That 22mm driver will work, you can simply not use the highest mode until the battery voltage drops or have RMM set the max pwm in turbo to say ~200 to limit current. It depends on how much self control you have.
So I was thinking about these new generation LEDs with FET drivers. If the MCU is monitoring cell voltage with an ADC for LVP, would it be possible to reprogram the MCU to use the value it reads to limit the PWM until cell voltage falls?
Ex. If it sees the cell voltage is at 8V, only command a maximum of 75% PWM or something, then when the cells are down at 7V let it get to 90%, etc.
If that does work it should let us take advantage of the efficiency increase of the new emitters as well, which linear does not.
I was able to borrow a clamp meter to measure amps on my L6 with 50.2. I used a 10ga wire (too big?) on the tail end.
With the Liitokalas 8.9 amp.
With the KeepPowers 6.7 amp.
So no giant 12 amp loads, but that is a big difference just between batteries.
Compared to my xhp70 with same driver (rough estimates until I put the xhp70 back in)
Liitokala 8.0 amp
KeepPowers 6.4 amp
Hey Jason,
I am planning on making a very similar build, with a mt-12 body (similar to F-13), a mt-g2, and a pair of 26350 batteries.
I’m planning on using this driver:
http://kaidomain.com/p/S025265.New-FX6-22mm-6V-8_4V-5A-2-Groups-of-3-to-5-Mode-Driver-Circuit-Board-for-Cree-XHP50-XHP70-MT-G2
Well that’s if it ever gets here, kaidoman took 21 days to ship it out.
Supposedly the driver is regulated with a high of 4500ma, I’ll see how it performs if it ever gets here.
In theory it should provide a nice regulated output for the new low vf emitters.
Thanks, I’ll make a note of it. Richard at MTN has me covered, though. This one.
6 amps is no slouch and I can remove 7135 chips if I want to bring it down some for better battery life and less heat build up. The best thing is I can have Guppydrv with off time memory and it’s user setable turbo timer. :+1:
Anyone have an idea?
Some speculation... They are binned the same, so same amps = same lumens. For the lumens output issue, depends on the driver, whether it's more amps limited or total power (watts) limited. The lower voltage of the 50.2 could be a good thing (more lumens output) or potentially bad thing - might have to burn off more voltage, so more heat. For the beam/tint, of course depends on what you are going from/to. The 50.2's don't have the same tendency to black hole the hot spot, but they do tend to yellow around the hot spot. Generally these new design LED's don't throw as well as the old ones - I know the XPL2's don't throw as well as the XPL's running at the same amps.
I'm not familiar with the EA81 or it's driver, so again, can't get specific.Those that know details on buck and boost drivers and worked with the 50.2 could probably answer better than me. Few trade-offs.
Yes, this is possible and something I have been wanting to get worked into Bistro from awhile now.
Although at this point I think we might end up skipping that rather crude method and going to something better unless someone gets it implemented before we make the move to the newer MCU’s.
I just finished up a build this past weekend; an XHP50.2 J4 3A 5000k in a single 26650 tube, using a H1-A booster driver all from KD. It has a much nicer hotspot with no X in it vs the original 50; the corona tint shift is still there like the XPL2s I’ve built, but doesn’t seem as pronounced. Compared to an L2 with a MT-G2 direct driven I built, the max on this 50.2 light boosted to 6v seems around 2500 lumens, or about 50% power on my MT-G2 L2. I don’t have a light meter to check the lumens or candela though.
as texas Ace said the max. Setting of the driver can be limited in the firmware
instead DD a 80% or so cycle as max. setting can be set in the firmware on your TA driver
Can an expert do this please?
Thanks
Low Vf on a DD driver with FET
higher current might blow the LED because it can get too much
on a linear driver like 7135
more heat on the driver less on the LED
on a Buck/Boost driver
less power consumption of the lioght, more runtime, less heat
I got some LiitoKala 26650’s in yesterday and charged a pair up, tested them against the Basen’s in my DBC-05 Triple 50.2. The new cell gave more amperage at the tail end but less actual lumens. Weird when I see that. “Only” 10,833 lumens pulling 22.44A on the LiitoKala’s.
TomE is being an outstanding guy and sending me his pair of Sanyo NCR20700A to test in this light against the other contenders. It’ll be interesting to see how they compare…
Lexel, is the below correct?
This can be controlled through carefully battery selection or programming the driver to run at a lower duty cycle on the highest level.
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Emitter will see same amp draw as a non-low Vf emitter.
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You get the same amp draw to the emitter, just with better efficiency.
this is correct
I want to ask if someone tested the nano MCPCBs from fasttech (https://www.fasttech.com/products/1609/10031707/7156107)? What i can find on the net if i search for nano MCPCB sounds promising (http://www.camnano.com/nanotherm-lc/?gclid=CMuynYPo2NMCFaoK0wodHMUOzw) but i do not know if the pcbs are from this supplier or have the same specs.
Noctigon or SinkPAD XM-L mcpcbs, tried and true.
The issue with LED lights is more about heat then anything. We are pretty much always heat limited and it appears that you would be as well in those lights.
They should handle 1.5A @ 6V fine (about 10W of power) fine from how those lights appear to be made.
You can drive these LED’s up to 10A+ if you can keep them cool and they will make ~5000 lumens each at that level if you do.
Although I am not sure what you mean by 100% efficiency. There is no such thing with LED’s. If you mean the max efficiency then you would only want to run them at like 100ma. efficiency drops as power goes up, see some of the tests we have posted on here for examples.
They will still be pretty efficient up until around ~6A though, so that is not a problem in your case, the issue is once again keeping the heat in check.
That link is just advertising. There are no actual details or specs on it from which to derive any useful data.
It appears they use a DTP copper mcpcb which is great but also no different then any other copper DTP mcpcb on the market. Also they say 100% power, not efficiency. Big difference. 100% rated power for the xhp50 from cree is like 2.8A. There is no such thing as 100% efficiency as the lower you driver it, the more efficient it will be.
We run the xhp50 up to 8-10A in flashlights but that will quickly overheat in that light you have. 1.5A should be about right I figure.
You can run the LED in 12V mode but better off in 6V mode, that will ensure it stays in regulation and that you can use a cheap XM-L DTP copper star.
Are those lights you linked to already LED? It might be easier to either just swap the LED’s in them or mod the driver for a bit more power. Got a link to those lights?
Hi stormrider88, Welcome to BLF!!
The BD "Mad Scientist" guy sure is funny. Talks like he discovered or invented copper for LED thermal management, something we've known and practiced for years. Also several of the major LED high performance flashlight manufacturers have been doing copper for years as well, like Fenix and ThruNite.
That BD site though says 100% power, not 100% efficiency. I think that's mis-leading what's goin on there.
It's a shame because he's dis'ing a lot of us out there, including Richard at MtnE who sells light bars here: http://www.mtnlitebar.com/, who I'm sure is using copper in the LED MCPCB's.
The "Thermal Gap Pad" thing is interesting though. Wonder how efficient that is...
Edit: Ooops cross posted with TA.
+1 with TA!