Surefire CR123 Minimus Headlamp with IMR 16340 appears to work great!!!!!

[bigchelis]

When I had my Surefire LX2 and other Surefire LED based lights I noticed putting rechargeable cells 8.4V input vs. 6V recommended it would always give me the same OTF lumens and the same overall watts which to me indicated it was regulated. With the mindset I went for it and have been using this headlamp now with IMR 16340's and have about 12~15 batteries fully charged and completely depleted them all while working on projects outside my home.

Here is what I found:

• 4.2V input x .527mA at tailcap for 2.17 Watts
• 3.3V input x .560mA at tailcap for 1.84 Watts
• 3.0V input x .625mA at tailcap for 1.87 Watts

The headlamp does not appear to regulate perfectly like it did with my LX2's, but the overall watts stay about the same and still seems to regulate. If it was not regulating with the 4.2V IMR 16340 I would expect 2~4A at tailcap and 5~10 watts of power hence why I convince myself to keep using my headlamp with IMR 16340's.

Here she is:

 

[bigchelis]

Also, the 100 Lumen rating is absolutely perfect when its right in front of your eyes. Most of my lights are 2500~6000 OTF lumens monsters so this is the first time I buy something with such low lumens yet it could not be more perfect. It almost seems odd that such low 100 lumens is so adequate when its right in above your eyes and the light follows my every movement. Headlamps are a must have for us flashaholics.


Side note: the hot spot when wall hunting is horrible yet amazing when I am using the light. The infinite variable and the build construction of the light are absolutely amazing as Surefire products typically are.


best,
bigC

 

[gunga]

So it's okay with imr batteries? Cool. How horrible is the hotspot?

 

[bigchelis]

So it's okay with imr batteries? Cool. How horrible is the hotspot?

Like a Surefire L1 XRE Optic hotspot, but this is pure flood.


bigC

 

[bigchelis]

Forgot to put what a FRESH/NEW primary delivers and its needless to say the same 1.8Watts of power with less mA to keep the overall power the same. I for one will keep using my IMR 16340's on it since it this time it appears the watts are within its intended regulation.

Here is what I found:

• 4.12V input x .527mA at tailcap for 2.17 Watts - IMR 16340 fresh off the charger
• 3.6V input x .505mA at tailcap for 1.81 Watts - NEW 3V Surefire primary
• 3.3V input x .560mA at tailcap for 1.84 Watts - Used 3V Surefire Primary
• 3.0V input x .625mA at tailcap for 1.87 Watts - more used 3V Surefire Primary
• 2.8V input x .608mA at tailcap for 1.75 Watts - " " "" "" 3V Surefire primary
• 2.6V input x 850mA at tailcap for 2.20 Watts - completely depleted 3V Surefire primary.

At 2.6V via 3V Surefire primary the headlamp begins to flicker and then shuts down. So, it seems this headlamp offers great regulation for the duration of the cell and can regulate from 2.6V~4.2V while keeping the watts almost linear.



bigC

 

[P_A_S_1]

Do you get any back scattering of light from your Minimus? Some of them produce a 90 degree light prism from their lens.

 

[Str8stroke]

Very cool. I just assumed it was a no go. Now I have to try this out. Very curious. Thanks for the post.

 

[THE_dAY]

Thanks for the info bigchelis.
I think it has the same variable output driver as the Titan T1A which is also able to take 16340s and keep regulated output.

 

[jso902]

Hmm I thought the rechargeables were for lithium iron po4 batteries only. Might want to make sure you're not over driving it

 

[gunga]

Also, what is the lowest level with this headlamp?

 

[gunga]

Any other updates on this?

I got a minimus vision. The low (after some glass frosting spray) is around 0.05 lumens.

I'm using primaries for now but may try imr in the future.

 

[gunga]

Any more updates? I'm using up some old primaries. Likely at least a 6 month or more supply but wanted to check in on imr usage.

Btw, anyone ever mod one of these?