I notice a difference. Maybe I am too sensitive, but I notice the difference indeed. I want the next 18 times I click on a light to be the same in brightness as numbers 1 and 15, etc. Lights like Fenix and Lumintop have spoiled me to the hackneyed mod jobs that blaze off the finish line as DD lights, and then taper off gradually.
Of course, I’ve used several lights that are DD and I enjoy them, but my new buying habits have me reaching for the upscale regulated ones. I find myself having to top off DD lights (or else thinking of having to top them off again) too soon. My mind needs the peace of knowing that my tool is there for me in full capacity each time. This is why I HATE most all lights that have a four-second delay for mode memory to activate. I need dependable, predictable performance each and every time, period. End of story.
It’s like I train my employees: Consistency of service is to be valued as much as a high level of service. One shouldn’t come to my property and have to hope that a nice employee is there so that he can ask for and get extra amenities coming his way. The standards for who gets what under which circumstances should be clear and enforced universally, so that policies can be enforced consistently. I should never hear: “Well, the last time I was in line, the other girl [employee] let me ride this ride!” “I’m sorry, sir. That associate was acting out of policy. Our rules state that a child must be tall to ride this ride. Our insurance is clear about this matter…” Great service is only as good as far as it is consistent.
Well, sorry for the tangent, but you now clearly see where I’m coming from! :-B
I have 2 XHP70 powered lights and both of them can run forever without overheating in the L6 and S70. It gets warm to the touch but not hot enough to damage anything. Even modded they still stay cool enough to run for extended times without over heating.
I have an S70 that runs between 9-10amps on Turbo, and it can handle the heat for a few minutes just fine.
6A x 4v x 3Leds = 72w
9A x 8v x 1Led = 72w
When you are pushing a light to max output you normally don’t need it to run for very long. If you need long runtimes, you use a lower mode or get a bigger light.
There are plenty of people running 10+amps through a triple XP-L in a little convoy host. They know you can’t run it on turbo for very long, but that’s what low is for.
You and I could build identical lights: identical hosts, identical emitters. The only difference is you limit your driver to 5amps total, and I let mine run over 10amps on the highest mode.
We can both run our lights at 5amps if we want, but I could also run mine brighter in short bursts if I wanted to, you could not.
Convoy L6, XHP-70 P2 bin, 11.7A at 7452 lumens. Actual out the front lumens and tail current, usable light… my walk the trash to the road on Thursday night light, it’s a 700 yd walk. Usually run it about 10-12 minutes every week at Turbo levels.
SanMarcos, the party town, consistency you seek? Interesting. A regulated light is nice, indeed, but misleading. You say you want the 15th click on to be the same as the 1st or 2nd, that is a misleading concept, as the cell will be taking a hard hit as you approach the 15th click and won’t last but moments, depending of course on how long you’ve been running the light on earlier runs. It’s my opinion that regulation damages cells, drawing the most current when they’re nearly depleted and hence shortening their life cycle dramatically. Tit for tat, as it were. When your cell reaches the end of life in a cycle due to regulation, your light goes out and leaves you in the dark. A direct drive light lasts a very long time, you’ll know quite in advance before it finally shuts off and darkness ensues. You simply cannot have your cake and eat it too.
Perspectives, of course, virtually always dependent on usage type.
Keep in mind if you do push 3x XHP-35 HI hard in this light it will overheat if you aren’t paying attention. It’s a large light, but that is a LOT of heat being generated.
As long as you are holding it balanced though you should be fine. Your hand will be close or touching the lowest heatsink fin and that will definitely tell you to kick it down a notch or two.
And that’s precisely why I like regulated lights (and generally, 1-mode, too ). I gotta agree with Rusty on this one.
Me, I prefer the constant current and consistent light output. Whether the cells are right smack out of the charger, or on the brink of dropping out, the light’s the same. When it does start dimming, that’s when I know it’s time to recharge or swap cells.
When it’s a constant slow falloff, then without a meter or something, I can’t tell how far down they are. Even a change in ambient light will confuse pretty much anyone as to the “brightness” of the beam.
Also, changes in temperature will affect forward voltage of the LED, resistance in the wires, a whole bunch of other factors. Just crowbarring an LED across a cell of variable voltage and other variable conditions can change the current through the LED, maybe way different from what was measured on a testbench.
Hey, for the brightest light possible, sure, crowbar the LED right across the battery, no problem. Don’t think anyone’s saying DD is “bad”, per se, but that it’s so… variable.
That’s why as much as I love my Quark’s UI, just the fact that it uses alkie AAs and turbo ends up dimming to high… then turbo and high dim to medium… then turbo and high and medium dim to low… makes me dislike using AAs for anything but when they’re pretty much fresh out of the package. The slightest bit of “wear”, and I end up feeding the cells to my little beat-to-Hell 1×AA light and burn them down to nothing.
And for my main carry, I go back to my 1-mode ’502 and be done with it.
Actually, just the opposite. A DD FET “saturates” at an extremely low voltage, from the extremely low Rds(on) of the FET. A 7135 just saturates at a fixed 0.1V or so.
Eg, assume a 10mΩ FET, or something similarly beefy. At currents like 2A-3A, that’s only 20mV-30mV (0.02V-0.03V)! So if Vb is 3.0V, with the 7135, the LED sees 2.9V. With the FET, the LED sees, well, just shy of 3.0V! So the current drawn in DD mode is larger than the current drawn through the 7135+LED.
Point is, you’d have to be drawing lots of amps through the FET for the dropped voltage to equal the ~0.1V of the 7135.
Hm? At a high voltage, the 7135 will only draw 350mA (nominally), and its voltage will be the difference between the battery’s voltage and Vf of the LED (eg, 4.2V - 3.6V = 0.6V).
As the voltage dips, the 7135’s series voltage gets lower and lower, until it saturates at around 0.1V. At that point, the regulator is effectively DD! As the battery’s voltage dips further, available voltage to the LED also drops (Vb - 0.1V) and the current drawn is a function of the I-vs-V graph of the LED.
With the FET crowbarring the LED right across the battery, Vf ≈ Vb. Through the 7135, Vf ≈ Vb - 0.1V.
So the battery takes a bigger hit with the FET than with the 7135.
). I gotta agree with Rusty on this one.