Future tests include direct driven XP-L V6, XM-L2 U4 and unknown BIN from 1405, and XP-G2 S3 and S4. All will be tested domed and dedomed. I already have all the LED’s. Just need to build a few drivers and dedome a few LED’s. I also plan to dedome a red and green XP-E2 for testing.
I wouldn’t mind if coyotes went extinct.
i received one 1504, very good flashlight, buyed another 2 complete: one 1405 & one 1504
Nice, most of this is what i want to try out, the XP-L V6, XM-L2 U4 & XP-G2 S3 and S4, good to know what different combinations result in performance, because i don’t have any measuring equipment.
I am also very curious about this dedoming red & green led’s and if it really don’t improves kcd, djozz says it don’t & he is often on point with this stuff, but i feel without the gel dome lens it really should be a smaller & more intense surface & result in an improved light source for throw, but maybe i am missing some fundamental knowledge about how the lack off phosphor changes these things.
One thing i hope someone here can answer is, can i run a XP-G2 DD? Direct drive as in without a driver just single mode.
I know XP-L’s & XM-L2’s can take anything a single battery can throw at them, as long as they are sitting on a DTP mcpcb & are heatsinked well enough to keep heat in check.
But how does the XP-G2 react? The XP-L just keeps getting brighter & brighter the lower the resistance i can get in the circuit for them, but i have no idea really on what to expect from the XP-G2, will it suck 6-7Amps like the XP-L and get to its maximum DD brightness on its own, or is it better to limit the resistance by introducing some resistance in the circuit, so the XP-G2 doesn’t get so close to its maximum wattage and start losing output.
And will the XP-G2 start to get blue like the XP-E/2’s if i over drive them to hard, or will the just lose output.
Any insight to this would be appreciated 
Post 51 should answer your question.
Thanks MRsDNF, yes i am very familiar with djozz charts, thanks djozz 
But I am sorry i am not sure that it does that, driving a led from a single high drain battery in as low resistance circuit as i can make it in a flashlight & running a bare led on a mcpcb (and in this case a reflector) in steady state from low to very high, is a bit different.
We can use djozz data for educated guesses where we end up at various amps & how much before it burns out for example .
But i can’t extrapolate how the XP-G2 S3/S4 will react running DD straight from the battery at as much amp the battery can provide, at the instant i turn the switch when the led is also cold.
For example an XM-L2 or an XP-L can output more from cold, the first few seconds at various amps and rapidly dropping of course than djozz charts would show.
I wonder how high can the XP-G2 go when running from only the battery, and is it preferable to lower the max by introducing a little resistance to keep the output in optimal range, or maybe the high Vf is so limiting anyway so less resistance always lead to more output if properly heatsinked like the XP-L.
Most of the times i read about people using XP-G2’s (in modded throwers) it is with regulated drivers at around 5A or lower, because you get very little extra output after that.
But i guess now that i think about it some more, modders like Vinh i think sells lights with XP-G2’s running single mode with no drivers, so it is probably OK to run them fully DD & not worry about it.
I will see soon anyway because that is what plan to do
I don’t recommend running DD with no driver. Just use a DD driver that’s single mode. The problem is the you won’t use a protected cell for maximum output. At least the firmware has some protection built into it. What if the flashlight is accidentally left on. There would be no driver or battery protection. I think the parasitic loss from a driver would be minimum compared to the extra safety the driver would have.
I agree for most it is an bad idea, but i am the inbuilt protection when the light start to dim, and that is very soon when running straight DD i turn it off & pop in a fresh battery, very very seldom do i find i have drained a battery for lower than 3.5-3.7v, the output loss is just to much when a few seconds of switching a battery can bring it up again
I really can’t see any reason why i would want anything other than single mode & a driver blocking the current in a thrower light like this.
But i use these mostly for fun, i don’t use them for anything functional like a gun light for example.
But n10sivern, please when you plan to do all this testing of various led setups on this, and you say you don’t believe there to be very much parasitic losses from a driver, please test one of them with a FET driver & one straight without so we will know.
You may be right & if you are i may change my mind, but i think we lose a not insignificant % of max output with a driver.
But i totally agree that it is best to use a driver with some protection, i would newer build a DD light like this to anyone else than me, if you don’t check your battery’s with a DMM constantly after use it is very easy to damage them.
I’m sure there is a loss with a driver, I am just willing to bet it is not significant. I will try to test and see. I have some VTC5’s that need a good test!
My data can provide more than educated guesses, they provide usable data on the led. In other words, it is quite usable to calculate what happens inside a flashlight. Just the lumen calibration is debatable. The educated guess part is what else happens in your flashlight: the light loss inside a flashlight from reflector, lens and temperature sag, the resistances on various places, some variation in led binning.
If you use my emitter switch and spring data combined with HKJ's battery data you know close to what will be the current. In this case: say that you aim for 5A for an old batch XP-G2 (which is very close to maximum output) you can see in my most recent XP-G2 test that the led voltage is 3.7V.
With bypassed springs, wire losses and switch losses taken into account (if done well, it might be no more than 0.15V), the battery must provide 3.85V. Use a high drain cell, like the Keeppower 4200mAh, and at 5A it gives off 4.0V initially, 3.8V after 10 minutes. The actual current in your flashlight will thus be higher than 5A, but at 6A the led voltage is already 4.05V, so there's no cell that will kill it.
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If anything is less than ideal, like a lower drain cell, a higher voltage led from a newer Cree batch, or thinner led wires, or a non-copper braided spring (at 5A: steel->0.25V, copper alloy->0.08V) you will not probably be below 5A.
Which IR led do you suggest for this host?
Really thanks djozz that is what wanted to know, that in single battery applications, the XP-G2 is safe to run DD from the battery, and if i follow you correctly it would seem that it is.
And i am sorry for saying “We can use djozz data for educated guesses” when the correct statement was “I can only use…….” 
This is all very interesting and i am glad i raised the subject because, the estimates you gave on various losses with a volts that i can use to subtract from your & HKJ’s charts will be very useful in the future, & i will try to adapt this method of calculating the limit or amp targets on led’s next time i need it.
I have tried before, but i am glad i failed that time because you showed me i did it mostly wrong anyway
Would you estimate that, a 18awg wire bypassed spring with wire bypassed omten switch board & the led mcpcb negative running straight through the soldered mcpcb to brass pill :bigsmile: ;), with a 18awg wire bypassed copper spring for the bat + , still be 0.15v or could i hope for even less?
The only thing i can think of to lower the resistance further, is upgrading the omten to the 6A Ebay switch or even better the Judco 10A switch if i just can get some.
And using some NO OX ID on the threads on the brass pill/aluminium tube threads & learning how to solder the switch ground (if that is the right word) to the aluminium tube somehow.
Anyone tried XP-L (no D-D) with FET? I only managed to achieve 4.2A which is far from 200Kcd.
Really thanks for testing that, i am very curious about the results of this.
I have built my 1504 as wrote in the reply to djozz, i will do a real post about it with pictures soon.
How do you mean no D-D, are you talking about Led4powers linear FET driver? Because normal FET driver like the BLF17DD would be considered a DD driver.
Which XP-L did you use, flux & hue bin?
My BLF17DD driven XP-L V6 3C pulled about 4.4-4.5 amps dedomed in a 1504. Measured output was something like 225kcd if my memory is correct. I posted results earlier in this thread.
I had an XP-L that pulled higher amps and had higher kcd but the LED was damaged. I haven’t tried another one since
KKW, was that with the 6A ebay switch & wire bypassed switch board like those you sold recently, or was it with the stock switch assembly, sorry if i have already asked this i don’t remember if i had or not.
It still kills me that a “damaged” LED produced more output. Any chance you could start feeding your dog a diet of Noctigon mounted LED’s? He may get even better results with more practice. :bigsmile: