To OP: please excuse this related discussion. It got longer than intended. It does relate to one way to deal with one kind of problem in an MJ-808, so fits here. I hope you agree. No intent to steal the thread.
What about SST-90 ? can you drop your 0.02$ on it ??
OK gave me an excuse to look at it. It's CRI (color rendering index is 70 which sounds a little low to me as the CREE XP-G is 75 and is OK but some think it too white). The warmer tint, higher CRI SST-90's have lower output. Some people see with warmer light better, so for them less lumens and higher CRI, is more.
Using the stock MJ-808 driver at 2.4-2.5 A you get 75% of the output at 3.15 A. Since the binning rarely hits the high side, let's say 75% of 1000 lumens or about 750 so you are the same as the P7, if the P7 isn't one of the best, and worse if it is. If you got lucky you might get 900 from a really good SST-90 comparable to a really great P7.
Cranking the amps up for more light means even more heat, than light. Though that is one of the straightest lines I have seen plotted for Amps versus % of standard measure lumens (100% at 3.15 A, usually more heat than light above that and more curved above about 50-75% of max.)
5 A gives you about 3.5 Vf for 17.5 Watts, about 15 W of that as heat, and 150% or 1500 lumens. So a better choice than the SST 50 it terms of heat and light out. BUT that would still be almost double the heat of a P7 AND you'd need a 5 A driver (preferably in an attached housing off the back well connected to the back of the driver mount so you can have temp monitoring). NOT easy. And the reflector may not work well with it after all that work!
Compared to that, a little heat sink work for the unit below would be easy.
They tell me it will not work in the 808 ...
I saw your post right after I posted in this thread above. Read MTBR forum again. Short answer is why not, if you have one? Or like me, can't hope to make as pretty a package from scratch although, you can cobble the innards fine.
I think this is a brilliant upgrade path beacuse you don't have to house a driver.
IF you like/have the housing. BUT it wouldn't be a plug and play kit. You will end up about the same cost as a second light head from Geoman, maybe a bit more, though you should have more light better heat management, and an upgrade system if he stays in business making them.
The MJ-808 is a nice small housing, a little too small for optimal cooling. So a new heat sink could easily help. There is a rim (according to that humongous thread here about it) that acts as a ledge to hold the 'heat sink'. That is the only contact point between the body and heat sink and it is not enough thermal path, even with AA on it.
You can grind it out of the way then fit a copper pipe cap to wedge into the tail. That wil be a lot of trial and error, fitting cutting, polishing repeat, but I did it in two different designs for a Bullet shaped Marwi light, so you can do it with no milling machine. My 1" caps were $2 each. The completed light runs very cool.
what about the S2s ? what are they ? when would they be available ?
Not sure how much you have read. A search on S2 would have been too short for keywords to Google it. But by now you should know that LED's are 'binned' by a number of things. White power LEDs are binned by tint and their output range. This is usually a letter/number and specific to each manufacturer and even family of LED's by a manufacturer.
Currently, the CREE XP-G R5 is the highest output bin we can buy in that model. It ranges from 138-144 lumens per Watt at 300 mA. A random one is likely closer to the 139 than the 144. Cree has been making some S2's available to manufacturers and that usually precedes the release that are higher output again. (See link below and look it up to see for yourself.)
The XP-G family was released October 25 2009, I think but samples had been available for months, at least since July. So the S2 may be here by early summer in the Northern Hemisphere.
You can look it up in the binning documentation for the XP-G and other CREE LED's that you can find links for here (or on the CREE site):
http://www.cutter.com.au/categories.php?cat=Cree+LEDS
CREE also have a 200 lumens/watt beast on its way, but figure no sooner than the fall for it and we don't know much about it like whether it will work with available reflectors and optics. (I may have missed a thread or 2 on it, though.)
So, no sweat, if you don't get it right this time, you can mod it again, and again!
), but this is extremely rare.
