechargeables for years. One in an MN10/17500 combo, the other a bored body with MN11/IMR18500's. No problems in years of use. The MN11/IMR18500 combo is a real pocket rocket. Great for investigating bumps in the night.

 

[Fusion_m8]

Yes. This is because most of Surefire's incand lamps are designed to be used only with their Surefire CR123A primaries, which will voltage sag more than Li-On rechargeables under the same load. A MN10/11 running on 3xCR123As primaries will see about 6-7v under load. However by using 2xLi-Ons, the MN10/11 will be getting 7-8v under load. This decreased voltage sag increases the brightness of the lamp by burning the filament at a higher temperature, not difficult to imagine what happens to a filament when its burning brighter than it was originally designed for right? The likelihood of the lamp filaments instant-flashing increases in direct proportion to the margins in which the filaments are being overdriven. So if you overdrive a lamp filament by 25%, you'll also being increasing the chances of burning out the filament by 25% and/or decreasing the usable life of the filament by 25% also.

And we haven't even started on the topic of incandescent production tolerances yet, which everyone knows by now varies by a significant margin. For example, take two "identical" P90 lamps and run them on 2xLi-Ons under identical conditions, one lamp can draw 1.5A and the other could draw 1.75A.

 

[Paladin]

Personally, I love the M4 body with the M3 head. Nice slender light, with plenty of runtime on stock bulbs if it's a bored M4 body. Too bad I sold mine

I ran an M3 head on a Leef 2x18650 body for night hikes. Loved the throw, form, and overall utility, but the MN11 lamp did not live long. It didn't just flash, it exploded and glass fragments had to be removed with compressed air.

Paladin