Emitter Choice 7*Q5 or 3*P7

Three underdriven P7's would generate less heat, and will typically have a lower Vf than the CREE LED's.

They would also be easier to wire. :thumbsup:

datiLED said:

Three underdriven P7's would generate less heat, and will typically have a lower Vf than the CREE LED's.

They would also be easier to wire. :thumbsup:

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The first thing that I thought of when I started to read the thread was that heat will be the last problem. In fact it will be nice to have a light that heats the water around you. Just couldn't resist, sorry!!!

Personally I would go for the P7's. Reasons:
- Only 3 emitters to work with. Less complex to build
- Scope to increase output in future, if required

I'm wondering about the difference in beam patterns, particularly since this is a dive light. The tightest beam from even a single P7 I think that I've seen so far is an Elektrolumens P7 Longthrow over in CPFMP, and that has a big head to house a reflector big enough for creating good throw. I'm wondering if you can get a tight enough beam using multiple P7's in the space allotted?

Well 7xQ5 will probably throw better but harder to work with compared to triple P7.

If you want a good hotspot and the best overall beam quality the Cree's will win hands down over the P7 IMO.

I've used Fraens with Cree's, and the beam was "ringy". The McR19XR's are head and shoulder above in beam quality.

I would use 7 Cree's with McR19XR reflectors. Expensive and more difficult to build, but you'll forget about all that once you turn it on.

If you want a cheaper option, do 7 Seoul U2SWOH stars and IMS 20 reflectors. Those reflectors give a nice beam with a Seoul emitter.

Thanks for the replys, good points made.

I had forgotten about the IMS 20 reflectors, they do include legs that support the reflector but probably not as securely as the Fraen ones that positively snap onto the ring of the XR-E.
I have used the Seuol P4 with Prolight reflectors (26mm) to good effect so I can believe they give a good beam.
Is there anywhere these can be got for less than $4 each?

I think the only way I will resolve this one is to get a P7 and put it in the reflector I am thinking of and see what the beam is looking like.

Will try to pop over to our local engineering shop to get some off-cuts for a heatsink.

Nick

The Cree optic has a tighter beam than the Fraen optic. I do not have a Fraen reflector light.
Fraen optic left, Cree optic right.


Reflectors put a lot of light in the spill. SSC-P7 has a fairly wide hotspot.
L-mini Q5 left, MTE SSC-P7 right. Both with reflectors.

This post https://www.candlepowerforums.com/threads/201307 shows a photo of the Kahod reflectors beam.
A little strange as it has a kind of donut of Dark between the hotspot and the spill.

On the above post the cree optic looks nice, I could just fit in the optics but not the housings also unless I dropped to 5 xr-e.

Just got back from the Machine shop. They are going to make me a couple of heatsinks for me :laughing:. I knew they did not have a (working) lathe so nearly did not go round, but he is going to "turn" the puck shaped heatsink on the CNC MILLING machine - That is clever.

To continue my indecision I have asked them to make up two heat sinks
If all goes well. I get the first one to work and mod a torch for a friend.

Nick

The dark donut is common with all Cree XRE lights. Most flashlights now have orange peel reflectors to minimize the effect.

Doh!Nut said:

This post https://www.candlepowerforums.com/threads/201307 shows a photo of the Kahod reflectors beam.
A little strange as it has a kind of donut of Dark between the hotspot and the spill.
Nick

Click to expand...

I would go with the CREEs.

I'd also recommend the OP aluminum reflector from DX, it's only $2.33 and works excellent.

Here's the Fraen reflector from cutter for $1.12USD
http://www.cutter.com.au/proddetail.php?prod=cut738


Here's the OP DX reflector seen here:
http://www.dealextreme.com/details.dx/sku.5951


Fraen has a slightly tighter beam with more intensity right in the middle, but you can see the donut quite easily. I really like the DX reflector, smooths the beam well and has nice spill.