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

[HarryN]

Hi - Time for an update.

The original proof of concept version that I built was sort of hacked together and looked pretty ugly, so I didn't show it to too many people. What it did show is that it will work, fit, and give a reasonable :naughty: amount of light.

One of the big challenges was finding an LED driver that could keep up with the power demands from this relatively low voltage pack. The power draw is not that high, but most powerful drivers just don't go that low.

I hand built some versions that would work, but not down to the (-40 C) goal I have in mind. This does not mean the battery pack can will operate at (-40C), as this still needs to be tested, but the electronics and LED package will.

I hired a local, semi retired electrical engineer to help design a custom, robust, constant current driver for this project. The first small batch of PCBs is on the way to me, and then it needs the components soldered on, etc. It will take me about 3 weeks to obtain all of these parts, get them soldered on, and do some testing. Hopefully, it all will work. If not, adjustments to the design will be needed, and another round of proto testing. This is about a 6 week cycle.

 

[HarryN]

Thank you for all who have expressed interest. The project is moving ahead, regardless of the size of the list. I want some of these for myself, and if I eventually sell about 100, then I come close to breaking even. If not, then that's life.

Since the list is so short, I am going to ask the people on the list to not consider themselves as much customers, as "customers and testers". This means that I will ship one out to you for your own testing and ask for feedback. If you are happy, then you can pay for it. If not, let me know what you think should change and return it. This offer is only for public safety employees, such as police officers, fire, ambulance, etc.

Please keep in mind the goal of the project is high quality lighting, as in good spectral quality to make items that you can see easy to identify. The effect of this is that the total amount of lumens is reduced – its just physics. The total light output is higher than the standard SL-20x bulb, but it is not going to come across like a superlight.

I want to be very clear on this point. My beef with most LED lights is that I can't see sufficent details and color contrast. This effect causes the brain to spend a lot of time to interpret what something is. The intention here is to make it so that the "time to recognize a detail" is very short.

I could build it brighter, but there is only so much heat that can be moved from a hand held light without it getting quite warm. That limit kicks in around 15 watts for a constantly on light. The nice thing about this setup, is that it is modular enough that over time, as LEDs improve, it will be relatively easy to keep improving the light output of this drop-in without replacing the whole thing.

The list mostly helps with planning and parts purchasing. The challenge is not so much parts pricing, as much as parts availability. Some electronic parts and LEDs are on allocation, so if I don't order enough, then the wait can be potentially months to get more. I have tried to design around this, but it is always a potential.

I will post some pictures in about 3 weeks of the progress.

Thanks

Harry

 

[motorwerks]

Im interested in one for a SL-20X and then MAYBE one for my OLD SL-20 (I know I didnt put an X behind it )

 

[HarryN]

Im interested in one for a SL-20X and then MAYBE one for my OLD SL-20 (I know I didnt put an X behind it )

Hi - added you to the list on the SL-20x.

I don't have an SL-20 but I am not against the general idea, depending on what is involved in pulling it off. I need to focus on just getting the basic ones done first of course. At that point, perhaps you could ship it to me and I can take some measurents.

As a starting point:
- Does the SL-20- use similar battery pack as the SL-20x, as in the 5 x 1/2D pack or something else?
- Does it use the same bulb + reflector combo as the SL-20x?

Those answers will help a lot with estimating the scope of work involved.

Thanks

Harry

 

[motorwerks]

LOL I just rebuilt my SL-20....... same Bulb/Reflector, and battery as SL-20X they just had a different switch/Charger. :naughty:

 

[HarryN]

LOL I just rebuilt my SL-20....... same Bulb/Reflector, and battery as SL-20X they just had a different switch/Charger. :naughty:

Hi - Thanks for that info.

On the SL-20x, from the front, there is a sort of cylinder inner diameter area for a short distance, then a bevel, then another cylinder shaped area that is a smaller diameter. Does this part look similar?

The reason I ask, is that my drop-in carries the heat to the inner wall of the head and those ID dimensions are reasonably important.

We can see if the standard one for the SL-20x fits both lights and you can go from there. Even the SL-20x and -20x-led version of the light are enough different to be a slight pain. I am working on trying to make those versions identical, but that is not a given yet.

 

[motorwerks]

I own one of each so I can try and snap some pictures later. But to me it looks like about the same room under the bulb/reflector.

 

[HarryN]

I own one of each so I can try and snap some pictures later. But to me it looks like about the same room under the bulb/reflector.

That should be close enough. When you get your first one, you can try it and see if it fits in the "non x" version as well. It mostly is just a matter of the diameters of the straight wall portions.

The switch area of the light is so busy, there is no way I was going to attempt to seat to that region.

 

[HarryN]

I took some measurements with CPFr gadget_lover this week on possible alternative battery options for this project.

In addition to the conventional packs that Streamlight provides, it "should" be possible to use some other combinations in the SL-20x version, for example:

- 9 AA to 3D adapter as long as the total stays under 12 volts. (9 x 1.5v x 1.5 ah = nearly 20 watt hours) (NiMH, Energizer Li AAs, probably not NiZn cells)

- 3 x 26650 cells, with a sleeve adapder. (3 x 4000 mah x 3.7 volts = 36 watt hours) for a 15 watt hour draw - kind of warms the runtime heart doesn't it.

- Cut down version, 2x D cells long for the 6 AA to 2D adapters or 2 x 26650

The driver electronics should be able to deal with this voltage range. This of course has yet to be tested, but some might find it interesting.

On the SL-20X-LED version, obviously the tube sleeve and battery adaption is different, and I doubt that Streamlight ever intended for their 3x5mm LED driver to be hit with 12 volts.

The boards seem to be stuck in customs right now. (fabricated in AUS believe it or not - one of the few places with some particular capability I needed)

 

[HarryN]

You guys probably were thinking that this project was just vaporware, but actually, real progress has been made.

The next 3 weeks are going to be super work busy though, and I did find a board design error, so there is a delay. Sorry about that.

https://www.candlepowerforums.com/posts/3389024#post3389024

 

[021411]

No worries.. I'm patiently waiting and can't wait to evaluate it. :thumbsup:

 

[CDP930]

Ditto

 

[HarryN]

I forgot to tell you in that update post that the link takes you to a picture.

 

[mlatino]

Hi Harry, I heard about this site/thread from a co-worker.. Please sign me up for a SL-20X-LED when they are available.
Thanks,
Matt

 

[HarryN]

Hi Matt,

Thanks for the note - I added you to the list.

I had some business travel the last 2 weeks, but some of the parts have arrived, including a bunch of LEDs from Lumileds. The parts list for the drive board is a bit complicated and they come from multiple suppliers, so it takes a little time. It probably takes me even longer since I sweat over every part decision.

 

[motorwerks]

If ya ever need a sample it just dawned on me where you are located. I come into the bay once every other month or so. My office is in Pacifica and my wife and I have some friends in San Jose so I can swing one or the other by.

 

[HarryN]

If ya ever need a sample it just dawned on me where you are located. I come into the bay once every other month or so. My office is in Pacifica and my wife and I have some friends in San Jose so I can swing one or the other by.

That sounds great. Let me know when you are in the area next time and we can do a test fit up and see what you think. Depending on timing, I can go either place or you guys can stop by and we can grill something.

 

[HarryN]

I had a chance to test the stock SL-20x-LED on BigC's light test sphere (see the LED forums section). The stock version tested in at 185 lumens, very close to the Streamlight rating of 200 Lumens. Light testing of a focused source like this challenging, so it is entirely possible that 200 Lumens is real.

It would have been nice if I could have had a finished proto with me to test at the get together, but alas - it wasn't finished. Still picking up parts, but work has been a bit distracting the past 2 weeks.

Take care,

Harry

 

[CDP930]

Hey Harry

How is progress?

 

[HarryN]

Hi, progress has been a bit slow but is picking up again. I should probably stop making a "ready by xx date" since I missed them.

I have more parts and am revising the BOM (bill of materials) to correct for some errors. What can I say. The good news is that it was only a couple of parts.

There are some shortages of relatively common electronics parts with 8- 10 week back orders unless I spring for entire reels of parts, so this takes a bit more searching. A part might only cost $ 0.50 each, 2 needed per light, but it is hard to justify buying 2500 of them to shorten the lead time. 100 - 200 parts is ok even if they are never used, but 2500 x a few part types x a dollar each = adds up to a budget problem. It is not a big deal, just takes some searching time.

I am not sure about anyone else, but the tailcaps of my (purchased used) SL-20x's have some pretty decent corrosion around the spring base. I obtained some of CAIG labs deoxit to test on it, and am attempting a "before" and "after" test for resistance. The corrosion was bad enough that the "before" reading is difficult to obtain a steady number, but definitely it is significant.

If the deoxit works well, I am considering to just put some in with each drop-in as part of a "fix up kit". Possibly even a new lens if I can obtain a batch of them easily enough. Anyone else see white stuff where the spring touches the tailcap?

Sorry for the long wait. This project is self funded and timing sometimes has to wait for the other bills to get paid first, and my pay comes in monthly.


Thanks

Harry