SureFire's got me hooked.

[airtight_python]

I received my 9P today. With only the P90 bulb and 3 RCR123As the output is pretty incredible from such a small package. I lit up the neighbors yard and saw a bunny at about 50 yards. He's probably there often and I've just never seen him. That tickled me, the light will be gun mounted.

I do have a few questions thus far. As I've heard often on this forum, it's probably due to the batteries. Maybe someone can confirm or indicate other issues I should resolve.

The whole tailcap seems a hair loose when it's screwed just far enough for momentary activation. (it gives movement of approximately 3/4 to 1mm). The button is also rather hard to push. The P90 will only light about half the time when pressing the momentary button and the constant position doesn't work, period. The HO-9 Will flicker VERY seldom but will not light.

I do have rechargable protected 17500s and a charger on the way.

 

[eshishlo]

More than likely your problem lies with the batteries. If they are 3 volt lithium ion batteries, they are not made for high amps that the bulb is pulling.
I have a D3, which a 9P with a pocket clip that I run with 17500's from AW, amazing beam and runs strong for 30-40 minutes. I haven't actually timed it, but it is long enough.

If you line up the 2 dimples you should be able to feel the rubber cap move a few millimeters but the actual tail cap doesn't move.

 

[airtight_python]

Thanks eshishlo. The batteries are indeed 3.0v Li-ons. When I say the tailcap moves it's actually the tail-cap. Not just the button... kinda annoying.

 

[kavvika]

"3.0V" Li-Ions aren't the best cells to use...in fact, I don't know of any CPF member that would recommend them. But no worries! Just pick up a pair of AW's 17500 cells and you'll be golden. (Edit: I just saw you mentioned you already had purchase a pair) The bulb will be happier, the batteries will be much less taxed, and runtime will be much longer. You picked a great flashlight! I have a z59 clickie and a lighthound SS tactical bezel on the way for mine, just need rechargeable batteries though!

If you're feeling the need for more lumens, just remember the P91 lamp can't be run on 2x 17500's as the current draw is too high.

 

[airtight_python]

Thanks. If running a P91 on 2 17500s is not recommened and neither are RCR123s, what would you run it on in a stock 9P body? I guess just primaries? Forgive me, all the voltage and draw stuff is still muddy.

Do you believe the tail-cap constant on problem to also be associated with these junk RCR123s?

 

[kavvika]

It's possible, or it might be that mechanically, the spring isn't making full contact. Try backing it off only a few degrees from constant on then try using the switch. If it still flickers badly, try using Deoxit and ProGold on all electrical contacts.

Whether you're running 3x CR123A primaries of 2x 17500's, the voltage is the same and you're going to want a "9V" lamp. Current draw is what you have to watch out for. LiIon rechargeable cells typically can't safely deliver more than 2C of current, which is a current draw twice the actual capacity. So for AW's 1100mah 17500's, that's 2.2 amps. The P90 LA draws ~1.18 amps, so it's well within the safe limit. The P91 LA draws 2.46 amps, and that's too much for a 17500 cell. There is a LA that slots between these two, while delivering far more lumens than the P90 and keeping the same beam pattern, and that's the Lumens Factory EO-9. You should be quite pleased with the performance of that bulb.

Check out mdocod's LiIon compatibility/comparison thread here for much more information.

Now if you still want to run the P91 in the stock 9P body, it would need to be bored out by a machinist to fit 18500 cells, which can safely deliver the current, while providing enough voltage sag to prevent the bulb from blackening. This is risky, since the bore needs to be perfect or the tailcap threads will fall off. OR, you could get Leefs' 2x 18500 body from Lighthound, but that cost's about $60.

 

[mdocod]

Thanks. If running a P91 on 2 17500s is not recommened and neither are RCR123s, what would you run it on in a stock 9P body?

remember Surefire never intended on these being used with any sort of rechargeable configuration, so they designed the P91 and all other HOLA bulbs around the maximum current draw that a CR123 is still worth any beans at (2.5A), and it's a major compromise.

The best solution if you want "upgraded" output on 17500s in the stock configuration is to simply buy a EO-9 from LumensFactory. 2.0A on 2x17500, borderline but works great...

do read the guide linked by kavvika and also found in my sig line to help clear up a lot of confusion.