Finally added PCBs (and LEDs:) to webshop:
Luxeon V: link
L4P 4040 DTP 16mm for Luxeon V : link
Note: since I'm on vacation until next Friday, orders will be processed and shipped after 13th October.
:+1: :+1: :+1:
Wouldn’t this LED be a good choice for FET driven 3x AA lights (e. g. Convoy X3, powered by Eneloop cells)?
That is a good price for the DTP board for a Luxeon V.
I got my led4power 4040 boards in (thanks!) and did test the Luxeon V on this dedicated board, I will try to crush the numbers this weekend and post the result. In short: I found hardly a performance gain (very slightly though), but the ease of reflow makes this board well worth using. I expect the reliability to be higher as well.
I did one not so great mod with the Luxeon V, I put one in a Olight S15 (AA) flashlight and hoped that the low Vf, and thus less voltage difference to boost, would increase the current and output compared to the stock XM-L2. But it is apparently not that simple, instead, I found just 180 lumen with the Luxeon V, compared to the ~250 lumen of the stock XM-L2. It must be something measured different in the electronics that makes it get less current.
The VG10 with the direct driver and Luxeon V is still one h*ll of a light, great beam, great tint and with a half-drained 30Q it still puts out 1700 lumen (at still 6.5A current, 75lm/W flashlight efficiency).
Edit: some numbers corrected and added
With these leds available for well over a month (now at RS-online as well), are there more experiences out there using these in flashlights?
I found a similar effect with putting red 660nm and yellow 585nm LEDs in SF-348 lights.
They get less warm too.
Apparently there’s things about boost drivers that are counter-intuitive.
Isn’t it that the driver is just constant current and the only benefit from low Vf is longer regulation and (if present) higher efficiency?
At least that would be some crazy efficient 180 lumens. Will be placing an order for the boards and emitters soon.
I’m not totally impressed by the efficiency, I measure 2.4A at the tail, an Eneloop runs at 2.4A at around 1.25V, so that is 3W of power and thus 60lm/W. For a light that needs boosting from a NiMh cell that may be alright actually, but at least some of my flashlights with li-ion cells go over 100lm/W.
That is disappointing, wonder if that is down to the boost driver or the emitter. What does the XM-L2 pull from the tail?
Never measured that, this is already the third emitter in this light.
Anyone with a stock S15+clamp meter+thick copper loop?
After reading this I would like to repeat my question:
“Wouldn’t this LED be a good choice for FET driven 3x AA lights (e. g. Convoy X3, powered by Eneloop cells)?”
I am thinking of a bright flashlight with NiMh cells for my son.
I guess that’s not so good, as the low Vf leads into pretty high current for NiMh on DD drivers
for a regulated driver this LED is good
Would be great for something like the Sofirn SF11 or Lumintop SD4A which are 4xAA lights with a buck driver. Should give nice long runtime.
According to HKJs’ review Eneloop 1900 mAh delivers a current of 5A at 1.1 V, which (with 3 cells in series = 3.3V ) meets djozzs’ numbers pretty well (5A at 3.25 V for 1800 lumens).
Yeah but you loose quite a lot voltage and the efficiency goes down
5A is a lot from AA NiMh
Where do I lose voltage? 3 cells in series sum up to about 3.3V at 5 amps, where the LED is pretty efficient. Eneloops should be good for this current, HKJ tested them up to 10 amps with a max. temperature raise of about 20 °C. Even the capacity of the cell doesn’t decrease much at higher currents.
Coincidentally I was able to do a quick check on 3 Eneloops in series because a few years ago I made a 3xAA carrier with phosfor-bronze springs and Omten switch (using Oshpark boards) for a project that I never finished. Pushed against the Luxeon V-modded VG-10 head I checked the output on 3 fully charged Eneloops, 30 seconds after switch-on I measured 1400 OTF lumen, that is about 1600 led-lumen, which should be about 4.2 amps (measuring the amps directly is not as quick as this was).
Of course upon draining the batteries the output goes down considerably (though not dramatically because the voltage curve of the Luxeon V is relatively steep), but this at least shows that a 3xNiMh set-up should work well enough to make a flashlight with very decent output.
Thanks, djozz, that’s close to what I expected. Looking forward to my X3 mod once the LEDs arrive …