I wasn’t saying that those tests should have been made with proper testing standards for everyone to see.
I was just wondering how long it was on when you took the measurement and what cooling you used so that I could guesstimate how well it would perform for me if I used a big heatsink.
Something to think about:
Every LED has a thermal resistance, the XHP-70.2 has an Rth of 0.9°C/W, so maybe 1°C/W to the solder joint. This means that for every Watt of heat converted power the LED is 1°C hotter compared to the solder joint. In addition to this you have the heat path to the outside of the flashlight.
At 20A and maybe a Vf of 7.5V (I’m guessing here) the LED gets 150W! EDIT: of which around ~80% is converted to heat (see posts below).
So the LED will be 120°C hotter than the the solder joint on the PCB is.
So if your lights are too hot to hold (pain threshold is at 60°C), the LED is at least 170°C hot.
At this temperature, which is outside the range of the datasheet, the LED loses around 25% of it’s output. Basically a big part of it’s high efficiency is wasted at this point.
The relevant power when considering the thermal resistance is the thermal power. Some of the input power leaves as light and so doesn’t contribute to the heating of the die. So only roughly 50-80% of the input power heats the die.
Right, forgot about that.
At these power levels it might be 20%.
So it’s “only” 120°C more.
I have corrected my post.
I think I have one on order from KD but it has not arrived. But I’m not sure anymore now, I have never made an account there so I can not see an order history, and KD does not send order confirmation emails with details of the items.
If it arrives after all I will do a test, but my power supply does not go over 20A and, as I read above in Kawiboy’s posts, that that is not enough, it is quite a performer!! 
If you have a 12V mcpcb then you can run it in 12V mode which would only need 10A to max it out.
Although while it may survive that high I can guess that running it above ~15A is going to be a matter of quickly diminishing returns to the point of silliness when you factor in the heat it will produce.
[quote=Texas_Ace]
The 15A buck driver you developed is starting to make a lot more sense now. 
You flashlight mad scientist!
Meh, it came as expected . there was so many naysayers saying it wont happen but knowing Cree , getting Xhp70.2 was only a matter of time and cost.
Now i plan to pop one into a Boss with 4x26650 16v DD on a beefy 50mm thick chunky heatsink to get a whopping ~10k lumens single emitter compact thrower worthy of a flasholic envy. :+1:
This is what i call ‘Pushing on the limits of existing technology’. Doing anything less would be better off going the way of buying a production light.Why bother……
sorry, i dont keep up with the topic
if i change all the XHP70 in my olight X7 to XHP70.2, how many lumens i will gain, and is it worth doing
Nobody has done tests yet.
It will also depend if you’re using a CC or DD driver.
If it’s CC then you will get an efficiency increase and probably very little additional lumens, if it’s DD you will get an efficiency decrease and much higher output.
Link to the driver?
Vinh at Sky Lumen got a batch of these 70.2’s in and has already made a few 20k+ lumen monsters.
Of course it’s CC driver
Currently it’s about 3000 lumen per xhp70, still not the maximum
I think if i change to ver 2, maybe i will reach 10k-11k lumen
Could you help? I m looking for 16 mm DTP mcpcb for xhp70 for 12 V and with isolated thermal pad.
IMO for 12V there is none. However there is one modified 16mm one for 6V only available here XHP70 6V 16mm DTP Copper MCPCB
But I think this process is not possible with the 12V pcb.
12V: http://kaidomain.com/p/S025183.16mm-Dia-x-1_5mm-T-12V-DTP-Copper-MCPCB-for-Cree-XHP70-2pcs
But what do you mean with isolated thermal pad? It is connected to the LED-Base directly.
6V is also aviable: http://kaidomain.com/p/S025182.16mm-Dia-x-1_5mm-T-6V-DTP-Copper-MCPCB-for-Cree-XHP70-2pcs