Sold/Expired Feeler - Streamlight SL-20X and Sl-20X-LED Drop-in LED Conversion

[CDP930]

Hey Harry

Been a while, hows progress?

 

[HarryN]

Hi, its been a slow summer on this project - sorry. The good news is that I have been working on finding all of the little parts to make it, and buying things.

This past week I dropped another $ 250 into electronics parts.

It is still coming, I am just hesitant to say when right now.

Thanks for your continued interest.

Harry

 

[jaundice]

Please add me to the interest list for an SL-20X.

One question: would the streamlight tailcap dimming switch work to dim the LED? If so, this would be the perfect setup. I have one of the dimming tailcaps, and would be happy to lend it to you for testing. As I understand it, the dimming tailcap is just a circuit that provides variable resistance to the circuit.

I really think your idea of using a 9AA battery pack is excellent. The light could still be charged via the stock charging cradle.

-John

 

[HarryN]

Please add me to the interest list for an SL-20X.

One question: would the streamlight tailcap dimming switch work to dim the LED? If so, this would be the perfect setup. I have one of the dimming tailcaps, and would be happy to lend it to you for testing. As I understand it, the dimming tailcap is just a circuit that provides variable resistance to the circuit.

I really think your idea of using a 9AA battery pack is excellent. The light could still be charged via the stock charging cradle.

-John

Hi John, Thank you for your interest, you are added to the list.

My reasoning for the AA pack compatability is that I like to have a way to run lights on both R and Primary type cells. I am planning to keep a 9AA pack loaded with the AA Li Energizer cells for use in the car for emergencies, as this will give the lowest temperature performance and least cell self discharge.

I guess you could use that cradle to charge a 9AA NiCd or NiMH series pack if you attach it to a hobby charger, but I don't think it would work with the stock charger attached.

The driver is a constant current boost circuit, so it will try to drive at a constant current regardless of the input voltage (over a range) If the tailcap works by resistance only, then it will not help us. If it works by pulsing the power on/off quickly, then normally the drive current to the LED will pulse at that same frequency, which might be useful or not.

I have used a fairly large inductor and caps in this driver to help smooth out the current, deal with any system noise and enable operation at low temperatures. The goal is (-40 F, which is also -40 C) It is possible that the tailcap dimming effect might be smoothed out to almost nothing under most conditions.

Thank you for the offer to borrow one though. I should take you up on that in the near future.

Harry

 

[jaundice]

Thanks, Harry.

I live in BigChelis' area, in fact I've been to his apartment a few times. I can give you the dimming tailcap the next time you're down here, or just send it to you. It sounds like you have a few SL-20x's, so if you like to try it out on an incan version, you're welcome to it. It's a cool piece of gear.

I'm a bit confused about your statement that the stock charger wouldn't charge a 9xNimh AA pack. Correct me if I'm wrong (it happens alot!), but isn't the stock DC charger just putting in straight DC power from a car DC system? From what I understand, although this is nominally 12v, the actual voltage is like 14.4v. A 9xAA Nimh pack at full charge would be 13.5v (9x1.5v charger termination voltage), so wouldn't this successfully trickle charge from a car DC source? I realize it would be slower than the stock 6v battery, but it would still charge.

Thanks,

-John

 

[HarryN]

Hi, good to know you are close to BigC. I need to talk to him about testing one of these units in his spheres anyway, maybe in Oct.

As far as charging - your question made me look at the SL-20x (well, one of them) again. I have both the wall plug versions and car plug versions of the charger. The wall plug unit that I have is rated at a nominal 12 volts, 500ma, and feeds into the switch.

I have not pulled the switch assy from one of these lights yet, but I can see a circuit board in there from the front. I am "assuming" that that board does the charge control of the 5 x 1/2D NiCd pack. Exactly what is going on in there I guess is still a mystery to me. :thinking: Maybe I should try making up a probe and putting it in there to see what is happening.

If that pack just had 500ma of 12 volts sitting on it all of the time, I would have guessed that it would over charge, but I will admit that I have seen RC guys do that stunt directly from car batteries in a nearly dead short. Not that I reccomend that approach.

I guess in summary - I don't know if that will work or not. If it did, that would be really neat, because then it would only be pulling about 1 amp from those AA cells, and run time would be pretty impressive.

 

[PhillyRube]

Is this still in work??? Also, is there a better battery? My SL20s eat them, and they mostly sit on charge, waiting......

 

[HarryN]

Hi PhillyRube,

The project is still in the works, but has hit a snag - economics. I am building these mostly as a serious hobby, not really for profit. I am pricing them fairly close to break even on the parts to build each unit, so I am absorbing all of the development costs as "hobby money". I don't have a problem with this appoach, as it makes sure that I don't take anyone's money until I am really confident in what is shipping.

It was supposed to be sort of a gift to police officers, being able to buy something like this, at it's real parts cost.

The challenge I have though, is that I have about $ 2,500 in development costs so far, and about another $ 1,000 to go. (this is real cash out the door, not including my time) My "hobbies" are all pretty much on hold as I am only working part time right now. The last $ 1,000 will give me 2 - 3 working protos, assuming that it all really does work, which is "should", but I can't be 100% "certain". That is why I am unsure about how to come up with funding for the last portion of the development until I get a second income going.

If you have some ideas, I am all ears.

As far as battery packs, if you have the 5 x 1/2 D pack, I am pretty sure that the same pack works with the similar mag charger light. They released a higher capacity pack, but I have not tried it out yet.

http://www.maglite.com/rechargeable.asp

For this particular drop-in, I like to have both rechargeable and primary cell based solutions, so I designed it to accept almost anything that can drop into a 3 D configuration, example:
- 9 x AA holder
- The standard 5 x 1/2 D pack
- 3 x protected LiIons
- and if we are lucky, it might even work on 3 x D NiMH, although that one is a real push as the voltage is pretty low

I expect that only the 5 x 1/2 D combo will work with the cradle charger though.

Sorry for the delay, it is just a matter of getting some more consulting projects.

Take care,

Harry

 

[Pomosapien]

Hi HarryN:

Would you please add me to your list? I have an old sl-20 that I have had for over 20 years and it works fine. Would your design work on it as well?

Thanks.

 

[HarryN]

Hi Pomosapien - I added you to the list - thanks for the interest. Sorry for the delayed response - I was on the road this past week.

I am not 100% sure if it will fit or not, but when I get that far, we can figure out a test fit method to make sure it is going to work for you before you commit. I suspect it is very close though, so if there is an interference, we can work through it.

Harry

 

[tjhabak]

I am interested in an SL20-X drop-in.





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[motorwerks]

I had totally forgotten about this. I Somehow managed to run into the Terralux drop in on some site, and ended up doing a google search for SL-20X mods and this was one of the first things to pop up. Any news???

 

[LiterLeaner]

I had totally forgotten about this. I Somehow managed to run into the Terralux drop in on some site, and ended up doing a google search for SL-20X mods and this was one of the first things to pop up. Any news???

I never got contacted after the initial back and forth... I have no idea what happened to this but in other news the Terralux I have in both of my SL20's are still working great!

 

[crescentstar69]

I would be interested in one for my SL20X LED. Please add me to the list.

 

[HarryN]

Hi, Thanks for the continued interest. I put about $ 2K and a lot of time into this project and still have about $ 1 K plus more time to go to finish it up. Frankly, that was just not possible in 2011, but I have it on my list for 2012. It is not so easy to put that kind of money into a project that will never be profitable, so just keep in mind that I am doing it as a serious hobby, when I have the time and money.

Harry

 

[speedjunkie]

I would be interested in getting one for m SL20X. Please add me to your list. Thanks.

 

[tjhabak]

Any hope of these still becoming reality?

 

[X_Marine]

It would be nice.
The SL-20X is such a nice package with the new NiMh battery pack, and easy to keep charged.
The TeraLux led mod helps but it could be so much nicer.

Here's hopin.. ')
X/BillyD..

 

[Deep6Osama]

I would be interested in one. I am running Malkoff Drop ins in my sl-20x. Just seems like this class of light is so over looked for modding.

 

[tjhabak]

Another option is the Malkoff drop-in. It's a really nice set-up. I just have two SL20's!