Difference between Cree P4 and Q5

I just bought a cheap 3xAAA Cree Q5 torch from DX, however the back of the star says P4 written on in felt tip pen. How do I tell if this is a Q5 as I thought I was buying or just a P4?

Looking at the my P5 LED and my Q5 drop in I can't see any visible difference.

Wire the LED directly to a CC power source and measure the lux with a lightmeter. Use this to get a lux/watt value. Do the same to your Q5 and compare. It's a lot of hassle for not much gain.

Also, P4 vs Q5 doesn't always result in the Q5 being brighter- if the P4 is being driven hard, then it'll put out more light than an underdriven Q5, though the Q5 will be more efficient.

ecotack said:

I just bought a cheap 3xAAA Cree Q5 torch from DX, however the back of the star says P4 written on in felt tip pen. How do I tell if this is a Q5 as I thought I was buying or just a P4?

Looking at the my P5 LED and my Q5 drop in I can't see any visible difference.

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I have both a P4 from DX and a Q5 from Solarforce on ebay. I do notice a difference when comparing my P4 in my Surefire G2 with alum head to my Q5 in my Surefire 6P. The P4 has a more floody beam with hot spot that blends in smoothly. The Q5 has more throw and tighter hot spot. I guess either one is fine depending on how much harder one is being driven over the other despite the category of P,Q or even R bin crees. Either way it's plenty of light to serve it's intended purpose.

If the LED has only three bond wires then it's a P4. The reverse is not true - not all P4s only have three bond wires, so if yours has four I've no idea what it is.

lightinsky said:

The P4 has a more floody beam with hot spot that blends in smoothly. The Q5 has more throw and tighter hot spot..

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This is a function of the reflector, not LED. Just thought I'd clarify

Brightness BIN is a measured performance criteria for each emitter. It can only be measured, provided one has the right ($$$) equipment. Therefore among 4-wire XR-E emitters it is not something that can be physically inspected for.

FWIW... DX6090(XR-E P4) on the left and DX11836 (XR-E R2) on the right. For all practical purposes an R2=Q5. Both emitters driven with the same driver and reflector.

A Cree Q5 should be about 33 % brighter than a Cree P4 for the same current. I do not think there is any visible difference between them.

They all have 4 wires.

My torch with the Q5 drop in is much brighter, but I would expect that, because it has a driver and two CR123s, the cheap torch has a resistor and 3 x AAAs.

Can't take the Q5 out of the drop in to compare at same current, but I can compare it with the P4s I bought. I'll have a go tomorrow. Perhaps with all the LEDs I play around with a light meter may be a handy tool.

jenskh said:

A Cree Q5 should be about 33 % brighter than a Cree P4 for the same current. I do not think there is any visible difference between them.

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You can see a difference in brightness between my P4 and Q5 but it's not dramatic. So a R2 won't be noticably brighter than a Q5 but will be ove an P4 since Q5's and R2's are pretty much the same output.