Fenix L2D: Worth upgrading from Q4 to Q5?

[etc]

I've had L2D Q4 for a while... great lite.

Very bright for the size. 135 Lumens.

I realize Q5 has 180 lumens, or 45 Lumens more.

Is it a good idea to upgrade? I want the brightest 2AA Lite, but not sure I will even see that extra 45 lumens.

When is the next generation of the LEDs will come out, with another quantum leap? I mean in the 200-300 lumen range?

 

[EXCALIBUR1]

I recently upgraded my L1D CE to an L1D Q5. The L1D Q5 is definitely brighter. You should upgrade your L2D Q4 to an L2D Q5. After all, it's only money.

 

[Handlobraesing]

I've had L2D Q4 for a while... great lite.

Very bright for the size. 135 Lumens.

I realize Q5 has 180 lumens, or 45 Lumens more.

Is it a good idea to upgrade? I want the brightest 2AA Lite, but not sure I will even see that extra 45 lumens.

When is the next generation of the LEDs will come out, with another quantum leap? I mean in the 200-300 lumen range?

Keep in mind binning is a range rather than a spot.

4sevens stated P3D drives its emitter at 0.8A*1 If it's driven at the same current on the L2D, you can expect that the LED will emit approximately 1.8 times the 0.35A spec.

From CREE:
0.35A specs:
Q4: 100-107
Q5: 107-114

At 0.8A drive and before thermal derating, you can expect 180-193 emitter lm from Q4 and 193-205 emitter lm

From what I can tell from the datasheet, the best case gain (if you have the bottom of the bin Q4 and you get the top of the bin Q5) is 14% measured and no gain in the worst case. Taking the ratio of mid-range of both, I'd say more likely gain is around 6.8% measured.

It is understood that our perceived brightness can be approximately represented by "square law".

In worst case, there is zero gain.
In likely case, there's sqrt(1.068) or 3.3% perceived gain
in best case, 6.8% perceived gain.

I would certain not buy a whole new light in a hope of gaining 3.3% of noticeable brightness.

*1 http://www.candlepowerforums.com/vb/showpost.php?p=2221090&postcount=32

 

[Curious_character]

I've had L2D Q4 for a while... great lite.

Very bright for the size. 135 Lumens.

I realize Q5 has 180 lumens, or 45 Lumens more.

Is it a good idea to upgrade? I want the brightest 2AA Lite, but not sure I will even see that extra 45 lumens.

When is the next generation of the LEDs will come out, with another quantum leap? I mean in the 200-300 lumen range?

I seriously doubt that you'll be able to tell any difference. I've upgraded a number of Cree lights, but from P4 or Q2 to Q5, which is worthwhile.

One other point -- a lot of the Q5 emitters I've seen aren't really more efficient than a Q4. They just have a higher forward voltage so they produce more light (but consume more power) at a given current. So if you "upgrade" to a Q5, you're likely to find that the run time decreases by just about the same fraction as the light output increases.

c_c

 

[etc]

Thanks for putting things into proper perspective.

I think I will keep it until I either loose it, break it or give it away - no immediate plans to do any of it yet.

 

[Handlobraesing]

I seriously doubt that you'll be able to tell any difference. I've upgraded a number of Cree lights, but from P4 or Q2 to Q5, which is worthwhile.

One other point -- a lot of the Q5 emitters I've seen aren't really more efficient than a Q4. They just have a higher forward voltage so they produce more light (but consume more power) at a given current. So if you "upgrade" to a Q5, you're likely to find that the run time decreases by just about the same fraction as the light output increases.

c_c

CREE doesn't rate the output by power consumption, but current, so efficiency is not part of the binning requirements.

CREE gives 3.3v typical and 3.9v max for [email protected]
3.7v typical at 1A, but no max spec given at 1A.

 

[jirik_cz]

Do you really have L2D Q4? Or do you mean L2D P4? L2D Q4 should have more than 135 lumens on turbo.

 

[TONY M]

I see that FENIXSTORE advertises stock heads.
Link https://www.fenix-store.com/index.php?cPath=27_41
None in stock at present though. I assume the heads are upgradeable?

 

[etc]

I have L2D-CE, that I got last year from Fenix Store. It's whatever came before Q5 I presume.

 

[Gunner12]

The P4 came before the Q5(big difference between the P4 and Q4). There was also a special Q2 run but that was short lived.

From P4 to Q5, there should be around a 30% increase in output(noticeable, but not significant). If you think that is worth the work, then go for it.

 

[PlayboyJoeShmoe]

I don't know about CE to Q5.

I have two examples of up-rated lights.

I have a LOD Q4 and a LOP SE(LUX) the difference is staggering!!!!

I have an older P1 LUX and a P2D Q5. Again the difference is staggering!!!

I have some pretty bright P4 lights, and P2D Q5 does not blow those out of the water.

But as an L1D Q5 I think I'd be pretty hard pressed to come up with a better EDC for MY needs.

I can't see where you'd need to upgrade to a Q5. I can completely understand WANTING to....

 

[etc]

Sorry, I meant L2D-CE P4.

The original question should have said -

Fenix L2D: Worth upgrading from P4 to Q5?

 

[Crenshaw]

P4 to Q5 is a whole letter worth of upgrade, which i think is the minimum when you want to upgrade the emittor.

Crenshaw

 

[Curious_character]

P4 to Q5 is a whole letter worth of upgrade, which i think is the minimum when you want to upgrade the emittor.

Crenshaw

I agree. I've done that upgrade to several lights. You get a 30 - 35% increase in light output, which is just about enough to barely notice.

c_c

 

[Badbeams3]

I try to find someone to give my old light to...assuming it`s in good shape. Justifies getting the latest one out...I have a birthday coming up...

 

[Gunner12]

I try to find someone to give my old light to...assuming it`s in good shape. Justifies getting the latest one out...I have a birthday coming up...

If it's in good shape, give it to a good friend or family member.

 

[PlayboyJoeShmoe]

My LOD Q4 tells me there ain't nothing terribly wrong with Q4s.....

 

[Crenshaw]

I try to find someone to give my old light to...assuming it`s in good shape. Justifies getting the latest one out...I have a birthday coming up...

thats what happened to me LOD-CE....except someone offered to buy it from me...of course i was happy to sell it...

Crenshaw

 

[TORCH_BOY]

I have both and the difference in brightness is not much.

 

[etc]

Can you quantify the difference?