6p brighter than G2 with LED drop-in?

pbs357 · Aug 19, 2008

Not sure if I'm going blind or my eyes are playing tricks on me or...???

- I have 2 Q5 LED drop ins. One is in an old 6p, and one is in a G2Z with an older 6p bezel (no retaining ring).

- Tint differences aside, the drop-in in my 6p is noticeably brighter in overall output (particularly spill) than the G2Z. HOWEVER, when I swap the modules between the two bodies, the output seems about equal and the "brighter" module no longer stands out.

Is there any conductivity difference between these two designs that could affect output? The only thing I can think of is that the 6p lens I've recently replaced (though the one on the G2Z is mint, free of scratches). Any ideas? :thinking:

Niconical · Aug 20, 2008

This is just a guess, but maybe it could be that due to slight manufacturing variations in the drop-ins and/or the lights, the "less bright" one is actually just sitting slightly lower when in the G2Z, thus reducing the spill and apparent brightness?

pbs357 · Aug 20, 2008

That's an excellent idea, but the spill sizes are the same - I mean the variance in spill intensity/brightness is what I really noticed.

divine · Aug 20, 2008

Usually LED's don't perform as well in nitorlon bodies because the material's ability to conduct heat away from the LED.

Are both of them less bright in the G2Z?

Q5 is just a rating for the performance of the LED... there is a range. A Q5 is defined as an LED that produces from 107 to 114 lumens when running at 350mA. It could be that one is at the high end and the other is at the low end... or maybe one is out of the Q5 range.

Are they the same identical drop-in? Is the light coming out of the LED's the same color? (If it is lower color temperature, or more yellow, it usually puts out less light and appears to be dimmer.)

:candle:

brighterisbetter · Aug 20, 2008

This may be a stupid question, but were batteries also swapped between bodies when swapping drop-ins?

pbs357 · Aug 20, 2008

They are the same DX R2 module, one is a bit cooler and seems brighter than the warmer one. But when the cool one is in the 6p vs the warm one in the G2Z, the cool one is significantly brighter. When I swap and put the warm one in the 6p and the cool one in the G2Z, the output seems similar.

Definitely not a stupid question re: batts, as one set were AW cells and the other are protected generic rcr123's. When I did the original swap, all I did was switch drop-ins. I did later try the original setups while swapping batteries though to see if one set of batts were somehow pushing more voltage, but the difference is definitely the 6p vs the G2Z... so confusing!

Not an earth shattering thing, both are very useable in either setup - I just don't know much about current and electrical path so I didn't know if the aluminum vs. Nitrolon with aluminum battery tube made any difference.

Bullzeyebill · Aug 20, 2008

You pose an interesting question. It could be that there are some resistance differences between the body of the G2Z, and the 6P that would cause differences in output between the P60 in the two lights. There might be (and this is a guess) more resistance in the G2Z with its thin metal sheath in the Nitralon body. I can't find my G2Z right now, but when I do I will check resistance.

Bill

precisionworks · Aug 20, 2008

Remove the tailcap and use a DC ammeter to complete the circuit. Most likely, one emitter has a higher forward voltage than the other, resulting in different amp draw & unequal lumen output.

If you have (or can borrow) a light meter, do a ceiling bounce & record the readings - that will give you a way to calc the percentage difference.

Some drop ins have really strange behavior. I have one that starts out around 200 mA draw when cold, and slowly ramps up to 400mA in about 30 seconds (6P body). The 400 mA is well regulated, and the draw stays level for as long as I've tested - fifteen minutes.

pbs357 · Aug 20, 2008

Bullzeyebill, thats kind of what I was thinking, though until now didn't think it would make a difference. But I guess with all the resistance mod the hotwire guys do maybe it does? I don't have a lightmeter or ammeter, just a cheap $14 voltmeter to check my rcr's voltage.

mdocod · Aug 20, 2008

The heat sinking difference between the plastic and the metal would not have any effect on the difference in output initially, that would only start to have an impact if the lights were left on long enough to heat up the entire module quite a bit, at which point the body does make a difference.

The battery difference and potential resistance in body also shouldn't make any difference either because both modules are buck regulated, if the body had more resistance, the module would just operate at a lower available voltage and higher inlet current to compensate. The resistance would have to be pretty significant, enough to drop the ~7.4V of the cells down below the point where the module drops out of regulation, which is somewhere between ~3.8-4.5V in most setups...

So bottom line- you are seeing things

I'll share with you my experience on this type of confusing situation:

I've found that sometimes the feeling of the light in the hand can make a light "feel" brighter than an alternative. When a light is small and handheld, but a total screamer, it can *feel* brighter to me than a larger light that is technically putting out more light. I think it has to do with expectation levels set for certain size and or styled lights in our brains.

Eric

pbs357 · Aug 20, 2008

Wow! Didn't expect to see you in my thread! Well I'm certainly not going to argue with mdocod thats for sure!

I think I'm gonna see if I can bum a digital camera off of someone and do my first ever beamshots. Until then, I'm guessing case closed... Thanks for all the input and replies guys!

mdocod · Aug 20, 2008

I wouldn't call it case closed, I've been wrong before

but it's an idea.

foxtrot29 · Aug 20, 2008

mdocod said:
The heat sinking difference between the plastic and the metal would not have any effect on the difference in output initially, that would only start to have an impact if the lights were left on long enough to heat up the entire module quite a bit, at which point the body does make a difference.

The battery difference and potential resistance in body also shouldn't make any difference either because both modules are buck regulated, if the body had more resistance, the module would just operate at a lower available voltage and higher inlet current to compensate. The resistance would have to be pretty significant, enough to drop the ~7.4V of the cells down below the point where the module drops out of regulation, which is somewhere between ~3.8-4.5V in most setups...

So bottom line- you are seeing things

I'll share with you my experience on this type of confusing situation:

I've found that sometimes the feeling of the light in the hand can make a light "feel" brighter than an alternative. When a light is small and handheld, but a total screamer, it can *feel* brighter to me than a larger light that is technically putting out more light. I think it has to do with expectation levels set for certain size and or styled lights in our brains.

Eric

Or maybe the lens is dirty in the G2.

Al Combs · Aug 21, 2008

This wouldn't explain the brighter LED from the 6P having the same output as the dim one from the G2 after the switch, but I thought this was interesting.

Here is a test chevrofreak did of an actual P60L dropin going between a G2 and a 6P. Like divine pointed out, plastic being a good thermal insulator traps the heat in the light. And as mdocod pointed out, initially the output in both lights was the same. It took ≈ 15 minutes for that difference to max out. The interesting thing was how great a difference it made! To drop from 77 lumens in a 6P body to 58 in a G2 is almost a 25% drop in brightness.

So I guess based on chevrofreak's test, the electrical resistance theory doesn't hold. Unless there's something wrong with your light. Or like foxtrot29 said, dirt on the lens?:thinking: If you figure it out, be sure and let us know.

Sgt. LED · Aug 21, 2008

The max brightness between the exact same lights here at my house is similar.

I have narrowed the phenomenon down to either lack of sleep, if I have to pee (and how badly), and/or the amount of Mexican food in my diet that day. Testing is still ongoing......
:shrug:

precisionworks · Aug 21, 2008

Another consideration is the manufacturing tolerance that Cree allows on the XR-E lamp, which is +/- 7%. In the most extreme case one lamp could be at the high end, the other at the low end, which is a 14% brightness spread (100L vs 86L, for instance).

Al Combs · Aug 21, 2008

Here's a possibility I didn't think of at first. First of all pbs357 never said how long he ran his comparison test. It might have been long enough for heat to become an issue. The question is not so much why going from one flashlight to the other makes a module behave different, but why you don't always observe the G2 being the dimmest after the switch? When chevrofreak did his test he was using the same module measuring output with his homemade integrating sphere.

But pbs357 had two modules. Were they the same? Two of the same thing would be hard to explain. But I'm wondering if you had two different P60 LED drop-ins and one of the regulators is equipped with a thermal protection moudule...

JNewell · Aug 21, 2008

Two of the same thing would be hard to explain.

Even in that case, as noted earlier, there are manufacturing differences and variations that could cause a noticeable difference.

divine · Aug 21, 2008

Sgt. LED said:
The max brightness between the exact same lights here at my house is similar.

I have narrowed the phenomenon down to either lack of sleep, if I have to pee (and how badly), and/or the amount of Mexican food in my diet that day. Testing is still ongoing......
:shrug:

Excellent work! Keep us updated... :popcorn:

roymail · Aug 21, 2008

Although it's an illusion, a bright white beam will have the appearance of being "brighter" than a WG (for example).

When I received my M60L which is a Q5 WG driven a 300-350ma, at first it appeared to not be as bright as my 6090, a P4 driven at approx 600ma.

When I did a comparison, I discovered a couple of things which contributed to the illusion. One was that the M60L does not have a bright hot spot like the 6090, and the other is that it has a neutral warm tint that is spread out.

However, the M60L gives as much output or more than the 6090 when compared side by side using the same batteries.

So the human eyes and brain can be tricked like this. Just my experience.

6p brighter than G2 with LED drop-in?

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