I have an external battery pack for my camera that is switchable to 12.1V. With a coiled power cord, this would easily supply over 5000mAh for a protected and monitored steady power supply. 
Hmmmm……
I was thinking about direct driving a few of them to upgrade the interior lamp in my car, which currently has an XM-L2 in it at around 2A. I then remembered that a pair of mounted XHPs is worth about 5% of my car's value. I am still going to try a direct drive to see what they'll do!
I have 3 - 12v lithium drill packs that I have found in the recycle bins. Thinking ahead, I have already found an open box deal on the charger for them at $10. I could make up a higher capacity pack and use the BMS board and charger separately to charge the pack. The only question is how well, and how long would 1 or more of these ’70s run in direct drive with pack of 3s1p or 3s2p, etc. (12.6v at the initial full charge state).
I have already powered a big light this way running on an 18v pack.
Well, with an FET Direct Drive driver and the 6V set-up on 8.4V of cells the XHP70 wants a little over 12A, so I would think that in 12V configuration with plenty of cell to push it you should see easily 6A or more. And it will be very very bright! Should be an interesting experiment to say the least.
A reflector with refracted finish works well to blend the 4 dies, such as the Ledil Minnie-W or a Fresnel reflector with it’s diamond like pattern on the finish.
Have fun!
13-14v seems like a bit much for in-car lighting w/ an XHP70. Like DBCstm said… 6A+… djozz’s testing @6v showed ~8.5A at 6.9v (1/2 of 13.8v).
Depending on your goals a cheap CC step-down regulator seems like the safe bet! That will also prevent the characteristic brightening / dimming of your interior lights as the engine revs up and down (or the alternator is disengaged).
You're forgetting about how much voltage the thin wires are going to drop. 
I should have put one of these 
after that because I wasn't seriously considering direct driving one inside my car. The XM-L2 was already so bright that I ended up turning it down!
Emoticons do help carry the sarcasm. 
Personally what I really really feel like I need inside my car is more even lighting. I’ve got the rear dome and the front driver/passenger reading lights. They are stock and don’t put out a lot of light, but the key problem is where they put the light. I suspect that if I had a higher end vehicle I might find a few more nooks and crannies with lights crammed into them illuminating floorboards & etc.
I get what you mean. The reason I put an LED in mine was because the bulb had been burned out for a while and I had a few extra hours to burn on a Friday afternoon. I figured I already had the LED and the buck converter, so why not? 
My car is small enough that the bare LED pretty much floods the whole thing. The obvious downside is that you don't ever want to look directly at it, since you will be seeing spots for a while.
That wasn’t criticism, I wouldn’t mind getting a little more light out of my dome & reading lamps. I was just speculating on what would be ideal.
That would be more ideal. 
I just use a Chinese disc of smds (smaller than 5050s (rectangular)) about 10 or so of them n the centre light, and its bright as hell without killing your eyes. I cant imagine how bright an XML might be in there. I also have floor lights and a light over each side of the rear seat.
If the sinkpad traces were 2oz, .02” wide and 1.5” length in total the resistance would be about 18mΩ. If it’s 3oz then 12mΩ. I haven’t quantified what 18mΩ is yet, so, what would be the consequence of this amount of resistance?
Guessing 18mV drop per Ampere.
Interesting idea. I’ve been doodling and calculating trying to figure out what would be best for a battery operated camping lamp, XHP70’s, MTG2’s or XML’s. With the current 3000 Lumen Coleman propane lamp, the white mantle glows across a large surface area. I suspect the long tube mantle is more tolerable to have on a table in your field of view than the intense point of light of an LED.
The idea of essentially a vertical sleeve of 5050 size SMD LED’s might be nice too. Assuming I could source some 4000 Kelvin 5050 SMD’s…
Sorry, back on topic. How hot are these little buggers when run at, “Full Stupid”? The ER is crazy busy and I’m racking up the OT and contemplating 3 really stupid ideas including a convoy S2. I suspect it will get as hot as my S3 does with the MTG2 when running direct drive, painful. But roughly 3x the output…
I wish I could say it was my idea, theyre readily available on ebay, probably not all that good technically, but they work fine and dont seem to get hot. No idea of tint or bins. I think there are brighter rectangles than the 5050 though.
This is much like it, but its not exactly it I think the LEDs are different from memory, I recall rectangles not 5050s.
One would be reasonably bright over a table, but wouldnt throw much light light beyond it.
I am sure I am not unreachable, I just reached out and touched myself, ok that didnt come out right.
Boys send emails, loving to hook the brothers up
Now where did I put my birth light, its around here somewhere......
Cheers
Mark
Old subject matter thats needs a refresh. The magic is in the die MIDurham, the packaging is MIChina
Cheers
Mark
I'm not sure whats going on here but if I get time the last of the big spenders will be in tomorrow if he gets time for another two XHP70 N4 3C bare leds.
Wherever they’re made, they’re potent little buggers!
3 XHP50’s on 20mm Noctigons in an M6 utilizing a 20mm FET driver (Zener modded) and 8 Efest IMR18350 cells (4P2S) shows 9522 lumens in my lightbox. Ridiculously crazy!
I’ve seen my lightbox go to 12,000 (4000+ lumens) before on the meter, I saw 18,000 (6000+ lumens) with the FET driven XHP70, this light took it to 27,600! I was forced to use the x100 setting, crazy crazy crazy. And the heat coming out the front, well it’s just nuts.
The neat thing about the use of the XHP50 is that it fits right into the centering rings and works physically just like the XM-L2’s that were already in it. I thought about re-flowing them right onto the stock mcpcb, but being aluminum it made me refrain. After 15-20 seconds in Turbo you can shut it off and just sit there and feel the heat flooding into the head and body of the light, with the light off! lol
Coming up next are the 70’s…… gotta do some things differently there for sure.
I have to note that the Turbo level on this light and it’s impending brother is designed as an intruder deterrent in the home. It’s not to be used for any real length of time as flashlights go. It just can’t handle the heat like this. I need to look at a way to make the positive leads captive, to ensure that when they float off the star they can’t short out. As you might can see, the potential for things to go wrong in a light like this is enormous! Not even a question of “if” things go wrong, but “when”.
Where can I get a 6v copper MCPCB for the XHP70? The free samples are the 6/12V ones, and for the reasons mentioned above I’d rather go for the 6V only MCPCB. I’ve emailed SinkPAD, but for them to do an order it requires a larger amount. Anyone know where can I order just one or a few?