Seoul Cree in an L5? What resistor would you need?

Its my understanding that the new Crees' would not be able to handle the power given it by the regulator board in the L5. So my question is what value resistor would be needed to "knock down" the current/power to the max safe level. My vision is to somehow isolate the negative contact spring, then run a resistor from the spring to the contact core so you could run a Seoul Cree in a L5 without having to mess with the driver board. Similar to the McE2S 2 stage switch. I even have an idea about running both . Any ideas?

how about a second cree in series? that should up the Vf to lux V lvl.

You don't want the constant McE2S 2 stage switch on low mode, since that's unregulated.

Edit: sorry for double post, wrong button

pokkuhlag said:

You don't want the constant McE2S 2 stage switch on low mode, since that's unregulated.

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I don't think thats' true. I remember seeing a graph of an L4 with a McE2S 2 stage switch (60ohm) showing somewhere near 9hrs runtime on low and looked pretty regulated to me. Maybe someone could clear it up?

I've also considered mounting a Cree in a new KL3 head since it would certainly handle the power in that.

KDOG3 said:

I don't think thats' true. I remember seeing a graph of an L4 with a McE2S 2 stage switch (60ohm) showing somewhere near 9hrs runtime on low and looked pretty regulated to me. Maybe someone could clear it up?

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Nope, McE2S is not regulated on the low level. It's simply a resistor in series with the battery.

Jan

Arrrrrgh. You guys are KILLIN' me!!! Back to the drawing board.... I guess I can still consider the KL3...

Could help:

Resistor calculator for leds from MetkuMods - Because you love your hardware!

Best regards

____
Tom

If you got the KL5 opened up, why not just replace the boost converter with a Downboy converter? Or am I missing some other intentions?

Is that difficult? I'm willing to consider that, but I'm thinking that would be very difficult.

KDOG3 said:

Is that difficult? I'm willing to consider that, but I'm thinking that would be very difficult.

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Have you gotten the KL5 opened up? If you have, you've done the most difficult part already. One thing I forgot though is that the Downboy will require some heatsinking if you're going to run it hot. One other option (but it somewhat limits your power options) is to use a Wiz2 or GD converter. Their higher efficiencies means that less power is wasted as heat in the converter. But your input voltage becomes limited to somewhere less than 6V. If you are using 17670 Li-Ions or for ocassional 2x123 use, then I would probably go that way.

Very interested in this thread: I'm considering having a KL5 modded (I wouldn't want to try myself) with a Cree/Seoul LED. I would also want to have the stock converter replaced with a circuit board giving several levels, including a strobe mode. Maybe a flupic (I'm no expert- I personally would want to run this light on 2*CR123 primaries)? Have you considered something like this?

Good luck with the mod. Please post details of how well the LED fits in the stock reflector and what the resultant beam is like when you are done!

Wow. Now I dont' know what you're talking about! LOL! I dont' have the KL5, but I've had it in the past. I'm flirting with ideas right now. I'm thinking the Seoul Cree would be ok in the L5 since (I've heard) the beam pattern is closer to a Luxeon.

KDOG3 said:

Wow. Now I dont' know what you're talking about! LOL! I dont' have the KL5, but I've had it in the past. I'm flirting with ideas right now. I'm thinking the Seoul Cree would be ok in the L5 since (I've heard) the beam pattern is closer to a Luxeon.

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The deep reflector of the KL5 will work well with the XR-E as well as the Seoul P4. The biggest issue with the KL5 is that it uses a boost regulator when a buck regulator is what's needed. I have heard that the later generation KL5's runs buck/boost so if that can be verified/confirmed, then you want to get a hold of that version to obviate the need to swap out the converter. Hmmm, now *I'm* flirting with the idea.

Lately, every time I pass by one of my KL5s I hear a muffled sound. As I put the KL5 up to my ear I hear the unmistakable cry....Cree me! :rock:

CM said:

The deep reflector of the KL5 will work well with the XR-E as well as the Seoul P4. The biggest issue with the KL5 is that it uses a boost regulator when a buck regulator is what's needed. I have heard that the later generation KL5's runs buck/boost so if that can be verified/confirmed, then you want to get a hold of that version to obviate the need to swap out the converter. Hmmm, now *I'm* flirting with the idea.

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I don't understand something however, wouldn't the Cree emitter be getting the same power level regardless of what kind of converter board is in there? I guess I don't know as much as I thought I did! How would you know which one you got? I'm waiting for the new product line to come out before I buy anything to see if they go with HA black....

:tsk: :tsk: You guys are cree-zy. :naughty: Don't spoil the wonderful ram of light from the L5 by putting in that tiny little chip. Sure you'll get more throw, but throw isn't everything. I seriously would never do this to my L5. Way too nice a beam to spoil like this IMHO.

Jan

The Kl5 can be ran on 2 cells, so it has to boost for the LuxV. So If you swap a cree with a lower VF (less than 1/2 of the luxV) you now need a step down (buck) convertor. It's been rumored that maybe newer KL5 are both buck/boost but who knows???

The KL6 is meant for 3 cells, so its always buck circuit, and therefore swapping a Cree is easy. Your runtime just doubles.

JanCPF said:

:tsk: :tsk: You guys are cree-zy. :naughty: Don't spoil the wonderful ram of light from the L5 by putting in that tiny little chip. Sure you'll get more throw, but throw isn't everything. I seriously would never do this to my L5. Way too nice a beam to spoil like this IMHO.

Jan

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Hi Jan, have you seen the beam from a KL6 with a Cree? When you do, you'll realize we're not *that* cree-zy The Cree will put out as much light as a Lux V and with the proper reflector, will give an incredible beam. The donuts and crappy beams you've been reading about are a consequence of improper designs or improper modifications. Right now, the only reflectors that I've tried that worked well without modifications are the McR19 and KL6. Other reflectors will work very well but they require the LED to be moved way up into the reflector which means significant modifications to the reflector. The KL5, having similar profile as the McR19 and KL6, should also provide excellent beam.

IsaacHayes said:

The KL6 is meant for 3 cells, so its always buck circuit, and therefore swapping a Cree is easy. Your runtime just doubles.

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I still don't understand. Won't the regulator still pull the same power from the cells regardless of whether theres a Cree or LuxV in there?