Sold/Expired Sold Out hi/low spring assembly for ARC LS

I was selling hi/low spring assemblies for ARC LS and similar lights.


The demand died down so I tore down the assembly line.

You can make your own using information from this thread

Daniel

Re: FS: hi/low spring assembly for ARC LS (NEW)

Great! /ubbthreads/images/graemlins/buttrock.gif
Please consider one sold for me, if only those guys at paypal would hurry up with my account! Should be ready in 1-2 days.

Re: FS: hi/low spring assembly for ARC LS (NEW)

gadget lover, see PM

Bill

Re: FS: hi/low spring assembly for ARC LS (NEW)

I need one, 10 ohm. PM send.

Re: FS: hi/low spring assembly for ARC LS (NEW)

Finally my paypal account is ready. PM sent.

Re: FS: hi/low spring assembly for ARC LS (NEW)

Gadget_lover,

Will this mod work on the new Pelican M6 LED? One is on its way, and High sounds it'll be great, but I want Low too!

Also, I'd like to be clearer on the design principle. Is this simply a resistor running in series with the batteries, so that on Low the resistor dissipates a large fraction of the power (but still with a lot less net power than on High)? If so, I guess it will work with any direct-drive or voltage-regulated setup, but not with current-regulated ones? (Assuming the thing fits the tailcap at all, obviously.)

First post, please forgive any faux pas.

Thanks,
Inluxication

Re: FS: hi/low spring assembly for ARC LS (NEW)

Hi Inlux. Welcome to the forum.

I'm not sure how the concept will work with the M6 LED. Yes, the resistor does go in series with the battery. I've done the same thing (different implementation, but same idea) with a Streamlight TL-3 LED (5 watt direct drive???) and it works there too.

I use low ampherage (30 to 60 ma) so the resistor does not have to be physically large.

There's a thread where I described the whole concept, complete with parts list and instructions. click here

If the PM6 has a replaceable spring you should be able to do something to make it work. It does work on converters that drop back to direct drive when the batt voltage falls below a set point.

Daniel

Re: FS: hi/low spring assembly for ARC LS (NEW)

Gadget_lover,

Thanks for the quick response. Someone here must know if there's a spring in the M6's base, but I should see for myself early next week. So much for the mechanicals.

The electrical stuff has me totally confused. (I knew this stuff pretty well about 20 years ago; really I did.) It seems to me that for the original Arc application, the resistor may have gotten off easy: a little voltage drop was enough to trick the regulator into backing off, after which the resistor has hardly any current through it at all.

If the Streamlight TL-3 (3 CR123) really is direct drive, and your gadget works there, I'd sure expect it to work in the (2 CR123) Pelican M6 LED, but I don't see HOW it would work in either case.

Here's one way to try to explain my confusion. If there is as you say around 50mA going through the 10 ohm resistor, that's a voltage drop of 500mV. Is what amounts to a battery voltage drop of a half volt enough to significantly change the behavior of a 6V or 9V direct drive unit? And since these units must be running at well over 500mA, maybe 1A or more, to make the LED as bright as they do, there'd *better* be a big change or else that 500mA+ would be going through the poor tailcap resistor.

I'm not saying it won't work -- I'm not even saying I won't try it -- I'm just saying I'm puzzled!

-Inluxication

Re: FS: hi/low spring assembly for ARC LS (NEW)

[ QUOTE ]
inluxication said:
Gadget_lover,

Thanks for the quick response. Someone here must know if there's a spring in the M6's base, but I should see for myself early next week. So much for the mechanicals.

The electrical stuff has me totally confused. (I knew this stuff pretty well about 20 years ago; really I did.) It seems to me that for the original Arc application, the resistor may have gotten off easy: a little voltage drop was enough to trick the regulator into backing off, after which the resistor has hardly any current through it at all.

If the Streamlight TL-3 (3 CR123) really is direct drive, and your gadget works there, I'd sure expect it to work in the (2 CR123) Pelican M6 LED, but I don't see HOW it would work in either case.

Here's one way to try to explain my confusion. If there is as you say around 50mA going through the 10 ohm resistor, that's a voltage drop of 500mV. Is what amounts to a battery voltage drop of a half volt enough to significantly change the behavior of a 6V or 9V direct drive unit? And since these units must be running at well over 500mA, maybe 1A or more, to make the LED as bright as they do, there'd *better* be a big change or else that 500mA+ would be going through the poor tailcap resistor.

I'm not saying it won't work -- I'm not even saying I won't try it -- I'm just saying I'm puzzled!

-Inluxication

[/ QUOTE ]

The same concept was used, but I used different value resistors. I use a 33 ohm resistor to drop the current to 75 ma at 9 volts. The resistor drops 2.5 volts, so the LED gets 6.5 at 75 ma. That's .5 watts for the led and .19 watts for the resistor.

Daniel

Re: FS: hi/low spring assembly for ARC LS (NEW)

Got mine yesterday. Works great !
Thanks gadget_lover /ubbthreads/images/graemlins/buttrock.gif

Re: FS: hi/low spring assembly for ARC LS (NEW)

Glad you got it, AbsoLite. You waited long enough. /ubbthreads/images/graemlins/smile.gif

Daniel

Re: FS: hi/low spring assembly for ARC LS (NEW)

Daniel,

Thank you thank you thank you. The different resistor value helps make it make sense, and so does the fact that the Luxeon 5W forward voltage is a lot higher than I was remembering (6-7V as I gathered from your calculation and confirmed at http://elektrolumens.com/pdf_files/Luxeon_Star_5W_Specs.pdf .) It all adds up perfectly now.

The Pelican M6 LED is just a Luxeon 1W, forward voltage 3-3.5V (says http://elektrolumens.com/pdf_files/Luxeon_Star_5W_Specs.pdf ), but then its batteries are just 6V. So, let's see... if I want 0.5W output, that's 15mA through the Luxeon's 3V drop, and the resistor has to make that 15mA soak up the other 1.5-2V, which would make it 100 ohms, and would dissipate under 30mW. Is cool.

Maybe I'll fiddle around with some values, or rather actual resistors, and see how the light looks, once the Pelican arrives and assuming I can get it lit up disassembled. If some combination looks good, and if it seems like your spring will fit, I'll ask you to make me one. Clipping leads together is one thing; making something that fits nicely and really works is something else altogether.

Candlepowerforum is strangely addictive, but most of it is "bright bright brighter" -- your cheap and cheerful low-power mod is the best thing going.

-Inluxication (aka Greg)

Re: FS: hi/low spring assembly for ARC LS (NEW)

Glad that helped, Greg. I think that in your example you used 0.5 w output where you meant 0.05. It would take 150 ma * 3 volt to make 450 ma (0.45 watts).

Fiddling around is a good way to validate or disprove what you have learned.

I must admit that the mantra in our house is "bigger, better faster!", with "brighter" being added now and then. There's just something about lights that make both extreemes fun.

BTW, several people have written to ask if I'm still making these. I am making them to order, so they are mailed the day after I get the order.

Daniel

Re: FS: hi/low spring assembly for ARC LS (NEW)

Daniel,

I'm not sure what output I _meant_ to calculate, but you're right, what I _did_ calculate was 0.05W. Sigh. You missed that I also did 6V minus 3-3.5V = 1.5-2V -- should have been 2.5-3V! Did I mention I'm a mathematician, professionally?

Right then: Approximate the diode drop as constant, say 3V (low is pessimistic here), so current through the resistor equals current through the diode and is proportional to the LED output power. Voltage drop across the resistor is constant: battery - diode = (6-3)V. Power across the resistor is thus (6-3)/3 times the output power -- equal, with these values. Want 0.1W output? Waste 0.1W across the resistor. No problem for a 1/8 watt resistor, and still a lot less net power than at full throttle. (And the Pelican's use of 6V direct drive for a little 3V-drop 1W Luxeon is an unusually bad case.) The resistance needed for output power X is 3(6-3)/X; for X=0.1W it's 90ohms, very different from the 10ohms the Arc wants.

Having plunged off the deep end, with both the Pelican and now also one of those newly discounted Arc LSH's on the way, I'm expecting to want one clickie adapter for the Pelican (100ohm?) and one for the Arc (10ohm). I'll wait for the flashlights to come, to make sure I like them, to see if the Pelican's tailswitch is physically similar to the Arc's, and to try out a couple of resistor values on the Pelican, but then I'll be ordering from you!

After perusing the related threads, I'm right in thinking that the clickie-switch units you're selling are a bit tricky to get right, but that a twistie-switch adapter is a simple enough DIY job? (Assuming I like the Arc, I'm hoping to get an Arc twistie soon.)

I'm glad you're continuing to make the spring adapters.

Thanks,
Greg

Re: FS: hi/low spring assembly for ARC LS (NEW)

Greg,

Yes, the twisty mod is simple enough to be do-it yourself. It's better that way, as you can re-shape it when it gets bent out of shape.

Daniel

Re: FS: hi/low spring assembly for ARC LS (NEW)

gadget lover,

I'm in for one, I've been using the resistor w/twisty since you first posted your idea. Time to pay ya' back a little. /ubbthreads/images/graemlins/broke.gif

Paypal sent for a 7 Ohm model.

Got to pay Gov. Terminator!! /ubbthreads/images/graemlins/rant.gif Ca. tax included.

Thanx!!!

Re: FS: hi/low spring assembly for ARC LS (NEW)

Just a reminder that I'm making spring assemblies for the Kroll switches. The twisties use a very simple design, requires no special tools and require occasional tweaking, so you are better off making them yourself.

I'm still making these to order, so there is a two day delay from the time you order in most cases.

Daniel

Re: FS: hi/low spring assembly for ARC LS (NEW)

An interesting observation was made by Doug S in the thread about the Two Stage Firefly board. The firefly board uses the same concept as the hi/low spring assembly.

He said that unlike the Badboy, the Madmax is always operating out of regulation. It's set as a constant voltage regulator with a set output of 5V. With a luxeon as a load it can never provide enough current to drive the Vf of a Luxeon up to 5V.

So if you are using a Madmax with the hi/low spring assembly the converter will still be trying to boost the voltage but will be unable to because the resistor will limit the current available.

That explains why my Madmax based lights are brighter than the ARC LS with comparable LED and battery and the same resistor. The Madmax also draws more current.


Daniel

Re: FS: hi/low spring assembly for ARC LS (NEW)

Received mine (10 ohms) today.
I don't have an ARC LS.
It works like a charm in a CNC-Dan 123 light.
I bent the spring a little to a perfect adjustment.
It turns on Low and with an half turn of the tail guard I have the full power.
An o-ring between the tail guard and the body ensure waterproofness in either Low or High.
A must have.

Thanks again.

Re: FS: hi/low spring assembly for ARC LS (NEW)

I found one converter board that will NOT work with the hi/low mod. The Wizard from the Sandwich Shoppe is a buck/boost converter. It will try to suck more currnet from the battery until the voltage hits about 1.5 volts, then it goes unregulated. At 1.4 volts it just stops. No current draw at all.

Using a hi/low spring assembly with this converter will probably give disappointing results and may burn out the resistor.

Daniel