Fenix, L2D ce vs L2T vs P1D ce

[dwminer]

Sorry had the meter set at 10x, so i decided to redo testing. Similar results, but not quite the same.

Batteries used in the L2Dce and L2T were Rayovac HyBrid charged 4 hours earlier. I used my Meterman LM631 at one meter distance from the light and moved it around until I got the highest reading.
L2D
turbo.............2050 lux
stage one........128 lux
stage two........581 lux
stage three....1158 lux

OK, as requested with one dummy cell and one rechargeable
turbo................1204 lux
stage one...........123 lux
stage two...........551 lux
stage three.......1106 lux

L2T
High.............829 lux
Low..............174 lux

P1D wife took it, but its bright.
New surefire battery
Max.............2000+ lux
High............1005 lux
Low...............203 lux
Tried a used Titanium battery and got the similar readings.


Well that's what the meter showed, your milage my vary.
I have to tell you that I'm blown away by the cree's. After 60 years it's like being biten by the flashlight bug again. If this is the future, I love it.
Dave

 

[Lobo]

Thanks, it's very nice to see a comparision with actual numbers. :goodjob:
Would be even better if you had the L1D also.

 

[MillerMods]

If this is the future, I love it.
Dave

I'd say it's a good introduction to what sort of things are to come. Just wait until we start seeing developments with nano-crystals. They will redefine everything once again.

 

[TORCH_BOY]

I like the comparison, Lights have come along way,
I have the Fenix LOD-CE, its amazing how much light it puts out for its small size

 

[Perfectionist]

Nano-crystals !

Haven't read about those being used to produce light - got a link so I can start salivating !!

 

[TJZ]

Batteries used in the L2Dce and L2T were Rayovac HyBrid charged 4 hours earlier. I used my Meterman LM631 at one meter distance from the light and moved it around until I got the highest reading.
L2D
turbo.............206 lux
stage one........12 lux
stage two........60 lux
stage three....119 lux

L2T
High.............75-80 lux
Low..............18-20 lux

P1D wife took it, but its bright.
New surefire battery
Turbo...........200-205 lux
High............100-105 lux
Low..............20-21 lux
Tried a used Titanium battery and got the same readings.


Well that's what the meter showed, your milage my vary.
I have to tell you that I'm blown away by the cree's. After 60 years it's like being biten by the flashlight bug again. If this is the future, I love it.
Dave

Hi dwminer, Is there a version 2 of the Fenix P1D CE?
Or is this a typo? Or am I missing something?
There is no Turbo Mode in the Fenix P1D CE
unless you mean "Max".

I see you said:

P1D wife took it, but its bright.
New surefire battery
Turbo...........200-205 lux
High............100-105 lux
Low..............20-21 lux

Tom

 

[SKYWLKR]

Can you throw a dummy cell in and check to see what the L1D gonna trow down?

 

[zeeexsixare]

Batteries used in the L2Dce and L2T were Rayovac HyBrid charged 4 hours earlier. I used my Meterman LM631 at one meter distance from the light and moved it around until I got the highest reading.
L2D
turbo.............206 lux
stage one........12 lux
stage two........60 lux
stage three....119 lux

L2T
High.............75-80 lux
Low..............18-20 lux

P1D wife took it, but its bright.
New surefire battery
Turbo...........200-205 lux
High............100-105 lux
Low..............20-21 lux
Tried a used Titanium battery and got the same readings.


Well that's what the meter showed, your milage my vary.
I have to tell you that I'm blown away by the cree's. After 60 years it's like being biten by the flashlight bug again. If this is the future, I love it.
Dave

To back up the lux readings, here are the measurements from the electrical side:
L2D CE current measurements:
New Duracell 2650mAh batts in series, measures 2.70V OC
Charged 5 days ago, stored in 40F fridge since then. Warmed to room temp(~68F).
Low = 70mA
Medium = 230mA
Primary = 530mA
High = 1.07A

 

[dwminer]

Updated the L2D ce with one dummmy cell and one Rayovac Hybrid..
Version 2.0 on the P1D, not that I can tell, but I did see a V2.0 printed on the side of one Fenix light while surfing the web today, but I don't remember which site or what light.

I have 16 Duracell 2650, two have gone bad and several more have very high self discharge rates. I number all my
batteries, and charge each AA battery separately. Light output is the same for fresh Duracell or Rayovac rechargeable batteries. Sorry just had to get that jab on the Duracell 2650.
Dave

 

[paulr]

If you've got some L91 lithium AA cells I'd be interested in a lux reading with those. 4x7 on another thread measured over 900 mA at the LED in an L2D CE with a pair of them (1.6v open circuit voltage). I calculate that with 2xNiMH and your current measurement no more than 600 mA or so is getting to the led.

 

[Curious_character]

. .

P1D wife took it, but its bright.
New surefire battery
Max.............200-205 lux
High............100-105 lux
Low..............20-21 lux
Tried a used Titanium battery and got the same readings.


Well that's what the meter showed, your milage my vary.
I have to tell you that I'm blown away by the cree's. After 60 years it's like being biten by the flashlight bug again. If this is the future, I love it.
Dave

My mileage sure does vary!

Flashlight Reviews shows the P1D as 730 lux at one meter on primary (medium) and the P1D CE as 1400. I don't have a P1D, but my P1D CE measures 1330, very close to the FR reading. Why is yours measuring less than 1/10 that? Perhaps you had your meter set to a X10 scale? Your numbers are useful for showing relative light levels, but they don't seem to be lux at one meter.

c_c

 

[dwminer]

"Perhaps you had your meter set to a X10 scale?" Yup, that's what I did. Thanks for pointing that out. My P1D only puts out 1005-1050 on medium and 2000+ on high. Big difference on high also.
Dave

 

[Curious_character]

One other suggestion -- it's hard to read some lights at one meter. If you have a cheap lux meter like I do, the resolution is only one lux, so you don't get much resolution at one meter with very dim lights. And some lights with a tight beam are very hard to point just right to read the peak value. The beam might even be smaller than the light meter window, in which case you're averaging in some of the light from the weaker parts of the beam. So I take measurements at one of two different distances, 48 and 130 inches (which happen to be the distances between my workbench vise and two walls), or closer for very dim lights, and adjust the readings for one meter. I've tested at a number of distances, and the correlation is very good. All you do is multiply the meter reading by d squared where d is the measurement distance in meters, to get the lux at one meter. For example, the readings at 130 inches are multiplied by (130/39.37)^2, or 10.90. (39.37 is very close to the number of inches in one meter.) So if my meter reads 122 lux at 130 inches, the light level is 1330 lux at one meter. Correlation of measurements of the same light at different distances is a good way to check your meter's linearity.

c_c

 

[Lobo]

A question, are lux readings very hard to do, in the sense of getting them equal? Just wonders since the nr for the P1D CE differs so much from FLR numbers (2000lux compared to 2700lux on max).

 

[Curious_character]

A question, are lux readings very hard to do, in the sense of getting them equal? Just wonders since the nr for the P1D CE differs so much from FLR numbers (2000lux compared to 2700lux on max).

I've measured a lot of lights and compared them to FLR. Sometimes they're pretty close, sometimes quite a ways off. Here are some of the possible reasons for the differences:

1. The meters might not be particularly accurate. However, I generally get close enough readings that I don't really think this is a major factor.
2. Different battery types. I use NiMH almost exclusively for AA and AAA lights, many reviewers use alkaline. The light output vs time curves can be very different for these cell types. Primary and rechargeable lithium cells are also different and will often produce different light levels.
3. Different battery condition. It's very common for the light output to drop 10-30% during the first 2-5 minutes of use with a new or freshly charged battery. So the reading you get depends on how fast you get the light centered on the meter. When I do run measurements, I first position the light for maximum. Then, without changing its position, I replace the batteries with the ones to be used for the test. I usually compare the readings 5 or 15 minutes after turn-on, but most reviewers don't. Alkaline batteries also "bounce back" after a rest, so you can get various readings depending on how long the light has been off between measurements.
4. The lights really are different. Especially with small lights, a tiny movement of the LED with respect to the reflector has a major effect on the focus, which in turn affects the brightness of the main beam. I've increased the lux reading by more than 30% on some lights by changing the focus. Normal manufacturing tolerances can surely cause variations on this order in smaller lights. There's also some tolerance in the amount of current supplied to the LED, and a fair amount of LED-to-LED variation in light output even when the current is identical.
5. Other sources of variation, for example measurement distance. If you mis-measure the distance from LED to meter by 10%, it'll change the lux reading by 21%.

Considering all the variables, it's rather amazing that some measurements are as consistent as they are. I've lost the thread reference, but a while back a single light was passed around to a bunch of people to measure, and the measurements were all over the map. But I still find the ability to make measurements very useful. For the same light I can get repeatability within a few percent, so I can realistically compare the lights I have.

c_c

 

[Lobo]

I've measured a lot of lights and compared them to FLR. Sometimes they're pretty close, sometimes quite a ways off. Here are some of the possible reasons for the differences:

1. The meters might not be particularly accurate. However, I generally get close enough readings that I don't really think this is a major factor.
2. Different battery types. I use NiMH almost exclusively for AA and AAA lights, many reviewers use alkaline. The light output vs time curves can be very different for these cell types. Primary and rechargeable lithium cells are also different and will often produce different light levels.
3. Different battery condition. It's very common for the light output to drop 10-30% during the first 2-5 minutes of use with a new or freshly charged battery. So the reading you get depends on how fast you get the light centered on the meter. When I do run measurements, I first position the light for maximum. Then, without changing its position, I replace the batteries with the ones to be used for the test. I usually compare the readings 5 or 15 minutes after turn-on, but most reviewers don't. Alkaline batteries also "bounce back" after a rest, so you can get various readings depending on how long the light has been off between measurements.
4. The lights really are different. Especially with small lights, a tiny movement of the LED with respect to the reflector has a major effect on the focus, which in turn affects the brightness of the main beam. I've increased the lux reading by more than 30% on some lights by changing the focus. Normal manufacturing tolerances can surely cause variations on this order in smaller lights. There's also some tolerance in the amount of current supplied to the LED, and a fair amount of LED-to-LED variation in light output even when the current is identical.
5. Other sources of variation, for example measurement distance. If you mis-measure the distance from LED to meter by 10%, it'll change the lux reading by 21%.

Considering all the variables, it's rather amazing that some measurements are as consistent as they are. I've lost the thread reference, but a while back a single light was passed around to a bunch of people to measure, and the measurements were all over the map. But I still find the ability to make measurements very useful. For the same light I can get repeatability within a few percent, so I can realistically compare the lights I have.

c_c

Thanks for the answere. Makes me appreciate the work you guys do even more. Reviewing lights isn't as easy as it seems. Keep up the good work!