REGULATED PM6 challenge

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brightnorm

Flashaholic
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Oct 13, 2001
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Am I the only Flashaholic who sees this as a desirable development, who regretfully but realistically observes the inevitable dimming of light as long as the tailswitch is pressed? I am not talking of an incandescent-only A2 equivalent, chugging along at a respectable 50 lumens for 40-50 minutes. Rather, a full power PM6 maintaining its impressive beam for a finite period. I would happily settle for a 30 minute steady burn.

Is this a hopeless quest?

Brightnorm

Note to Moderators: I've posted this here because of its greater traffic. Move it if you must
 
Hello Brightnorm,

I agree. This would be a very desirable development.

Having grown up with carbon and alkaline battery powered lights that very noticeably dim down over time, I have welcomed the new battery chemistries. NiCd, NiMh, and Lithium batteries allow more constant light, but still dim down over time. The TigerLight is a good example of this.

The A2 is a step in the right direction, but can you imagine a constant 100+ lumen output light? Who knows, maybe LED's will have to rise to the occasion.

Tom
 
It seems to be uninteresting to CPF, almost a non-issue. LEDS may be the future but right now incandescents are still the throw champs.

BN
 
Willie Hunt makes some smaller round LVRs with the 10A FET that aren't shown on his website. You might email him to inquire about them. I'm certain one of those could be used to do a nice mod.

I've been wanting to do something similar, and have gathered most of the needed components to put an LVR in a G2 with batt extension running from 3 x 123's. One of these days maybe I'll finish it...

The following are probably the two most important points in creating an optimized design:

1. Battery voltage MUST be higher than lamp voltage.

2. In order to acheive proper lamp drive voltage (and good color temperature), pick a programmed output voltage that compensates for ALL resistances (voltage drop) between the LVR output and lamp. For example, a P60 lamp is rated at 5.5 volts normal drive, but this does not include the LA module spring resistances or spring-to-whatever connections. Otherwise, you might end up with a yellowish under-driven lamp (yuck!)

As for run time -
1)Divide lamp wattage by the number of cells used to obtain watts-per-cell
2)Look at the 123 data graphs to get watt-hours at that power level
3)Divide watt-hour figure by watts for (1) cell. This should get you a close estimate because the watt-hour capability of a 123 decreases sharply with increasing power demand.

Good luck with your endeavor - I hope this has been useful info.

John
 
There is currently a regulated 200+ lumen light: the MR-X. /ubbthreads/images/graemlins/bowdown.gif /ubbthreads/images/graemlins/bowdown.gif /ubbthreads/images/graemlins/thumbsup.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/tongue.gif
 
That's a big light, not very pocketable. /ubbthreads/images/graemlins/smile.gif Of cos there are always some exceptional CPFers who will get bigger cargo pants to EDC their MR-X /ubbthreads/images/graemlins/grin.gif
 
I'm missing the point here. The class of lights discussed here are considered "tactical", a much mis-used word, but one I will take to mean police/self defense/handgun carry. Not just a "walk in the park" kind of light. No white wall stuff.

If my supposition is anywhere in the ball park, a sudden DROP from regulation would be disasterous in most of the above scenerios.

The lithium lights go "out" suddenly enough now, that it bothers me. Enough that I always carry a spare for backup.

Comments ?

I do not mean to cast dispersion against any one wanting a great play light, if it were, but these are lights used for serious purposes.
 
[ QUOTE ]
Illuminated said:
...Good luck with your endeavor - I hope this has been useful info.

John

[/ QUOTE ]
Very helpful John, thank you!



[ QUOTE ]
JohnK said:
I'm missing the point here. The class of lights discussed here are considered "tactical", a much mis-used word...

[/ QUOTE ]
JohnK, I agree. I would not recommend these for professional use; they would be for enjoyment along with a degree of practical use.

Brightnorm
 
"1. Battery voltage MUST be higher than lamp voltage."

Ummm... why? Power can be boosted as well as bucked. In fact, bucking the voltage means you are giving up some light for the sake of regulation.

however...

"a sudden DROP from regulation would be disasterous..."

That would happen with a boost type circuit. If a buck regulator was being used, then the drop out of regulation should not result in a sudden drop in light.

I guess there are arguments both ways. For "Tactical" use a buck type would be safer. Note that you are not getting maximum brightness, since you are regulating power down for the sake of consistant, even output. But there would only be a slight drop in output as the light fell out of regulation, then a gradual dimming typical of unregulated lights.

For smaller size and maximum brightness, a boost type converter would be best. You would get shorter total run time, but longer maximum brightness run time, then <poof> lights out. And LED/Incan combo would work well here. Instead of the incan dropping off to nearly nothing all of the sudden, it could switch from incan to LEDs when the incan would normally fall out of regulation.

Food for thought...

Aloha, iG
 
Is there a 3cell lamp that would fit in the m6?

If not maybe the tps61030 boost could be used with the 2cell lamp, it has a 5.5v limit on output and input as far as i remember. Which I believe will be brighter than direct drive. If it works. I'll look into that, I like the idea.
 
Please allow me to clarify...

My comments were referring to the use of Willie Hunt's LVR for incans. In crude terms, they are sort of a variable duty cycle "chopper" and thus regulate the RMS voltage to the filament. This is why they need a higher battery voltage than the lamp voltage, and also why they won't work for LED's (LED will see full batt volts during "on" pulse state).

FWIW - the LVR does not not run regulated end then die without warning, but it might not be best suited for tactical use due to the slow startup feature incorporated to prolong lamp service life. BUT - for just about anything other than tactical use, I'd much rather have the regulation and features of the LVR than not.

Willie has provided an ingenius method of advance low battery warning by alternately dimming the output just slightly at about a 1 hz rate. The light is still quite usable in this state, and does not require periodically monitoring some indicator for battery condition. Also, the warning flash can be disabled if desired.

The run time following low-batt warning depends on what voltage level you want the warning to ocurr at. For the LVR3C, it will be pre-programmed to something like 0.9 volts above the lamp voltage. For the fully custom units, you can choose the depth of warning flash, warning voltage level, and optionally the low-batt cut-off point (if using rechargeables) to protect the batteries.

I built a bicycle light using the LVR3I, and I have to say that Willie's LVR is *very, very* nice for that application. Makes me want a flashlight with similar features...

Have fun - John
 
Yeah, I want a MAG 2D with 8AA and a LVR with WA1160. If it's too big, maybe any Surefire 3 cell light with turbohead. Well, is there room to fit in a Willie's LVR?

I hate the dimming light. Hope someone will came up with a good solution. I have been waiting for a good one.

Henry
 
Henry,

The LVR3I will handle up to 10 amps, so the WA 1160 or even the WA1274 and likely some others (SL35X) are easily doable. I gutted a Mag 2C switch and sandwiched the LVR3I between the Mag's switch body halves for my bike light project. This worked out very nicely, though I wired it to an external power cord instead of using an internal battery config.

I'm considering the WA1160 @ 6 volts with 6 x 1/2D in my 4D Mag with a Carley 2" textured reflector. Should yield about 40-45 minutes in regulation.

Brightnorm,

Back to your topic - Willie did tell me that he does make a few round LVR units with the 10A FET for (as he put it) "tinkering", and it's something like 0.78" diameter IIRC. That might lend itself well to being modded into a 2 or 3 cell 123 powered light.

I'm thinking that 2 x 123 an an LVR driving a Pila 3.7V lamp assembly, for example might be doable in the right host. I don't have a PM6, so I can only speculate on using it as a host. I'd love to see someone build something like that...

John
 
Maybe we can start a feeler for LVR group buy. Willie may consider a group discount if volume is big enough...
 
What about choice of bulb? Remember that the LVR works on chopping voltage... Are we going to use a Pila 3.7 volts LA? That would mean loosing significant amount of throw?
 
From what I have seen the lower voltage bulbs are significantly less efficient. Some of WA's bulbs in the range between 6 and 12v put out more than 25 lumen per watt.
 
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