LuxV driver?

Hi All,

I think I know the answer, but what are my options for driving a low Vf LuxV (WYOS) at about 400ma in a sammie-sized pill? This will be going into a CNC-123 w/ a protected R123.

I know a BB400 could work, but I had a BB500 VYOT light die on me for no apparent reason so BB's and LuxV worry me a bit.

Any other options?

Jon

Anyone?


I looked up the specs on the MicroPuck. Two of them driving a single LuxV will yield about 400ma at the voltage I'm shooting for, but only one will fit into a sandwich/pill sized area.

Jon

If you have room (0.8" diameter) Fatman will happily drive a LuxV from a li-ion cell at up to 1A if the li-ion can supply the input current. With an R123 you will be limited by its capability to supply current.

Since you're after a boost converter, input current will be > output current due to input voltage < output voltage.

george.

I just built a BB400/WX1S LE for my Aleph. I thought the Badboys were the only option in the size range. If there are more boards that would fit, I would also be interested.

georges80 - Thanks, but unfortnately a .8" diameter board won't work. I might be able to hog out the CNC-123 a bit, but I doubt it.

mateen - How much time have you put through the WX1S/BB400 so far, and are you using an R123 or a 17500? As I said, my BB500, 2x123, VWOS(??) light died after just a couple of hours. It would, at times, not light up or act as if the batteries were almost dead. Opening up the light and/or switching batteries seemed to fix it, but it finally gave up the ghost. The reason is still unknown (probably my fault though).

Jon

Actually, due to my OWN worries about LiIon and Badboys, I have only run it on primary CR123s so far, to the tune of around ten hours I would guess. I have only used primaries in order to have some limit on the maximum current going through that board in its efforts to boost 2.7 - 3V up to 6V. I remember reading somewhere that since the LiIons can give up so much more current the Badboy will fry itself if given the chance, IIRC. I think that was just one theory though relating to LuxV LEs, Badboys, and LiIons.

Your BB500/VW0S was running on 2x123 primaries and it gave up?

What's the diameter you're looking for? I believe I can design this driver. I already have one designed that draws 1.8 amps from a AA li-ion and drives the lux V at 5 watts. It sounds like you want about 3 watts, I think that might be do-able, I just need to experiment a little. Check out my ad in B/S/T, I will do this service for $22.00.
I'm trying hard to build my reputation here at CPF, but it seems to be a tough crowd sometimes.

How much time have you put through the WX1S/BB400 so far, and are you using an R123 or a 17500? As I said, my BB500, 2x123, VWOS(??) light died after just a couple of hours.

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I'm sort of in a long-term process of putting together several LuxV Alephs. When I was first researching this, I found several reports of BB drivers failing with "S" Vf LuxVs. This makes sense to me - the BB just doesn't like at all for Vin to be higher than the Vf of the LED. My fresh primaries measure 3.2V - that's conceivably .5V higher than the Vf of an "S" Vf LED. In the same situation with a LuxIII and NG driver, it's not nearly so tricky. LuxVs are tough

My first two LEs were a BB500 WXIS and a BB750 WX1T. The "T" bin I didn't worry about on primaries. For the "S" bin, I burned in the cells for a minute to get the voltage down, and never had a problem.

That "S" bin is now on a 18650 and hasn't been a problem.

Bob_G said:

I'm sort of in a long-term process of putting together several LuxV Alephs. When I was first researching this, I found several reports of BB drivers failing with "S" Vf LuxVs. This makes sense to me - the BB just doesn't like at all for Vin to be higher than the Vf of the LED. My fresh primaries measure 3.2V - that's conceivably .5V higher than the Vf of an "S" Vf LED. In the same situation with a LuxIII and NG driver, it's not nearly so tricky. LuxVs are tough

My first two LEs were a BB500 WXIS and a BB750 WX1T. The "T" bin I didn't worry about on primaries. For the "S" bin, I burned in the cells for a minute to get the voltage down, and never had a problem.

That "S" bin is now on a 18650 and hasn't been a problem.

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A good driver would just go into direct drive if the Vin was too high. Without a constant current driver a trim-pot should be used unless wide-open operation suits the use.

A good driver would just go into direct drive if the Vin was too high.

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The BB is quite an old driver by CPF standards. The NG (Next Generation BB) does go into DD, with a .7V tolerance I think, but the BB is the only boost driver Wayne has that will handle the LuxV. It's certainly problematic, but that's what we're stuck with.

I know there are other drivers out there that will handle the LuxV, but I don't know if they'll fit the Aleph LE (need to be ~.55"), or what other considerations there are for using them.

Bob_G said:

I know there are other drivers out there that will handle the LuxV, but I don't know if they'll fit the Aleph LE (need to be ~.55"), or what other considerations there are for using them.

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Maybe I can help. Are wanting to regulate 2 Li-ions for a Lux V? Or boost 1 li-ion?

Bob G,

Unless I've forgotten something, I don't think that there's anyway that you'll find yourself in a situation where the Vin will exceed the Vf of any Lux V when using a single li-ion cell (3.7v) as a power source. Even the lowest Vf Lux V needs a boost converter to run on a 6v power supply.

Stonedog,

I had a light sent to me a while back that was exhibiting the same sypmtoms as you have described. After tearing it apart, I found that the ground path had been broken some place. I was easier and cheaper to just replace the converter, so that's what I did, but I'm sure that it could have been repaired, if I was inclined to spend the time.

I've heard a few stories about Badboys dying when driving a lux V with a li-ion cell, although I've built quite a few and never had any problems.

In any case, driving a Lux V with a single li-ion cell is really asking alot of the converter. An S Vf Lux V has a Vf of anywhere between about 5.9 to 6.4v. You're really asking alot of the converter when it has to boost voltage by two full volts (at least) and supply the current that most of us want to drive through a Lux V.

Since the BadBoy does not have a current limiter built in, it will simply work itself (apparently to death in some cases) to boost the voltage to attain the desired current.

All I can say is that to play it as safe as you can, use a Lux V with the lowest Vf possible (probably an S) and drive it moderately.

MillersMods,

Yeah, breaking in is kinda tough to do. Alot of the lights being built here are the products of blood, sweat, and tears and many are apprehensive about putting something unproven into something that they are making a financial and personal investment in.

If you're taking orders, I'd be interested in a converter about 1/2" in diameter that will do two levels of light in regulation that will allow the use of an easily incorporated switch to go from one level to the other. Maybe even something that would work with a twistie light. Buck, boost, or buck/boost, whatever. You come up with something and I'll build a light around it. I guess I'd prefer a boost coverter. I like doing small lights and I just got some McR16 reflectors and lenses to fit them and they're looking for a home. I'm sure that I could put something together in a couple of days, once my lathe and mill are back up and running.

Once the light is built, we could do a torture test of some sort on it.

I suppose that I'm just looking for something to do.

Tony,

Unless I've forgotten something, I don't think that there's anyway that you'll find yourself in a situation where the Vin will exceed the Vf of any Lux V when using a single li-ion cell (3.7v) as a power source. Even the lowest Vf Lux V needs a boost converter to run on a 6v power supply.

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I'm not sure what you're referring to here - as I read StoneDog, he was running an "S" Vf LuxV in a 2x123 setup when it failed. For myself, what you say is why my low Vf BB LuxVs are on Li-Ions now (18650s thanks to TBase)

Maybe I can help. Are wanting to regulate 2 Li-ions for a Lux V? Or boost 1 li-ion?

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What I will want is to boost a single Li-Ion (18650 protected) to drive an S Vf LuxV at 600mA. If it could also safely run 2x123 primary with the same LED, in other words run DD if necessary until Vin fell, that would be pretty interesting.

I don't know enough to know what the issues are however. One would be how the driver reacts to a resistored low, which Alephs have (30-45ohm in this case.)

Like Tony said, the BB isn't current limited, and it puts out a LOT of heat, and that's kind of annoying. I don't know if it's less efficient in low because of this, but I've always suspected so, but like I said, over my head.

If you've got any ideas, I'll be glad to listen.

I'm sorry. My appreciation of Stonedog's concern was that he wanted to run a Lux V on a li-ion cell, but was apprehensive about using a badboy because he just had one die. I assumed that he was running it on a li-ion cell, because the issue of running a badboy/lux V combo on a li-ion cell was a subject of some discussion here a while back.

In any case, as I said, I'm not aware of any situation where the Vin would exceed the Vf of the Lux V, whether it is on a single li-ion cell or 2X123. Considering that the bottom end of the S Vf range is 5.91v and given a situation where you actually have a Lux V with an actual Vf of 5.91v, the voltage drop of the batteries under load and the overhead of the converter would all but insure that the Vf of the Lux V would not be exceeded by the Vin.

If Stonedog was indeed running his light on 2X123 when it failed, then the Lux V/Li-ion issue doesn't apply. I can whole heartedly say that the failure was either due to a bad solder joint (it can happen to anyone), or the converter just failed and the failure was an aberration. I've built over 100 lights using the badboy converter and IIRC, I haven't gotten a single one back because the converter went bad.

If an alternative is still being sought, Georges80 might have something for you too. He also builds very nice converters, although they are a bit larger and I haven't been able to successfully incorporate one into a light engine.

As for your successfully running a Lux V/Badboy setup on li-ion cells, many here have been doing it for a long time, myself included. Unless I'm mistaken, a lot of it started when we were looking for a cheap way to run our L4s, which also incorporates a boost converter, not unlike the badboy. The Surefire circuit gets hot enough to cook on when driving the light with a li-ion cell.

All in all, I guess it's safe to say the badboy has some issues It's very frustrating for me, because I really like the LuxV, and although it runs beautifully on a DB, it's nice to have something a bit smaller as well. So far I'm very pleased running three of them off of 18650s. I don't know what cells were causing problems in the past, don't recall reading anything. I'm wondering if the mAh rating would have anything to do with it - in other words, would a R123 be more likely to cause problems with a BB than a 17670 or 186560, all else being equal. So much of this stuff is anecdotal it's hard to get a clear picture of when there are real issues vs. bad luck or maybe even user abuse. One thing for sure I guess is that the BB gets hot no matter what it seems

Chop said:

I like doing small lights and I just got some McR16 reflectors and lenses to fit them and they're looking for a home.

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i built a Inova X1, TWOH, MM+ wideopen,
i wanted to go with the McR-16 but went with a IMS 17 cause i
could turn it down to 15mm with my dremel..
with your tools and skill you could bored the bezel/head and drop in the McR-16....

mateen said:

Actually, due to my OWN worries about LiIon and Badboys, I have only run it on primary CR123s so far, to the tune of around ten hours I would guess. I have only used primaries in order to have some limit on the maximum current going through that board in its efforts to boost 2.7 - 3V up to 6V. I remember reading somewhere that since the LiIons can give up so much more current the Badboy will fry itself if given the chance, IIRC. I think that was just one theory though relating to LuxV LEs, Badboys, and LiIons.

Your BB500/VW0S was running on 2x123 primaries and it gave up?

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Interesting theory. As far as the primary CR123, does it stay in regulation very long, and do you know if the full 400ma is making it to the LuxV?

Yes, my BB500 combo died and I'm not sure why. Heat may have been a concern (it died in Florida mid-summer in a high heat/humidity environment). It was installed into a PR-T/ecan combo running on a SF E2e. Sweet little light, but after riding in the pocket for a while it would act as if its batteries were dead. Sometimes opening up the light and/or replacing the batteries would revive it. Finally it just flat out died. Not sure why, I didn't do anything very scientific to trouble shoot. Ended up replacing hte driver with a DB500 and ran it on 2xR123 and/or 3x123.

Jon

MillerMods, Hang in there. Build some good drivers and try to get some folks to post positive reviews. It will come, don't worry.

As for what I need, I want a driver that is one-sided (if possible) and about .5" in diameter. This is going into a CNC-123 which takes Mini-Mag sandwiches and pills, so it has to fit into a mini-mag. Anyway, I'd like about 400ma to the LuxV from a single protected R123 Li-Ion. I don't know what the max current is for a typical R123, but I bet the protection circuit kicks in well before 2C? 1.2a would be the max draw I think. I haven't done the math to see if this is even theoretically possible. But, I want what I want!

Chop, My BB500/VWOS issue may very well have been related to poor ground path. Now that I think about it I had issues getting the BB's ground lead soldered to the e-can. Shoot - if that's what it was I'm going to be very mad at myself. That was a neat light! For my ego's sake, I'll throw out the possibility that new batteries that were physically warm (100F, and therefore a lower internal resistance?) coupled with the low Vf and mild drive may have put Vin over Vf? Either way it's good to hear that you haven't seen any issues with li-ions powering BB/LuxV lights.

Jon