Surefire 9P on 4xCR2 cells

I just had a genius idea of the month. To run 4xCR2 cells in a Surefire 9P. Obviously not with the stock incan module but I have an UV module that takes up to 16V, or so they say. So at 12V, I should be well within the limit.

Turns out 4xCR2 are exactly the same length, within 1mm, as 3x123 cells.

I have just one device that runs on CR2 and I use it extremely rarely. It's not a torch. I think the cells will probably go bad before I use them. They are already 10 years old, as I got them in a NIB, but old stock condition.

runtime and mAh capacity appears to be 2/3 of 123s.

Turns out my CR2 cells are more out of date than I thought. 4-5 years. It appears if I don't use them, they will rapidly diminish in capacity, if they haven't already.



But, take your favorite 6P, bored or not, and turns out, 3xCR2 fit if you persuade it hard enough. You have to unscrew the bezel a little. But, it worked. 9V out of 6P. I thought I would have to wrap them in something but the fit was very tight. No rattle. It just worked.



Now I thought I would try 4xCR2 in a 9P. The voltage is 12V but don't worry. I have just the ticket. Enter the 16V UV 365nm module.





4xCR2 are a perfect fit in 9P.





Except there is one problem. It didn't work. Not sure why. Now with the right length, 14mm cells are way to loose inside. I had to wrap them in my favorite device.




And that wasn't enough. Still didn't work. Guess I had to pay more cash to get it to run. It's an expensive hobby. Now I noticed when I use $100, it runs brighter.



Success! 12V out of 9P. And I get to use these worthless cells.

Next project: 5xCR2 out of a 4x123 body.

Another glorious success but it does need a button top magnet for a good fit.

... Just a word of warning ...

You may really be risking a reverse polarity catastrophe by doing this.

Multiple (!) primaries in series, lithium chemistry, old cells, almost inevitably unequal charge levels, low capacity cells, additional physical pressure from the ill fitting tube, etc, etc

And please don't even get me started on tossing a conductive magnet into that mix ...

This is what happened once, with only two poorly matched primaries ....

http://www.candlepowerforums.com/vb...and-account)&p=1447013&viewfull=1#post1447013

It was more of a " can it work" exercise.
Not going to risk it.

I'm always interested in "alternate" possibilities, for the times that they might be all that are available.

Keep those ideas coming!

But I do understand archimedes's warning, and what he says should always be considered before trying these types of "things".

etc said:

It was more of a " can it work" exercise.
Not going to risk it.

Click to expand...

You are an experienced CPF member .... Problem is, not everyone reading these posts may be aware of the risks, unless it is made very clear

The 5xCR2 in a 4x123 body worked very well also. Then I took them out and put back the 2 ancient 2600 AW cells I have.

Then CR2 went into the ancient Seoul P4 UltraFire, back where it came from. My only CR2 lite. I've had it for 6 years and never did figure out what to do with it. It still is pretty bright for the size, even having being superseded by a nice Quark 123. It's the lite that converts either into 2xAA, where it's at normally, or you take out the middle part of the body and it turns into CR2.

So, if the TSHTF, and you got a big bag of CR2 cells that are going to perish anyway, you can always utilize them in either 6P or 9P, provided the modules can take the increased voltage. Same trick as fitting 2xAA into a 9P, or 3xC in a 2D Mag.