Cree MC-E (4S) at 1000mA too high?

[marcopolo]

Hi All,

I have a quick question on the Cree MC-E that I haven't seen
addressed: The dies are only rated to 700mA but has anyone tried running them at 1000mA with a good heatsink?

I've got a mixture of stuff coming from cutter (including MC-E on 4S board) and was going to try run this off the bFlex UIB2 - the BFLEX should 'see'the same as the 4up XR-E i'm also getting. I realise it's a bit pointless if i'm getting 4up XR-E's anyway but I was thinking of using the MC-E for a small headtorch used mostly on low setting but the ability to 'supercharge' the light for brief periods say a few minutes @ 1000mA
Is it doable and safely not dmage the MC-E?

Thanks,

Marco.

 

[Gryloc]

The 700mA is a recommended value, but if you can keep the junction temperatures below the max rated, then 1000mA will not hurt the emitter. At 1000mA, that is almost 5W more than you had from the start, depending on the forward voltages. This would require not only good heatsinking, but also very good thermal contact between the MC-E and the heatsink. I am not familiar with the thermal conductivity of the overall MC-E MCPCB star, or how the MC-E is attached to the star. The P7 can handle way over 700mA per die with good heatsinking, but it is easy to attach the slug of the emitter directly to the heatsink with AA epoxy.

In my light, I plan on driving the MC-E above 700mA (probably with the MCPCB star cut down) if my light would be able to pull away the heat, but I am less concerned about longetivity because my flashlights would not be used for thousands of hours. Within a few thousand hours, I should have another higher-binned MC-E, or some fancy new emitter of the future, ready to replace my current MC-E.

In your case, 1000mA for a short "turbo" mode, I see absolutely no problem. If you are concerned, once you get the MC-Es and solder them up, then test the emitter temps. You can monitor the temps of the back of the MC-E by soldering a thermocouple to that little tab sticking out from the side of the slug pad on your MC-E star board.

Of course, if this is for fixed lighting for countless of hours without the option of replacement in years, maybe 700mA is a good starting point.

Monitor this thread in the next coming weeks:
http://www.candlepowerforums.com/vb/showthread.php?t=89607&page=8
I sent some MC-Es and P7s to jtr1962 for lumen testing. You can judge if it is worth the extra heat for the extra lumens by driving each emitter with an extra 300mA. Luckily, compared to most single die emitters, the efficiency is pretty constant between .7A per die and 1A per die (only about a 10lm/W decrease).

Good luck!

-Tony

 

[spencer]

Running it at 1A might be a little too much with it attached to a star. I'm pretty sure the star is very poor at conducting heat compared to say....straight aluminum.

 

[steve6690]

I can't see the point in running at 1A. In my 6 x Q5 light I can't tell any useful difference between 700ma and 1000ma.

 

[marcopolo]

Thankyou for the info.

I believe it is a round board, not Star with the emitter pre-attatched - I don't know if star vs round will make a difference to the heatsinking.
(anyone ever tried filling the front end with oil as cooling before?)

Steve, if i'm using a 'pill style' module to swap my bFlex between my 4up XR-E and my MC-E then I would rather not change the programming on the bFlex to lower the current to 750mA - plus it gives me that bit extra boost. A friend showed me his 3up Q5 XR-e and I could tell the difference between 750mA and 1000mA, but like I said I just want it as an option for a quick boost. It may just be more sensible to order another bFlex!

Marco.

 

[VanIsleDSM]

I made some special mounting boards for the MC-E seen here:

http://www.candlepowerforums.com/vb/showthread.php?t=206088

I'm away at work right now but when I get home I'll make a few for some CPFers to try out.

These should help eek out as much heat as possible to safely run at 1000mA with good heatsinking.

 

[H20doctor]

I drove my MCE at 1000 ma no problem..... it took it just fine... its way brighter at 1000 than 750 for sure... Make dang sure you have a large heatsink on it cause it gets super hot mounted on a star PCB..

 

[Wilkerson Brasil]

Is it safe mount an MC-E WG-K0 (http://www.dealextreme.com/details.dx/sku.16145) in a Raidfire Spear?

Spear driver works at ~1.3.

If I try this setup will I fry my led and my 20 bucks?

Thanks

 

[Jarl]

The spear driver won't be able to raise the voltage high enough to power the MC-E.