My custom 1D Mag thrower - or how to waste your life building impractical lights

[rice rocket]

Let me know if there's any glaring mistakes or things I've overlooked. This would be my first build. My goal is to build the shortest body Mag by moving the switch into the tailcap. Runtime will be ***, I know. I'll be running this in a 4x1.2v NiMH AA configuration, direct driving a SST-90.

I'm not an engineer at all (mechanical nor electrical), but I know a little Solidworks and a little machining, so I figured since I have access to machine tools, I might as well be somewhat productive in my free time.


Parts:

2D Maglite from Home Depot
SSR-90 emitter from AVNet
1.375" delrin stock from McMaster-Carr
1.5" 6061 aluminum stock from McMaster-Carr
52mm glass lens from DX
50mm optic from DX
Switch (still need to acquire, any leads?)
Arctic Alumina thermal compound
Misc. wires and such

Here's the 3D model.

Battery holder will be made using solid delrin stock and milling out slots with a 5/8" ball end mill. Springs will be flat brass that I'll make a keyway for in the delrin holder.

So that's where it sits now, still modeling. Things I'm looking at:

1. Focal length of DX optic? Right now, I have about 38mm from the base of the heatsink to the glass (and you can see that I've countersunk the heatsink pretty significantly already). Subtract the height of the emitter (7mm) and I'm not sure I'll have enough, even w/ the Mag head unscrewed all the way. Also, the further I countersink the emitter, the more stray light I create. Datasheet says 80% of the light is available at around 35 deg off center, and if I countersink it further, I'll be losing focus OTF.
2. Switch? Ideally, I'd need the lowest resistance switch, with capability to handle 9-10A. Any leads?

Thanks, I'll update as things come together.

 

[A380]

Only can answer about the switch.
I've seen diferents mods using a Judico 10amp switch, but don't know where to buy it.
You could also use a d2flex from taskled so having also lower outputs and only need a momentary switch.
Hope its useful.

 

[The Dane]

The ends of the milling for the batteries will not be square in the bottom when you use a ball mill!

 

[ti-force]

First off, let me start by saying that's a really cool 3-d diagram. What program are you using?

Anyway, I think you're pre-planning very well:thumbsup:. I can't really help you with the switch either. I've seen it done, but I don't remember where or how many amps it was capable of holding. Is their a reason why you want to use NiMH's? The reason I ask; I think it would be much easier to use a single cell, like a Batteryspace 26650 IMR or one of AW's 26500 IMR's. All you would need to do is cut your Delrin down to the ID of the mag tube, then cut the inside of the Delrin, well, you know where I'm going with this. I would think this would be a much easier solution. How do you plan to get the battery negative from the rear of the light, to the emitter? Are you planning to use the tailcaps contact with the body (after the switch) and come off of the body tube somewhere in front of the battery?

Casey

 

[ti-force]

I just noticed you have Arctic Alumina thermal compound listed for your parts/products to buy. You may already know this, but Arctic Alumina compound is not an adhesive/glue/epoxy. It's a grease like compound. The compound is what you put around the heatsink for heat transfer to the body/head. Arctic Alumina Adhesive is what you want to use to glue the emitter to the heatsink (unless of course you're not planning to gule the emitter for some reason). Also, don't confuse Arctic Silver adhesive with Arctic Alumina adhesive. It's stated on the manufacturers website that Arctic Silver adhesive should be kept away from electrical traces, pins and leads. It does have a high electrical resistance, but I don't think I'd try it.

Casey

 

[irv_usc]

not sure, but how much would you really save by making your own heatsink vs buying one of the readily available models?

 

[rice rocket]

The ends of the milling for the batteries will not be square in the bottom when you use a ball mill!

http://i295.photobucket.com/albums/mm153/Chickenthief/Lygter/Blandet/Batteryholder.jpg[IMG][/QUOTE]

Yeah, I know... I was thinking of using the 5/8" ball end mill to get the cylindrical profile, and then using a smaller (probably 1/4") end mill to get closer. I'd also chuck it up in a lathe after and clean up the chamfer created on the head/base with a lathe.

[QUOTE="irv_usc, post: 3294627, member: 52720"]not sure, but how much would you really save by making your own heatsink vs buying one of the readily available models?[/QUOTE]

I'm making my own because I'm trying to get a little bit more focal length to the optic that I'll be using, so the head doesn't have to be unscrewed all the way to make it into a thrower.

 

[rice rocket]

First off, let me start by saying that's a really cool 3-d diagram. What program are you using?

Anyway, I think you're pre-planning very well:thumbsup:. I can't really help you with the switch either. I've seen it done, but I don't remember where or how many amps it was capable of holding. Is their a reason why you want to use NiMH's? The reason I ask; I think it would be much easier to use a single cell, like a Batteryspace 26650 IMR or one of AW's 26500 IMR's. All you would need to do is cut your Delrin down to the ID of the mag tube, then cut the inside of the Delrin, well, you know where I'm going with this. I would think this would be a much easier solution. How do you plan to get the battery negative from the rear of the light, to the emitter? Are you planning to use the tailcaps contact with the body (after the switch) and come off of the body tube somewhere in front of the battery?

Casey

This was all done in Solidworks. Pretty easy to learn, I really only have maybe 10-15 hours into the program. You can download and use their trial/academic edition for 90 days off their website and let me know if you need any help. Or maybe we can start a whole thread on it.

I looked at 26500s, but didn't find much conclusive data. Most importantly, what's the max amperage they can handle as IMRs?

For the tailcap switch, I was just going to electrically isolate the tail spring, and run that into the switch. The body would be used as the ground, but would only have a path to the negative terminal of the battery (or battery pack) through the tailcap switch.

Regarding the adhesives, I have Arctic Alumina Epoxy, but I wasn't sure I wanted to permanently adhere the LED to the heatsink just yet. I got some DX thermal glue with my optic order, which I'll use until I'm satisfied w/ how everything works. I'll use the Arctic Alumina for the heatsink to Mag body so it can be removed.

 

[ti-force]

I looked at 26500s, but didn't find much conclusive data. Most importantly, what's the max amperage they can handle as IMRs?

Here's AW's sales thread: click here. The 26500's can be discharged at 20A and the 26650's are 10A rated. I've never built a direct drive light, so someone with more knowledge than myself will have to add their experiences with this type of setup. I have read about the SST/R-90 drawing too many amps direct drive with an IMR cell though. 12A or so if I remember correcly. I think it was an AW 26500 IMR.

 

[choppers]

This looks sweet. Great pics....I will be watching for updates...:thumbsup:

 

[Linger]

Rice,

Have you looked at nihm discharge graphs? I suspect you haven't as you're asking for a 9a rated switch and the cells really fall off at higher draws.
Before you get to far into building holders, I suggest you bench-test your set-up: connect the 4s nihm to your ssr-90 (thermal pasted to big metal surface) and see how she runs.

My opinion is that your best power source is gonna be an IMR (as it has highest power density). But I'd encourage you to run it on a bench and see what you'll get from the finished product.

Lots of 4s nihm P7 an mc-e builds in the past. At most I'd suggest running a -50, it'll give you a bit more throw but more so you could save the -90 for a project that will make more use of its capability.

 

[Techjunkie]

The DX optic requires 30-31mm from the base of the LED die to the bottom of the glass. I know this because I was surprised to find that the focal distance was exactly the same as a 53x30mm reflector that I was experimenting with and the focal point of the reflector was exactly at or just beneath its bottom (I don't recall which). You'll have to countersink your heatsink a little bit less or you'll be out of focal range.

I'm also building an SSR-90 with countersunk flat heatsink and I wanted to be able to switch between the DX optic and a 40mm deep SMO (Mag Rebel) reflector but as I eyeball it, I don't think the range of the head threads will allow me to switch between 30mm and 40mm from LED base to glass.

By the way, if you're attaching your SSR star with screws, use the Arctic Silver Thermal Compound instead of any of the adhesives/epoxies. It's got much better thermal conductivity.

I think you can get the Judco switch from DigiKey.

1. Focal length of DX optic? Right now, I have about 38mm from the base of the heatsink to the glass (and you can see that I've countersunk the heatsink pretty significantly already). Subtract the height of the emitter (7mm) and I'm not sure I'll have enough, even w/ the Mag head unscrewed all the way. Also, the further I countersink the emitter, the more stray light I create. Datasheet says 80% of the light is available at around 35 deg off center, and if I countersink it further, I'll be losing focus OTF

 

[The Dane]

Rice,

Have you looked at nihm discharge graphs? I suspect you haven't as you're asking for a 9a rated switch and the cells really fall off at higher draws.
Before you get to far into building holders, I suggest you bench-test your set-up: connect the 4s nihm to your ssr-90 (thermal pasted to big metal surface) and see how she runs.

My opinion is that your best power source is gonna be an IMR (as it has highest power density). But I'd encourage you to run it on a bench and see what you'll get from the finished product.

Lots of 4s nihm P7 an mc-e builds in the past. At most I'd suggest running a -50, it'll give you a bit more throw but more so you could save the -90 for a project that will make more use of its capability.

Nah!
Elite 1700 AA's will hold 1,2V @10A draw, so unless theres some serious resistance elsewhere in the build they will fry the LED bigtime