battery setup for 9p with LED head

I'm trying to think through this process, but can't seem to come up with any benefit to running additional cells in a 9p light. Obviously, the 9p was designed for more cells to create more voltage to run incan lamps, but with LED technology not needing the voltage, but current flow instead, I am re-thinking my battery setup.

Is there really any benefit to the longer body of the 9p for more cells? Are 2 18500's (or 17500's) really better than a single 18650 and a spacer? Is there really a good use for the extra length battery wise?

I'm currently running an M61SHO in my 9p with standard 123's because the SHO needs the higher voltage (>6vDC). But even the SHO, while a mighty fine light, only puts out 450 lumens. I'm thinking I could get 650-700 with a Nailbender using the CreeXML's, but they don't take near the voltage to run as what the 9p body was designed for. So I could run the same head just as easy in a 6p with the same amount of light for the same length of time using say 1x18650 @ 3100mAH.

Obviously, I understand that the more voltage you have, the less current you need to make the same power - that's basic high school physics, but that doesn't necessarily equate to longer run-times with LED's. Or maybe I have more learning...

So, I guess my question is, can someone help me with figuring out the benefit of the longer 9p body with modern LED's? I guess I'm old fashioned and I'd hate for the extra battery space to be wasted when I could accomplish the same thing with a shorter torch.

arvetus said:

Obviously, I understand that the more voltage you have, the less current you need to make the same power - that's basic high school physics, but that doesn't necessarily equate to longer run-times with LED's. Or maybe I have more learning...

So, I guess my question is, can someone help me with figuring out the benefit of the longer 9p body with modern LED's? I guess I'm old fashioned and I'd hate for the extra battery space to be wasted when I could accomplish the same thing with a shorter torch.

Click to expand...

If the driver can efficiently use the extra voltage, you can do 9v 300 mA in and 3.5v 750 mA out... meaning your cells will be relaxed and giving low current. Also, you could instead do clever things like make an unscrewable spacer to keep things in (rolled up $20, etc).

That's what I'm thinking. The driver has to be designed make use of the extra voltage and draw lower current to produce the same wattage, otherwise it's just wasted energy. If the driver doesn't use the extra voltage, it just gives it off in heat while drawing the same current. I'd be fine with that if I could find a setup that would do that...

I should let an expert answer the driver question, but I believe that buck regulation is more efficient than boost regulation, and thus I think you'll get better run times with higher voltage .And I think the lower current you try to push thru the driver, the less losses you will have, and it will most likely run cooler. Malkoff places a high amount of importance on thermal management.


Regarding the LED, Malkoff also makes a new XML module called the M91A which has 750 lumens OTF. It's on their site. But it also takes higher voltages. I think it requires at least 5.5v.
So, you could keep your 9P length, and have even more output than the Nailbender, by getting the new Malkoff M91A.

Or you could go with your 6P and use the Nailbender with a 18650 if you want the shorter length, and are ok with the 650 lumens.

I almost went with the 91a when it became available, but I wasn't after flood right now. I have (2) 6p's and (2) 9p's. I wanted a good, "general purpose" light and so I upgraded one 6p to the M61 and one 9p to the M61SHO. Same beam, just a bit more umph.

Now for the other 6p and 9p, I had thought of doing something a bit more application specific - perhaps a thrower and a flood, or maybe start playing with some colored drop ins for hunting. I'm not sure yet what exactly I'm going to do, but I got to thinking about the extra voltage capability of the 9p and thought that surely there must be something I can do with that rather than just wasting the space. Either using the extra voltage more efficiently for a brighter light, or finding a longer battery than a 65mm and getting longer runtimes or higher current draw due to higher mA rating... I dunno... If I could just put these batteries in parallel....

In a P60 size head, any of the larger die LEDs such as XML will be floody. They are even somewhat floody with an XPG.
It's because you need a larger relector(and head) to throw with these LEDs.
A very good thrower in the P60 size is the Malkoff M60 with the XRE in it. 150 yards throw, with authority. the XRE is a small die size, and it throws well out of the P60 size reflectors.

Another thing you can do with the 9P is use it for a multi-battery configuration emergency light.
The 9P is just the right length for two AA batteries, so if there was an emergency and you couldn't get your normal batteries, then you could use two AA batteries and it would work. Might not be as bright, but it would give you some light with your Malkoff drop-in such as M60 or M61 on direct drive below the regulation voltage.
Or, if you wanted to keep an M31 on hand, you could get full regulated output from it with a pair of AA batteries. As long as you ONLY use the AA in it, or don't go over 3v input with the M31. It will take a pair of L91 AA though, and not burn up.
So, you would have options with that 9P size of use 3 x CR123, or 2 x AA, or 2 x any of the xx500 size li-ion rechargeables that fit your body bore, with the appropriate module installed.

You can't do that with a 6P.

twl said:

In a P60 size head, any of the larger die LEDs such as XML will be floody. They are even somewhat floody with an XPG.
It's because you need a larger relector(and head) to throw with these LEDs.
A very good thrower in the P60 size is the Malkoff M60 with the XRE in it. 150 yards throw, with authority. the XRE is a small die size, and it throws well out of the P60 size reflectors.

Another thing you can do with the 9P is use it for a multi-battery configuration emergency light.
The 9P is just the right length for two AA batteries, so if there was an emergency and you couldn't get your normal batteries, then you could use two AA batteries and it would work. Might not be as bright, but it would give you some light with your Malkoff drop-in such as M60 or M61 on direct drive below the regulation voltage.
Or, if you wanted to keep an M31 on hand, you could get full regulated output from it with a pair of AA batteries. As long as you ONLY use the AA in it, or don't go over 3v input with the M31. It will take a pair of L91 AA though, and not burn up.
So, you would have options with that 9P size of use 3 x CR123, or 2 x AA, or 2 x any of the xx500 size li-ion rechargeables that fit your body bore, with the appropriate module installed.

You can't do that with a 6P.

Click to expand...

Hearty +1. This is exactly why I put a M61 in my 9P.

That is a decent idea to consider. I do have the M61 already, it's in my 6p. But if worse came to worse, during an emergency and I couldn't get any more CR123's, or couldn't get a recharge on the 18650's or didn't have an extra, I could always swap it to the 9p and go the AA route. That is an interesting thought... I like it.

Are there "battery magazines" available for using CR123a in a bored out 18mm body, or for using AA's in either a standard 16mm or even an 18mm body? Or do most flashlight geeks just wrap the batteries in paper or a couple of dollar bills or something?

I think most people either deal with the rattle, or wrap something (paper) around the batteries.

If you're willing to spend some dough, there's always this:

http://www.oveready.com/sleeves-spacers/123-delrin-battery-sleeves/prod_231.html

http://www.oveready.com/sleeves-spacers/aa-delrin-battery-sleeves/prod_230.html