You may be right. Now that I think about it the most I have done this with was 3 cells to 3 emitters and I did it slightly different even then.
Doing this it worked.
http://www.candlepowerforums.com/vb/showthread.php?201392-Poorman-Mutli-Lux-setup-method
4 may be a touch too much.
If you are using a zener mod then a 10V capacitor will still work because the zener diode limits the capacitor voltage.
So the normal zener-mod with R200 resistor and the 4.3V 200mW zener diode would be able to work with 4 batteries in series to drive an XHP 35? Using FET driver.
VOB wrote:
RMM wrote:Has anyone ever run 4S into 7135s? If they are even doing minimal regulation they will burn up muy rapido. f=
Also, 7135s are only rated for around 7V output. We get away with 2S cells, but 4S? I guess someone will have to try to find out, but I think you'll probably get some magic smoke.
You may be right. Now that I think about it the most I have done this with was 3 cells to 3 emitters and I did it slightly different even then.
Doing this it worked.
http://www.candlepowerforums.com/vb/showthread.php?201392-Poorman-Mutli-...
4 may be a touch too much.
I don't believe you are subjecting a 7135 to 16.8 volts when you hook up to 4S cells. You have to take into account how much voltage is being used by the emitters. For instance, when you hook up 4S emitters directly to 4S cells, you are not subjecting each emitter to 16.8 volts. Each emitter demands a certain amount of voltage for the current available. Cell voltage sags as current increases an equilibrium is found.
When current is limited by the 7135's, there is less sag. So an excess voltage situation is created. This is the voltage that the 7135's see. The data sheet says voltage limits specified are relative to ground. That is just my theory and not based on anything I have read. So it could be completely wrong.
That makes complete sense. The voltage across each 7135 is going to change as the battery drains, as long as the Vf of the LED is within 7v of the input voltage all should be fine.
PWM is where I start to get hazy, with the driver still putting out short high current bursts to create a lower RMS power, will the 7135’s act like they’re driving an output with a lower Vf, or will the interaction be just like when PWM = 100%, just pulsed?
If it doesn’t act like just a pulsed version of the full output, that could be why they might die in a setup like we’re talking about.
I don't understand that aspect either. I know that 7135's hate heat and they run cooler as lower PWM's. I guess the breaks between on pulses allows them to cool off some.
I really can't picture 7135's dissipating 7 volts though. Even 1 volt gets them real hot. Proper heat sinking is critical.
My bad. RMM was right. Just now I tried this with 4S behind the zener modded 7135 driver + an XHP-70 and it does not work. I was never able to get more than 600ma from the driver, and the modes would not change.
I also tried this with 4 gen 1 XMLs and the poor mans setup and the result is not much better. I was able to get full power but only for a short time and after a bit I was not able to change modes again.
Neither setup killed the driver, but it did get hot very fast. In the XHP-70 test I even had it pressed into a copper slug similar to a C8 pill. Running it like this for long would have killed it I think.
The 7V limitation really only applies to the Vdd pin since the voltage drop from led- to ground is whatever is left after deducting the led Vf. There isn’t a hard ceiling as far as I could find other than above 700mW heat sinking becomes critical to maintain operation. 700mW translates to a drop of 2V. The other fine print item I’ve mentioned before is noting the benefit of up to 1000^2 mm of trace area for heat sinking each chip. Pretty sure there isn’t that much trace area available unless you mount each one on a 12.6mm board with nothing else but copper on each side(pi x 12.6 x 12.6 x 2 = ~1000). Given adequate heat sinking they can be driven much harder but I don’t believe they can share that sink with another heat source unless it is sized for both.
This seems ideally suited for a MTNmax driver set to 2-3A though.
What eventuated out of this?
An ideal LED for a C8 and single 18650?
Or more a realistic option for a TM16 with quad XHP35?
Perhaps the TM16 is more suited to XHP50-70?
I dunno, you lot would, right ?
Well, the XHP35 is a ~12V LED, so you need either a good boost driver or at least 3 Cells.
So, this isn’t a LED for most flashlights, it’s more made for cars and other 12V facilities
i built a xhp50 TM16 
but the mcpcb died - noe i have copper dtp on the way to finish that project sometimes
I know of one light which can possibly benefit from this LED. The XHP35 can do some amazing things, just in rather unconventional situations. The hi-CRI at 5000-6000K is one thing that we often never have access to, but I’ve seen another side to this LED which I am quite interested in.
How many lights currently use a boost that we know of out there?
The TR-S700 is one that does use a boost circuit. It has an amazing hotspot for 7-LEDs. It is also beneficial as the cell count, whether using 1, 2, or 3, doesn’t really effect initial output in the S700. It is just about ready all of the time to get up and go.
Zebralight is selling 1x18650 XHP35 based lights:
SC600 Mk III - now available with XHP35 in both cool and neutral tints.
SC600W Mk3
SC63 - available for preorder in both cool and neutral tints. Supposed to ship at the end of the month.
SC 63w
If Zebralight can get a sufficient supply of emitters they are also thinking of offering the above lights in 90 CRI XHP35. That would be pretty nice: A tiny SC63-sized light with 1100 lumen output of hi-CRI 5000K light.
Thats a sweet light. Thanks for sharing.
The high-CRI Zebralights sound nice, but I worry about whether they’ve finally fixed their tinted lenses and if the emitters still make a Cree rainbow. It could turn out to be a much lower CRI than advertised, depending on details like that.
Now, if they used a dome-less emitter, that would help a lot. And an untinted lens.
Even more amazing is that they accomplished this with a comparatively small boost driver that scales up to 12V or more from a 4.2V cell. I hope they can maintain CC boost regulation down to the claimed 2.7V LVC. Very cool indeed!
MAXTOCH Copper MCPCB Cree XPG
+
XHP35A-00-000-0D0BD40E3
die at 1.8A
4 elements with the 12V supply voltage.
One of the segments extinguished.
Can some one sum this up for me please? i bought a XHP35 and i would love to put in my convoy L2? how does that sound?
You’ll probably have to use 4 18350’s in series to get the voltage to run the emitter. I don’t know of any boost driver to up the voltage of two 26650’s to meet the 12v requirement.