Tested CNQ Boost driver (Luxeon Triple in series)

Flashlight Modding and DIY Parts
1

Hi,

I’ve been looking for a boost driver for driving a Luxeon triple/3up in series from 1 or 2 Li-Ion batteries. The reason for wanting to drive the 3 emitters is series is because the 3ups I got are configured that way by default, and also, I don’t want to jumper the emitters in parallel or run 3 pairs of wires from the driver to the 3up.

Earlier, I had tried some boost drivers from FT (their 800mA and 1000mA drivers), but even though they’re boost drivers, their output voltage was limited (in series, the 3up requires ~9V at 1000mA), so that didn’t work.

So, I recently found and ordered a couple of these drivers from CNQ:

http://www.cnqualitygoods.com/goods.php?id=1391

and, I received them today.

I setup an impromptu test jig, and it appears that they do work. Initially, I used 2x14250 batteries from Lighthound to power the driver, and using a clamp meter, I am measuring at the emitter:

Batteries: 2x14250:

  • High: 1000mA - ~9.11V
  • Low: 340mA

I also tested with a single 18650:

Battery: 1x18650:

  • High: 660mA - ~8.65V
  • Low: 240mA

Note that this driver also has a strobe mode. I don’t mind that, but I know some people would, so I figured I’d mention it.

Now that I have a suitable driver for the 3up, performance-wise, I just have to figure out how to squeeze this driver into one of the $2.99 S5s that I got from Ebay :). I’m planning on using 2x18350 or 2x16340 for power, since the S5 is designed as an 18650 light.

Edit: Updated above with voltage and testing with 1x18650. I was kind of surprised that it worked with 1 Li-Ion, because CNQ’s website specifies 2x18650.

2

Good info. Thank you. Does that driver have good memory (not next mode memory)?

3

I’ve just been using some alligator clips for the switch so it’s hard to tell (since I sometimes “double click” by accident), but I’ll hook up a real tailcap switch and check that in a bit.

4

Just checked, and it looks like next mode memory, so it’s the “bad” memory (for you)…

5

One thing I forgot to mention that may not be obvious from the pics on CNQ.

The contact board (the larger board) doesn’t have the usual negative ring around the edge on the battery side. Rather there’re two spots of solder on opposing sides of the board facing the battery side, and those are the only negative contacts as far as I could see.

In my case, the light I’m putting this in has a retaining ring that’ll clamp down on the battery side of the contact board, and those two solder spots will provide the negative continuity, but if the light you use them in doesn’t have such a retaining ring, you’ll need to bridge the two points to the pill probably.

6

I had PM’ed RIC with some questions on more detailed specs this driver, but he hasn’t responded, so I did some more testing with it today with it and a 6V MT-G2 emitter using my bench supply.

It does seem to be able to driver the MT-G2, albeit with low emitter current, up until a certain voltage.

When I increased the input voltage on the power supply to > ~6.8V, my power supply goes into “CC” (constant current) mode, and after that, I can increase current on the power supply (and voltage increases correspondingly), and it seems like at >~6.8v input this driver goes into direct drive?

However, regardless of input voltage, with the MT-G2 hooked up, I lose the normal modes (L - H - Strobe).

The driver appears to have survived, as when I move the emitter leads back to my test Luxeon triple, I get the modes back, and it behaves I described in the OP.

So, would it be accurate that this is a boost driver, but it seems like when the input voltage is greater than the emitter(s) Vf, this drive goes into DD?

Also, why would I lose the modes when the MT-G2 is hooked up to it, why would I be losing the modes (again, apparently regardless of input voltage)?

7

I don't know the answer to your question. Maybe the modes disappear because the MCU gets overwhelmed by the higher voltage?

8

Thanks…

The driver is spec’ed for 2x18650, so that shouldn’t be a problem, plus it does work with, say 8V input with the Luxeon triple - but not with 8V input and with the MT-G2. I’m wondering if maybe the MT-G2 is taking too much current, and so the driver doesn’t get enough current to work properly?

Kind of strange.

9

Yes, a lot of boost-only (not boost-buck) drivers revert to direct drive when Vin is greater than Vout. Too bad there isn't a boost driver that will run a MTG2 at reasonable current from a 3-4.5v input. :(

10

Taskled?

11

Yes, they do make drivers. What about them?

12

Thanks Ohaya. I was shopping at CNQG today and picked up one of your drivers…just in case.