# NEW DATA****Surefire P91 tested by MrGman @ CPF meet



## bigchelis (Jun 1, 2009)

Finally MrGman got to test the P91.

With 2 IMR 16340's and a non-UCL lens.....It was a Leupold hosts.
380 plus out the front lumens!!!!!!!!





*EDIT:* The Surefire P91 Lamp w/ 2 AW 17670's topped off (4.2v EACH) and my Surefire 6P hosts w/ UCL lens and Solarforce 18650 extention. 


*SureFire P91_____________UCL in SureFire 6P_____2XAW17670,_466.0_____1 sec______,*


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## csshih (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

:O

I'm running one of those!

how old were those 16340s? I suspect mine isn't as bright anymore.


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## bigchelis (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



csshih said:


> :O
> 
> I'm running one of those!
> 
> how old were those 16340s? I suspect mine isn't as bright anymore.


 

The light wasn't mine, thus I don't know how old they were. 

P.S. MrGman took the sphere to the San Jose CPF meet and it would have been cool to see what some of your lights make. Maybe next time!!!:candle:

I think the P91 with 2 IMR 18650's and a UCL lens host will be at and over 400 out the front lumens!!!!!!!!! I had the Lumens Factory D26 500 lumen drop-in. With 2 IMR 16340's it did 270 out the front. While doing outdoor beam shoots the P91 was clearly brighter and others there could see the difference too. I guess Surefire lumens are super underrated with the P91. 

bigchelis


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## bigchelis (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

Does anyone know 100%, if the Surefire P91 will go  with 2 IMR 18650?


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## Outdoors Fanatic (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



bigchelis said:


> Does anyone know 100%, if the Surefire P91 will go  with 2 IMR 18650?


I'd say it is safer and much cheaper to run the IMR-9 than the P91 on those batteries.


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## fivemega (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



bigchelis said:


> Finally MrGman got to test the P91.
> 
> With 2 IMR 16340's and a non-UCL lens.....
> 
> ...



*It would be more helpfull for others if you provide more information about your set up such as battery voltage prior to test, type of switch and host.
AW's soft start switch with 2 protected 18650 works fine with P91 or 1794.*


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## 325addict (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

I only tested a P91 on two 17500 Ultrafire batteries (yes, I know, this is not safe, so I did it only a few seconds) but MAAAAAAN, a WALL of light came out.... much brighter than the (already not bad) P90....

One way to guess if the P91 will go  on two 18650s:

1. Take three brand new, reputable-branded CR123As,
2. take a piece of tubing, 2.5X the length of the 3 batteries,
3. put in batteries, connect the P91, using a separate piece of wire,
4. take one helper, he should measure voltage of the batteries now :thinking:

This test should better be performed pretty quick, otherwise your fingers holding the P91 will burn :green:

If the voltage measured is around 7.4V then it should be safe to use two 18650s. Is the voltage lower, eg 6.8V or so, then DON'T EVEN TRY to use two fully charged 18650s: the P91 will almost certainly instaflash....

It's all about the design-voltage of the lamp: it has been designed to operate on three primary CR123s. The voltage three brand new of them deliver, should be no problem for the P91. Any higher means a severe risk of instaflashing it. 
I personally would judge 0.2V lower than 7.4V the point of danger. So if you read less than 7.2V in this test, I would not try to use 18650s.


Hope this helps.

Timmo.


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## Outdoors Fanatic (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



325addict said:


> I only tested a P91 on two 17500 Ultrafire batteries (yes, I know, this is not safe, so I did it only a few seconds) but MAAAAAAN, a WALL of light came out.... much brighter than the (already not bad) P90....
> 
> One way to guess if the P91 will go  on two 18650s:
> 
> ...


IMR-18650s are not like regular 18650 li-ion batteries at all. Those will definitely kill a P91.


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## bigchelis (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



fivemega said:


> *It would be more helpfull for others if you provide more information about your set up such as battery voltage prior to test, type of switch and host.*
> *AW's soft start switch with 2 protected 18650 works fine with P91 or 1794.*


 

It was a Leopold P60 light. It looks like a 6P. The CPF member had 2 IMR 16340's in it and unfortunately that is all I know. I guess when he didn't want to try it with 2 IMR 18650's he had a good reason..


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## bigchelis (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



Outdoors Fanatic said:


> I'd say it is safer and much cheaper to run the IMR-9 than the P91 on those batteries.


 

The IMR-9 was mine and I do know the set-up.

It was my Surefire 6P with UCL lens and my tailcap has a clickie from DX donor installed. I assume a twistie might have been a better choice. I had topped off 2 IMR 16340's and it did 270 out the front. While the P91 did more than 100 out the front with no UCL lens.:duh2:


Fivemega,
*I will try and get a soft-start and a P91 by this week and try it with 2 IMR 18650's and my Surefire 6P hosts mentioned above. Then I can ask MrGman to see what it will do.*


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## Bullzeyebill (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



bigchelis said:


> Fivemega,
> *I will try and get a soft-start and a P91 by this week and try it with 2 IMR 18650's and my Surefire 6P hosts mentioned above. Then I can ask MrGman to see what it will do.*



Lower your voices guys. No need to shout. :naughty:

Bill


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## 325addict (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

@ outdoors fanatic:

yes, I know, They don't have the slightest difficulties with these high currents. But, even a "regular" 18650 will have no problems with a current of 2.7 Amps..... I think, the difference will become evident with 5 Amps or so.... however, the peak current capabilities of the IMR 18650 will kill the P91 I'm afraid. A regular one will sag in during start-up, an IMR hardly will do so, causing it to instaflash 

What do you think: will it survive using an AW soft-starter??

Timmo.


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## bigchelis (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



325addict said:


> @ outdoors fanatic:
> 
> yes, I know, They don't have the slightest difficulties with these high currents. But, even a "regular" 18650 will have no problems with a current of 2.7 Amps..... I think, the difference will become evident with 5 Amps or so.... however, the peak current capabilities of the IMR 18650 will kill the P91 I'm afraid. A regular one will sag in during start-up, an IMR hardly will do so, causing it to instaflash
> 
> ...


 

Timmo,
Thanks, I should have asked this question before regarding instaflash with AW soft-starter!!

My goal is to get at least 400 out the front lumens with the P91. I think its possible, but only one way to find out.


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## Outdoors Fanatic (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



bigchelis said:


> Timmo,
> Thanks, I should have asked this question before regarding instaflash with AW soft-starter!!
> 
> My goal is to get at least 400 out the front lumens with the P91. I think its possible, but only one way to find out.


That's why I've said: "Why not the IMR-9?"


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## bigchelis (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



Outdoors Fanatic said:


> That's why I've said: "Why not the IMR-9?"


 

Because the IMR9 did 270 lumens with 2 IMR cells and I want to see just for kicks if I can get the P91 to do 400 out the front. I do agree that the IMR9 is more practical because I don't need to worry about instaflash or purchasing a soft-start switch. 

When I get home I will measure the current of my IMR9 D26 drop-in w/those same 2 IMR 16340's to measure the current vs. 2 IMR 18650's. I bet the IMR9 will offer longer runtimes which makes it more practical for my 30 to 45 minute walks after dinner.

Also,
My first Surefire was a 9P with the P91 lamp and primaries. It was what got me into this hobby and I always wondered why it seemed so much brighter than 200 lumens. The 9P is in my avatar w/my 1911.

bigchelis


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## kramer5150 (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

No doubt that thing was BRIGHT. One of the brighter, small lights at the meet.
That Leopold P60 host is REALLY (really) well made. It had a really nice typeIII finish and some solid heft and mass to it. It actually made my M2 feel a little thin and lightweight by comparison.


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## Justin Case (Jun 1, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

Looks like the estimates here are reasonably good:

*MDs Lithium-Ion > Incandescent guide + compatability/comparison chart*
http://candlepowerforums.com/vb/showthread.php?t=161536

Cell configuration: 2xIMR16340
SF P91: 20W, 300 - 125 lumen in 10 minutes

Cell configuration: 2x18500
SF P91: 20W, 320 - 170 lumen in 28 minutes

Cell configuration: 2x17670
SF P91: 20W, 330 - 175 lumen in 31 minutes

Cell configuration: 2x18650
SF P91: 20W, 360 - 215 lumen in 43 minutes

Cell configuration: 2xIMR18650
(P91 and FM1794 should be avoided, will reduce bulb life substantially, very likely to just instaflash the bulb)

Also nice to know that my MN11 driven by 2xIMR16340 is also probably in the 380 lumen range on startup with fresh cells.


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## mdocod (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

Not bad for paper guesstimates if I may humbly say....

I've long suspected the P91 to be brighter than I had estimated but was fearful to "go there" for fear of ridicule so leaned on the side of conservatism on the bulb. I based the original estimates starting with SFs "200" lumen claim and extrapolating up from there based on the expected level of overdrive on li-ion cells... Obviously the 200 lumen claim was under-rated on CR123s 

Check this out though...

First solve for X..

(X/6.6)^0.55=1.085

x/6.6=1.16

~7.656

6.6V would be the estimated Vbulb to achieve the ~2.45-2.50A measured on P91s when driven by CR123s. Work backwards to identify an estimated Vbulb to achieve the ~2.7A that is measured by most folks when running 2xli-ion cells. 

Now, (7.656/6.6)^2.9=1.538

I think it's safe to say that the P91 is truly closer to 260 torch lumen on CR123s working backwards on this. 

SureFire might test their bulbs, but I suspect they are more interested in product placement on paper, but they choose to de-rate rather than inflate numbers to get those nice round numbers and proper product image.... 

MN11 and MN16 should perform basically the same, explains a lot really...

---------------------------

Thank you guys for the real world testing of this bulb. The P91 and 1794 have both recently been through some real testing that, in my opinion, gives them some serious leverage to hold their ground against LEDs for a little while longer


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## Justin Case (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

Ok, I finally figured out what the host light was -- LEUPOLD.

They use a sapphire window for their flashlights. Uncoated, sapphire light transmission is in the 85% range, mainly due to surface reflections. Single-layer coated with magnesium fluoride, light transmission can be 98%. It would be good to know if Leupold coats their sapphire or not. But since they are primarily an optics company, odds might be that they do coat the sapphire with MgF2. Thus, going to a UCL might not produce any gain in lumens. In fact, it might go down since sapphire windows can be made thinner than glass windows for the same strength.


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## gswitter (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

Damn. When we were talking about it, I didn't realize bigchelis had the IMR 18650s with him at the BBQ. I knew he had the tube, and if he didn't already have the soft start switch, we at least had the parts to assemble one, but I thought he was suggesting testing it with 18650 LiCo cells. I'd also be curious to try that particular lamp on three primaries. Oh, well... next time.

My hesitancy to try the P91 on the 18650 LiMn cells is mainly from the posts of others' tests with known bulbs. WA01111s and 1185s are pretty robust with 2x 18650 LiCo cells, and I've had no trouble with them on IMR16340s, even fresh off the Pila IBC charger (usually 4.21V-4.22V). But as I recall from posts by ElectronGuru and a few others, neither the 1111 nor the 1185 can handle the bigger LiMn cells, even with a soft start. Given the optiion, I'd try the P91 on a pair of IMR18500s first.

As far as the set-up that was tested over the weekend. The P91 was purchased new back in December, and had less than ten minutes on it. The IMR16340s were on their third or fourth cycle, and had probably never been run town below 50%. They were fleshly charged by the Pila charger the night before, and both measured 4.21V off the charger.

I'm glad I had another chance to show off the Leupold/P91/IMR16340. The incompatibility with non-Surefire, aftermarket P60 drop-ins is a tough point to get past, but the pre-configured MX-121 package compares quite favorably with similar lights from Surefire when you consider the price, features and quality.


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## bigchelis (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



gswitter said:


> Damn. When we were talking about it, I didn't realize bigchelis had the IMR 18650s with him at the BBQ. I knew he had the tube, and if he didn't already have the soft start switch, we at least had the parts to assemble one, but I thought he was suggesting testing it with 18650 LiCo cells. I'd also be curious to try that particular lamp on three primaries. Oh, well... next time.
> 
> My hesitancy to try the P91 on the 18650 LiMn cells is mainly from the posts of others' tests with known bulbs. WA01111s and 1185s are pretty robust with 2x 18650 LiCo cells, and I've had no trouble with them on IMR16340s, even fresh off the Pila IBC charger (usually 4.21V-4.22V). But as I recall from posts by ElectronGuru and a few others, neither the 1111 nor the 1185 can handle the bigger LiMn cells, even with a soft start. Given the optiion, I'd try the P91 on a pair of IMR18500s first.
> 
> ...


 
The Leupold host is here
http://www.leupold.com/hunting-and-...shlights/mx-121-single-mode-xenon-flashlight/
Very nice hosts and it felt well made too.

gswitter,
Thanks for the imput. It was the missing info to let others know the test conditions.

Jose


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## kramer5150 (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



gswitter said:


> Damn. When we were talking about it, I didn't realize bigchelis had the IMR 18650s with him at the BBQ. I knew he had the tube, and if he didn't already have the soft start switch, we at least had the parts to assemble one, but I thought he was suggesting testing it with 18650 LiCo cells. I'd also be curious to try that particular lamp on three primaries. Oh, well... next time.
> 
> My hesitancy to try the P91 on the 18650 LiMn cells is mainly from the posts of others' tests with known bulbs. WA01111s and 1185s are pretty robust with 2x 18650 LiCo cells, and I've had no trouble with them on IMR16340s, even fresh off the Pila IBC charger (usually 4.21V-4.22V). But as I recall from posts by ElectronGuru and a few others, neither the 1111 nor the 1185 can handle the bigger LiMn cells, even with a soft start. Given the optiion, I'd try the P91 on a pair of IMR18500s first.
> 
> ...




Thanks for bringing your lights to the meet... lots of really nice lights!
Curious... is it the business-end diameter opening of the Leuphold host thats too small to fit the bigger drop ins?... or is it the depth? FWIW, I have been able to mod the DX/LF type reflectors to fit into smaller diameter hosts... and if done right it may actually increase thermal contact with the host body.
http://www.youtube.com/watch?v=TSjTFJldVIQ


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## Owen (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



gswitter said:


> I'm glad I had another chance to show off the Leupold/P91/IMR16340. The incompatibility with non-Surefire, aftermarket P60 drop-ins is a tough point to get past, but the pre-configured MX-121 package compares quite favorably with similar lights from Surefire when you consider the price, features and quality.


What about the Malkoff drop-ins? Those Leupolds look like very nice lights, indeed.
Could those be bored for 18mm cells? From pics I've seen online, the shape at the front of the battery tubes made me wonder.


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## bigchelis (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



Owen said:


> What about the Malkoff drop-ins? Those Leupolds look like very nice lights, indeed.
> Could those be bored for 18mm cells? From pics I've seen online, the shape at the front of the battery tubes made me wonder.


 

I doubt the Malkoff Drop-ins would fit the Leupold. My LU60A adaptor only would only accept Surefire Lamps too. I had to dremel it wider to accept the Malkoff M60 and regular DX P60 drop-ins. Still, the M60 makes 235 lumens and in warm tint those numbers are even less. The Malkoff MC-E warm regulated could be a good choice to compete against the P91. From memory I think the P91 will still out throw a quad emitter in a P60 design, especially Malkoff because he puts the Flood optic on his MC-E's.


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## gswitter (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



kramer5150 said:


> Curious... is it the business-end diameter opening of the Leuphold host thats too small to fit the bigger drop ins?... or is it the depth?http://www.youtube.com/watch?v=TSjTFJldVIQ


It may be just the diameter. The interior is stepped - which creates a very snug fit for the Surefire and Leupold lamps and drop-ins - and the lowest step would need to be opened up a bit. I may give it a whirl with my dremel.

The length may be an issue as well. I'll do some more measuring tonight or tomorrow.

If you're interested, I wrote a few reviews of the Leupold pieces in this thread. I need to go back and add some pictures.


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## gswitter (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



Owen said:


> Could those be bored for 18mm cells? From pics I've seen online, the shape at the front of the battery tubes made me wonder.


Maybe. 17mm AW cells fit easily, even with the labels still on, and the tubes are plenty thick at the ends, but the labeled flats are pretty deep. I need to compare the outer diameter to C2.


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## mdocod (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



gswitter said:


> Maybe. 17mm AW cells fit easily, even with the labels still on, and the tubes are plenty thick at the ends, but the labeled flats are pretty deep. I need to compare the outer diameter to C2.



Often unconsidered is that most "17mm" cells are actually ~16.8mm diameter, while most "18mm" cells are actually more like 18.5mm. 1.7mm of looseness around the 17mm cell would be required to even be close to fitting an 18 

-Eric


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## bigchelis (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

Hi all,

I stopped by a local store after work and purchased the P91 for myself and will be going to MrGmans tommorrow for testing...

So far I checked the current at the tail under load and the voltage w/ no load.

1. The P91 w/ 2 IMR 16340's measuring 4.16v each for a total of 8.32v input = 2.53A at the tail. Total power = 21.04Watts, but less if I could measure the cells voltage under load. In this format with the Leopold hosts it did over 380 out the front. 

*2. The P91 w/2 AW 17500 cells and each cell at 4.22v, but it wouldn't work or light up at all. I then put them back in the 2 IMR 16340 set-up and the P91 works just fine with the same current.:thinking:*

Now I measured the IMR9 or D26 500 Lumen lamp.
1. The IMR 16340's topped off again with 4.16v each for a total of 8.32v. input = 2.34A at the tail. Total Power = 19.46 Watts, but less if I could measure the cells voltage under load. In this format it did 270 out the front lumens with Surefire 6P and UCL lens.

2. With 2 IMR 18650's and each cell measuring 4.16v for a total of 8.32v input. I got 2.40A at the tail for a Total of 19.96 Watts of power...voltage under load will make the power less.


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## gswitter (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



mdocod said:


> Often unconsidered is that most "17mm" cells are actually ~16.8mm diameter, while most "18mm" cells are actually more like 18.5mm. 1.7mm of looseness around the 17mm cell would be required to even be close to fitting an 18


That's what I was sort of alluding to. AW 17mm cells are not a snug fit, but can the Leupold tubes be bored out the additional ~1.5mm for 18mm cells? I don't know. The round portions of the tube are certainly thick enough, but the machined flats are pretty deep. Even if there's enough metal beneath the flats (I'll measure it when I get the tools back out tomorrow), it will probably be similar to boring out a C2/C3/M2/etc, with the potential for bulges in the flat sections.


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## gswitter (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



bigchelis said:


> *2. The P91 w/2 AW 17500 cells and each cell at 4.22v, but it wouldn't work or light up at all. I then put them back in the 2 IMR 16340 set-up and the P91 works just fine with the same current.:thinking:*


Probably the protection circuit. As I recall, AW 17500s are 1100mAh, right? 2.3-2.4A would be exceeding 2C. Did you try double or triple-clicking?


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## bigchelis (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



gswitter said:


> Probably the protection circuit. As I recall, AW 17500s are 1100mAh, right? 2.3-2.4A would be exceeding 2C. Did you try double or triple-clicking?


 
I will try it with 2 AW 17670's then again with the AW 17500's.


EDI: I just tried it again w/ 2 AW17500 cells.
Each cell was at 4.20v for a total of 8.40v imput.
The current was 2.56A with the cell voltage not measured under load. This brings up the total power to 21.5 Watts. This is compared to the IMR 16340 of 21.04 Watts for a total gain of .46 Watts.

The fact that I got slightly more current at the tail; Means more power or just wasted energy? 

Thanks,
Jose


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## Owen (Jun 2, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



gswitter said:


> Even if there's enough metal beneath the flats (I'll measure it when I get the tools back out tomorrow), it will probably be similar to boring out a C2/C3/M2/etc, with the potential for bulges in the flat sections.


I've had a C2, Z3, and a couple of M3 bodies bored with no issues. Don't think I'd be using this one as a handle to open doors, or stuck valve handles like I have the Z3. 
The wall thickness _is_ about cut in half at either the o-ring groove for the tailcap, or round section of the 3 cell bodies though. Can't remember as it's been awhile since I put the calipers to them. 
I wouldn't want to screw it up, and don't have to have it bored, but it would have to fit a Malkoff for me to buy one. 2x18500 in the 3 cell body would be great, though. 
Auction already ended, but there was one of the 2 cell incans on ebay for ~$80 today, while most are more like $130-140.
I need another host like a hole in the head, but I sure do like the looks of them. 



btw, 2 protected AW17500s should run the P91 with a double tap. I'll look for the runtime I posted on the MN11.


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## Owen (Jun 3, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



bigchelis said:


> The fact that I got slightly more current at the tail; Means more power or just wasted energy?


More power, or at least more current, since the voltage probably sagged more for less actual output than the IMR cells.

Here's part of the post I made about 2x17500 on the MN11 a couple of years ago. I was doing 3 minute runs, being more interested in battery life in actual use than a straight run:
_Anyway, I got my M3 before leaving for work today, and gave the 17500s a shot with the MN11 tonight. They did better than I expected. 
I was only doing 3 minute runs, because I frankly didn't expect them to last long, and didn't know if overheating the batteries or whatever would be a concern. Besides, most of my use, especially with a light this bright, tends to be very short, from a momentary flash to maybe a couple of minutes most of the time. 
I use AW's protected 1100mAh 17500s. They needed a double tap/twist to light the MN11. 
The batteries went into protection mode at 26:59, just as I was about to turn the light off from its ninth 3 minute run. On the eighth run there'd been very noticeable dimming, and though the spot was still brighter at the beginning of it than the Wolf Eyes 9V D26 lamp in my Z3, the overall output was quite a bit less._


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## gswitter (Jun 3, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



Owen said:


> Auction already ended, but there was one of the 2 cell incans on ebay for ~$80 today, while most are more like $130-140.


The best price I found was at Botach, and they seem to have storewide 10% and 15% sales pretty regularly as well.


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## bigchelis (Jun 3, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

I just did the current measurement of 2 AW 17670's in my 6P hosts.

With the voltage of each cell at 4.23v for a total of 8.46v input. The current at the tail was 2.63 up from 2 IMR 16340's which were 2.53A.

The total watts now is 22.24 Watts vs. 21.04 Watts. 

I think I will hit the 400 Lumen mark with 2 AW 17670 cells and my UCL lens in my Surefire 6P. 

P.S. I don't have AW 18650 cells to try and after reading this thread in detail it appears even the soft start swith for my 6P will still instaflash my P91 with IMR 18650's. 

Tommorrow we will know for sure if the P91 can put 400 out the front lumens

If I drain my IMR 18650 cells to 3.9 or 4V each will they still instaflash with no softstart??

Thank you all,
Jose


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## mdocod (Jun 3, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



bigchelis said:


> If I drain my IMR 18650 cells to 3.9 or 4V each will they still instaflash with no softstart??
> 
> Thank you all,
> Jose



4.00V per cell should take enough off the top to save the lamp IMO.


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## gswitter (Jun 3, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



gswitter said:


> kramer5150 said:
> 
> 
> > Curious... is it the business-end diameter opening of the Leuphold host thats too small to fit the bigger drop ins?... or is it the depth?
> ...


Upon further inspection, shorter drop-ins should be fine if you open up the lower step. Longer drop-ins - like the Malkoff M60 - may have further issues. There's a shelf at the bottom of the interior of the incan bezel that would need to be removed. Whether the bezel would then be long enough to accommodate an M60 without leaving a gap somewhere is questionable.

I posted a bunch of pics in the main Leupold thread that illustrate the issues pretty well.


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## Owen (Jun 3, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*

Wow. They aren't playing around when they build those things!


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## gswitter (Jun 3, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



gswitter said:


> Owen said:
> 
> 
> > Could those be bored for 18mm cells? From pics I've seen online, the shape at the front of the battery tubes made me wonder.
> ...


At the most narrow point, the diameter of the Leupold bodies are still greater than that of my C2 body (which is bored for 18mm cells), so I believe the Leupold bodies can be bored out as well.


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## bigchelis (Jun 4, 2009)

I expected slightly over 400 lumens, but instead I got more much more.

SureFire P91_____________UCL in SureFire 6P_____2XAW17670,_466.0_____1 sec______,


*466 Lumens on turn on*.!!!!!!!!!!!!:twothumbs:twothumbs

MrGman wants one for himself now. I like to thank him for taking his time to measure and publish the P91 readings on his sticky.


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## Justin Case (Jun 4, 2009)

I'd say that is indirect confirmation that Leupold does not coat their sapphire windows with an AR coating. If we assume 85% transmission for plain sapphire, then we get ~380/0.85 ~450 lumens, which is in good agreement with the measured 466 lumens.

I'm a little confused, however, on what host was actually used. Clearly a "SureFire 6P" can't fit 2x17670 cells.

Also, it would be nice to know the realistic output, not just the first one sec of operation. At ~2.6A draw and an assumed 1.6Ah capacity, the 17670 cells in theory might last for about half an hour. mdocod's FAQ estimated output would decrease to about 175 lumens, which seems like quite good output. But since the max actual output was far higher than mdocod's estimated max, perhaps the min actual output will also be higher. It would be useful to see what the output is at the 1 min, 2 min, 5 min, 10 min, 20 min, and 30 min points. Alternatively, what is the output in the first second of the on-time intervals for an arbitrary 5 sec on, 5 sec off, 5 sec on, etc cycle (or whatever on-off cycle you prefer) that might simulate searching around with a flashlight?


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## gswitter (Jun 4, 2009)

bigchelis said:


> *466 Lumens on turn on.!!!!!!!!!!!!*


Impressive!



Justin Case said:


> I'd say that is indirect confirmation that Leupold does not coat their sapphire windows with an AR coating. If we assume 85% transmission for plain sapphire, then we get ~380/0.85 ~450 lumens, which is in good agreement with the measured 466 lumens.


The design of the Leupold probably isn't helping either. The opening in the bezel is smaller than the reflector, so it's probably giving up a few lumens there. And, the negative spring contacts the base of the head, instead of directly to the body, so there may be a little more resistance. There might be a difference in tail cap resistances as well.

We need to test the Leupold against a 6P with and AR coated lens with the same cells and lamp. Maybe next time there's a get-together, we can arrange to have all the necessary parts and tools. I'd be curious to test the actual current draw with the various cells as well.


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## bigchelis (Jun 4, 2009)

Justin Case said:


> I'd say that is indirect confirmation that Leupold does not coat their sapphire windows with an AR coating. If we assume 85% transmission for plain sapphire, then we get ~380/0.85 ~450 lumens, which is in good agreement with the measured 466 lumens.
> 
> I'm a little confused, however, on what host was actually used. Clearly a "SureFire 6P" can't fit 2x17670 cells.
> 
> Also, it would be nice to know the realistic output, not just the first one sec of operation. At ~2.6A draw and an assumed 1.6Ah capacity, the 17670 cells in theory might last for about half an hour. mdocod's FAQ estimated output would decrease to about 175 lumens, which seems like quite good output. But since the max actual output was far higher than mdocod's estimated max, perhaps the min actual output will also be higher. It would be useful to see what the output is at the 1 min, 2 min, 5 min, 10 min, 20 min, and 30 min points. Alternatively, what is the output in the first second of the on-time intervals for an arbitrary 5 sec on, 5 sec off, 5 sec on, etc cycle (or whatever on-off cycle you prefer) that might simulate searching around with a flashlight?


 
Hi,
I put the hosts info on my first initial thread and the cells were at 4.2v each. 

The hosts was my Surefire 6P w/UCL lens and a Solarforce 18650 extention w/Solarforce clickie. The cells used were 2 AW 17670's.

I will have to wait untill next week for 1min, 2min, 3min, ....readings. I just asked for peak readings, since this is an Incandescent the lumens are dependant on the cells capacity and effectiveness at those high current numbers.

If I had the New AW 18650 2600mAh cells do I need a soft-start swith????

If I repeat this test I want to do it with the new AW 18650 cells.

Thanks,
Jose


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## Jay T (Jun 6, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



bigchelis said:


> Does anyone know 100%, if the Surefire P91 will go  with 2 IMR 18650?



Works for me.

http://www.youtube.com/watch?v=g8qg4LwcxDU


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## bigchelis (Jun 6, 2009)

*Re: Surefire P91 tested by MrGman @ CPF meet*



Jay T said:


> Works for me.
> 
> http://www.youtube.com/watch?v=g8qg4LwcxDU


 
Jay T.

You saved the Day. I want to try it now. 

What was the Current you got at the Tail end?

The current at the tail was 2.63 w/ 2 AW 17670's at 4.20 volts each. With this set up was how I got the 466 lumens.


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## 325addict (Jun 6, 2009)

AW told me, he designed the PCB from the 17500s in such a way, that it will NOT power up the P91 (for safety reasons, it would exceed 2C).

I tried this with two grey Ultrafire(!!) 17500 batteries, and.... they lit the P91 with the first click :thinking: :green:

Timmo.


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## Jay T (Jun 6, 2009)

The tailcap current was 2.73 and falling.

The light is coming out is very white, no doubt that lil P91 is being driven to the edge. So far I have had no failures, however there is no guarantee that the next time I fire it up the bulb will not blow

If you notice my cells were a tick under 4.2 when I ran the test. I have used both my Pila and my Triton hobby charger and the lamp has survived. It is possible that some other chargers might put a little more edge on the cells. If you are nervous let the cells rest and the soft start would be a good idea.

Using my light meter and doing some ceiling bounce tests I get.

17670 - 47 lux
IMR 18650 - 52 lux
IMR + IMR-9 44 lux

If you notice my cells were a tick under 4.2 when I ran the test. I have used both my Pila and my Triton hobby charger and the lamp has survived. It is possible that some other chargers might put a little more edge on the cells. If you are nervous let the cells rest and/or the soft start would be I good idea.


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## polkiuj (Jul 5, 2009)

Just gone thru this thread awhile ago and I'm interested!! 

Looking to get a bored 9P and run a P91 with 2xIMR18500.

Would that be a good idea? 

Can I expect output close to the 2xAW17670? Seeing that the protected cell version of these two is only 100mAH apart.

Also, roughly how much light will I lose to the stock 6P head? Is the 6PD head even worse? Thanks all!!


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## mdocod (Jul 5, 2009)

Hi polkiuj,

An IMR18500 cell has probably half or less the resistance of a protected 17670 cell while having the same voltage potential, which will actually result in the bulb likely being driven HARDER even though the cell capacity is ~30% lower than a 17670. At that point, I think there is a very real risk of having a higher than ideal rate of bulb failures. A Pair of protected 18500s would in some ways be preferable to reduce bulb failures.

Also consider, that it would be less hassle to just pick up a 2x18500 C-C body from FM or Leef or use one of the many possible 2x18500 SF compatible hosts out there. (Rather than have the SF body bored)

The glass lens on most hosts will result in a loss of anywhere from ~1-10% depending on how clean it is, and what coatings or glass type it is. As I understand, the tests in this thread were conducted in a host with a lens but it wouldn't matter either way as the human eye can not see a 10% difference (so even worst case scenario is undetectable)


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## nfetterly (Jul 6, 2009)

Sometime back I saw a posting regarding P91 with 2 IMR16340s. I poked around and sure enough I had a P91 (unfortunately only 1). I usually use a FM x 2 18650 with FM1794 bulb (Nite is setting up buy on those) with a AW 3 level soft start.

The 1794 is bright - brighter than the P91 with 2 x 16340s - but running a 6P that bright (versus a "12P") is pretty impressive. Makes me wish I had a few more P91s (but at ~$30 each I'm not going to buy them - if I get some on MP that will be fine).


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## polkiuj (Jul 7, 2009)

mdocod said:


> Hi polkiuj,
> 
> An IMR18500 cell has probably half or less the resistance of a protected 17670 cell while having the same voltage potential, which will actually result in the bulb likely being driven HARDER even though the cell capacity is ~30% lower than a 17670. At that point, I think there is a very real risk of having a higher than ideal rate of bulb failures. A Pair of protected 18500s would in some ways be preferable to reduce bulb failures.
> 
> ...


Thanks for the reply! But from the video above, even 2xIMR18650 won't blow it. I highly doubt that the 2xIMR16500 will cause it to ka-boom. :devil:

Hmm.. decisions decisions. I considered a solarforce but they don't seem to come in 2xcr123 sizes (no extensions please). Also, 2x18650 is kinda too long =(

1 more question, what would the P91 produce driven by 3xCR123 (as it's supposed to be). More than 470 lumens or less?


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## bigchelis (Jul 7, 2009)

polkiuj said:


> Thanks for the reply! But from the video above, even 2xIMR18650 won't blow it. I highly doubt that the 2xIMR16500 will cause it to ka-boom. :devil:
> 
> Hmm.. decisions decisions. I considered a solarforce but they don't seem to come in 2xcr123 sizes (no extensions please). Also, 2x18650 is kinda too long =(
> 
> 1 more question, what would the P91 produce driven by 3xCR123 (as it's supposed to be). More than 470 lumens or less?


 
I have been running my P91 with 2 IMR 18650's topped off and no problems. It did 476 out the front as tested by MrGman with the 2 IMR 18650 cells. The P91 is just awesome, and I hope it survives 20 hours


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## polkiuj (Jul 7, 2009)

bigchelis said:


> I have been running my P91 with 2 IMR 18650's topped off and no problems. It did 476 out the front as tested by MrGman with the 2 IMR 18650 cells. The P91 is just awesome, and I hope it survives 20 hours


That's exactly what I though I read and saw. Thanks for confirming, bigchelis.

I can't wait to set my hands on one of these babies. =D I'm expecting 400+ out the front at least. lovecpf


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## mdocod (Jul 8, 2009)

polkiuj said:


> Thanks for the reply! But from the video above, even 2xIMR18650 won't blow it. I highly doubt that the 2xIMR16500 will cause it to ka-boom. :devil:
> 
> Hmm.. decisions decisions. I considered a solarforce but they don't seem to come in 2xcr123 sizes (no extensions please). Also, 2x18650 is kinda too long =(
> 
> 1 more question, what would the P91 produce driven by 3xCR123 (as it's supposed to be). More than 470 lumens or less?



[this is actually going to be a response that applies to this post and several others]

SF shoots for ~30 hours bulb life for their tactical lamps when driven by the CR123s they are designed for.

SF HOLA lamps draw ~2.4-2.5A from CR123s. They operate at ~2.2V per cell under this load. (as high as ~2.3V diminishing through the discharge to less than 2V)

A P91 is therefor. roughly a 6.6V bulb (this would be the target "design" voltage). 

Many folks have measured the P91 at ~2.7A from a pair of li-ion cells, and we can study discharge graphs to get an idea of what voltage the cells are running at or work backwards with paper estimates.... Either way we figure, we are over 7.5V pushing the lamp on large fresh from the charger li-ion cells. 

We know that SF "de-rates" their incandescent lamps to more accurately represent an "average" expected output through a discharge. The 200 lumen rating of a P91 is based not on the best possible output from CR123s, nor the worst, but somewhere in the middle, probably right around 6.5V at the bulb give or take a few tenths of a volt to get the "200" torch lumens out the front.

We know from "tailcap" current measurements, that the P91 (and MN11 and MN16) are heavily overdriven on li-ion cells. We know that the bulbs aren't going to last as long this way, there's no getting around this. In fact, on paper, assuming "30 hour" bulb life on CR123s, they shouldn't survive even a second on large li-ion cells so we know that SF has also likely de-rated the "30 hour" life specification as well. 

The 400+ lumen measurements being taken here are based on significant overdrive from fresh off the charger li-ion cells. I don't want there to be any confusion about whether SF "rated" their bulb correctly or whatever. We're driving the **** out of it like this to get that performance. 

So what I'm saying here, in essence, is that, A: on 3 CR123 cells, it will not be a 400 torch lumen bulb, and B: it will not last 20 hours on a pair of large li-ion cells. 

-Eric


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## bigchelis (Jul 8, 2009)

Eric,

Very good info. Can I at least expect 10 hours of life out of my P91 with 2 IMR 18650's???


Well, time will tell. I sure hope so.:thumbsup:


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## mdocod (Jul 9, 2009)

Consider the following:

A P91 draws 2.5A

An MN21 draws 5A split between 2 parallel sets of CR123s, or, again, ~2.5A from each cell in the pack. (in other words, the design voltage of an MN21 would be very similar to a P91/MN11/MN16 to get this same target drain rate from the cells). 

We have had several reported incidence of MN21s blowing on a pair of IMR18650s here on CPF, and that's with the full 5 amp load to drag down the cells.... With only 2.5A load to draw down the same pair of IMR18650s, the P91 should be blowing. 

Reasons why it might not be:

1. Switch resistance (clicky vs twisty)
2. Host resistance (contacts clean?)
3. Rested cells? (LiMn chemistry will settle to ~4.10V after ~24 hours, which will reduce the initial running voltage in operation)
4. Cell temperature? (fresh from the charger, or otherwise warm cells, will be in a state of higher chemical excitement, which will result in higher voltages delivered under a load).


----

So.... You're asking if I think you'll get 10 hours... I think you *should* get 0.1 seconds based on reported events and on-paper estimates  If you get 10 hours I'll be very surprised.

-Eric


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## polkiuj (Dec 8, 2009)

Hello all!! 

Sorry to bring up a really old thread. =(

I finally bit the bullet and got myself a P91. Lumens Factory's Seraph SP-9 and 2xIMR18500 followed soon after. 

These things are crazy!! I thought the Eagletac pushing 250++ OTF lumens was crazy but this is just from another world!! And I'm running the stock lens (probably uncoated).

I'm done modifying it now and just need to clean it up nicely and treat/re-lube it. 

I'm in love. Gotta start scouting for another P91 in case this one goes . 

I hope I got at least 400 lumens outta these babies. All I know is that on ceiling bounce, its worlds apart from the Eagletacs 250 OTF lumens. 

@bigchelis: so how long did the lamp manage to last? Just wanna find out.


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## Outdoors Fanatic (Dec 8, 2009)

polkiuj said:


> Hello all!!
> 
> Sorry to bring up a really old thread. =(
> 
> ...


Gotta love an overdriven SureFire HOLA! Now you need a KT2 + MN21...


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## Kestrel (Dec 8, 2009)

polkiuj said:


> Sorry to bring up a really old thread. =(
> I finally bit the bullet and got myself a P91. Lumens Factory's Seraph SP-9 and 2xIMR18500 [...]


Hey, this is what old threads are for! Sounds like a good setup. :thumbsup:


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## Nite (Dec 9, 2009)

Based on what MDCOD guides have taught me...and my own experience.

Run that P91 off two AW LiCO black label 18500s in a LEEF or 9P body, you will get the same brightness WITHOUT instaflashing the bulb. 380 lumens

also you get 33% more runtime. the bulb will last longer than on IMR.

I dont know why your bulb didnt blow on any IMR cell larger than 16340x2

quoting from MDCODS lion guide



> Cell configuration: 2x18500
> Bulb Options:
> LF D26 ES-9: 7W, 116 - 76 lumen in 94 minutes
> LF D26 SR-9: 10W, 162 - 105 lumen in 65 minutes
> ...


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## bigchelis (Dec 9, 2009)

I ran the P91 tested with 2 IMR C cells at 4.12v each. It worked for about 2 hours, then I tried to go for a walk with my sweetie and no go. I thought it was the lamp, but it was the switch.

I actually still have that P91 and still use it exclusively with IMR 18650 cells. The cells read 4.20v each, but when budget permits I will get the 2600mAh cells for more runtime. 

I estimate at least 10 hours on the P91 lamp and it has only been used with IMR C and IMR 18650 cells :twothumbs


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## Bullzeyebill (Dec 9, 2009)

Bigchilis, the switch burned out? Using a clicky switch?

Bill


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## bigchelis (Dec 9, 2009)

Bullzeyebill said:


> Bigchilis, the switch burned out? Using a clicky switch?
> 
> Bill


 

I am not sure...I couldn't get it to work so I returned the McClicky and the 2nd one worked perfectly. The current is only 3.3A or so and I know the switch can handle that perfectly, so it may have been just one of those that slip throught.

bigC


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## polkiuj (Dec 15, 2009)

Nite said:


> Based on what MDCOD guides have taught me...and my own experience.
> 
> Run that P91 off two AW LiCO black label 18500s in a LEEF or 9P body, you will get the same brightness WITHOUT instaflashing the bulb. 380 lumens
> 
> ...


No blow from even topped off 2 x IMR 18650. I wouldn't expect it to blow with *only* 2 x topped off IMR 18500. Now I've run it and my gosh this thing is insane!! Makes a really good hand and nose warmer too!!

And 380 bulb lumens?? Nah... I think I should be getting 450 out the front lumens, at least. =D

Anyway, I LOVE this setup. Did I mention I love it?? Puts almost all LED's to shame. Haha!

Here are some pics.






SP-9 special edition (only 1 in the world)










The monster in question





Beamshot in brightly lit room (fluorescent light). Taken with macbook camera. AWB. Sorry that it seems white. Lol.




Outdoors Fanatic said:


> Gotta love an overdriven SureFire HOLA! Now you need a KT2 + MN21...


Love? Did I mention I love it? I think I did. Anyway, I love it. =D And that other thing sounds like I'll love it as well xD




bigchelis said:


> I ran the P91 tested with 2 IMR C cells at 4.12v each. It worked for about 2 hours, then I tried to go for a walk with my sweetie and no go. I thought it was the lamp, but it was the switch.
> 
> I actually still have that P91 and still use it exclusively with IMR 18650 cells. The cells read 4.20v each, but when budget permits I will get the 2600mAh cells for more runtime.
> 
> I estimate at least 10 hours on the P91 lamp and it has only been used with IMR C and IMR 18650 cells :twothumbs


10 hours?? That is great!!!! Mwaahahahha!! I'm using a twisty so no worries there!! =D


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