Asperical Maglite Mod

Hey all, I'm planning to build a super thrower LED Maglite, and would like to run a couple things by you. I've combed through tons of threads on this subject, and I think I've come to a basic understanding, but I still have a couple of questions I can't resolve. So far, I've found that:

1. The Cree XR-E would be the best option for an emitter because puts out most of the light straight ahead, and doesn't have an odd pattern. Higher bins mean higher brightness; an R2 should be a good option.
2. An AMC7135 based driver is cheap and reliable. It somehow senses how much voltage the LED needs, and burns off the rest as heat. The current is regulated, in this case it should be to 1050mAh. The driver won't boost the voltage to keep the brightness consistent as the batteries drain, but it won't flicker either.
3. A 3D light would be ideal because the 4.5 volts from the battery will be closest to the 3.7+whatever the driver leeches volts that are required, so not too much power is wasted.
4. This DX SKU 12834 aspherical lens will just drop in if I grind most of the reflector off and use it as a retaining ring.
5. The H22A heatsink will keep the emitter and driver from being damaged, and keep the emitter low enough in the body so that the lens can focus it.

Assuming all that's correct, I'm still not sure where to solder the leads onto the driver and emitter (can't find any pictures for some reason). Also, where do you guys get your emitters and drivers? I can't find that exact emitter on DX, and although they do have the driver, they only seem to come in 10-packs.

Thanks!

DX Link Removed, replaced by SKU - Norm

Your good on 1 and 2. For #3 check out the Alkaline Battery Shootout thread and scroll down a bit until you find the section for D cells. If you plan on running alkalines then I'd recommend 4 C cells in the 3D (use a PVC pipe as a tube adapter) as 3 D alkaline cells will not provide enough voltage under load for any reasonable amount of time. Nimh batteries would be better as the voltage under load will sag less. I have the same DX lens and you will be fine. As for the H22A heatsink it will work somewhat... To obtain the proper focal length of the aspherical lens you will have to unscrew the maglite head past the rubber o-ring. Or you can grind the lips of the heatsink off to push the heatsink farther into the maglite body tube.

For drivers I've used a multimode AMC7135 driver from KD (S003256), or you could use a cc/cv driver like the one at ShiningBeam 3 Mode-Perfect-Regulated-Circuit and not have to worry about alkaline battery voltage sag with 3 cells. On the underside of the driver the inner circle is batt(+) while the outer ring surrounding the inner circle is batt(-). As for the emitter its hard to find a genuine XR-E R2 from sites like KD or DX. I have had consistent results with a Q5 EZ900 XR-E from DX (SKU # 11023), its only 1 bin below the R2. If you want a genuine R2 then you'll most likely have to order them from cutter.

I hope this helps you out on your build. Let us know if you have any more questions.

Sales Link removed - Norm

Just a heads up now is not the time of year to be ordering out of China they are having their holiday you can expect an extra week or two on shipping
I usually get things in 10-14 days but have waited over a month when ordering in January, I'd wait till February but you may have better luck

Thanks, that's really helpful. That 3 mode driver says that it regulates current, but you're saying it will keep the voltage constant, too? I was looking at the AMC7135 single mode ones because they're supposed to be reliable and durable; how reliable is this driver in comparison?

I might just get a Q4, then, since that seems to be the best easily available one without a mounting board. I'll be sure to wait until the new years craziness is over.

The amc7135 based drivers are pretty reliable, they have very few parts. The one mode only contains the 7135's. Cutter maybe another option to get you a cree XR-E with out the china holiday delays. I have purchased stuff from there in the holiday season. They get backed up pretty bad. It took me about 2 months to get my order and I ordered a few days before the holiday. Thinking it would ship out before the holiday. I didn't order quick enough and it got hung up in the traffic. You could try the 3 mode driver from shiningbeam sku 1218, If you are looking for the most you can get out of the XR-E. It will over drive the led a little. Has been done many times on here if you search. I used it in a HS-802, helped alot from the stock driver. It is also a amc7135 based driver. Never had one fail yet and used several dozen or so of them in the past two or three years.

I've used several of the shiningbeam 3-mode perfect regulated circuit (SB PRC for short) and haven't had any issues at all. I mainly use them in P60 style lights but have also installed one into a 3D mag running a SSC P4. I've also used several variants of AMC7135 linear regulators and they work fine as well. The AMC7135 based drivers require a Vin (Vbatt) of: Vf of the LED + 0.12v (driver overhead) + resistance (host, springs, etc.). So for a XR-E @ 1 amp your looking at 3.7v (initially, Vf will go down somewhat with heat) + ~0.15v. Once Vin is too low (battery voltage sag) the LED will not be driven at the full 1050mah and will run at a lower current. So for the longest regulated runtime on alkalines with a Vf of around 3.7v 4 cells would be ideal.

The SB PRC operates differently as it is both a buck and boost circuit to maintain a constant 1000mah to the LED. To give an example how it works a basic explanation of how watts is calculated is needed:
Volts X Amps = Watts

An XR-E @ 1 amp will have a Vf of ~3.7v, this calculates to 3.7 watts.
Drivers are not 100% efficient (power in does not equal power out), but to keep this example simple I will assume 100% efficiency.

With a Vin of 4.5v (3 fresh alkaline batteries) the current draw from the batteries will be ~0.82 amps (buck). 4.5v X 0.82A = 3.7 watts
With a Vin of lets say 3.5v (3 used alkaline cells) the current draw from the batteries will be ~1.06 amps (boost). 3.5v X 1.06A = 3.7 watts
So initially the driver will be a buck circuit. As Vbatt sags over time the driver will automatically switch to operating as a boost circuit and pull more amps from the batteries to maintain the full 3.7 watts to the LED.

Efficiency of buck/boost drivers are most commonly in the 80 to 90 percent range. In a 80% efficient circuit if power out is 3.7 watts, then power in would need to be 4.625 watts.

I built myself an aspherical Maglite once with a H22A heatsink and a XR-E. Turned out really great with the Kaidomain aspherical lens.

rayman

Wow, it's been forever since I started this thread... But I think I have everything I need for the build now (better late than never, right?). I ended up going with a linear dx driver (SKU 25518) since all the multi mode ones I could find started on the low mode, which I didn't like. I'm planning to use AS5 paste for the led and heat sink, with a little epoxy added on to hold them in place (that way it should conduct heat better than the adhesive thermal compound and it won't be completely permanent in case I have to replace something). Right now I'm looking at the disassembled parts, and I just have a couple clarifications to make on the driver.

1. It came with leads for the LED, I solder the leads for the battery onto the back, right? Positive on the center circular contact, negative on the outer ring contact?

2. Does the driver need to be attached with thermal paste, or can I just leave it hanging or use regular epoxy to affix it to the heat sink without risking damaging it?

1) Yes you are good there. If you can I'd recommend replacing the stock wires with silicone or teflon wire.
2) If you are using 3 alkaline or nimh cells there is no need to heatsink the driver. If you plan on using 4 cells then yes you will need to heatsink the driver. You would need to use a thermal epoxy that is not electrically conductive. Fujik or Arctic Alumina works well.

Is your led on a MCPCB or a bare emitter? If its a bare emitter then you need to use a non-conductive thermal epoxy. If its on a mcpcb then AS5 should work fine. I usually use Ceramique as it is a bit cheaper and electrically non-conductive.

Thanks, the LED is mounted on a star, so there shouldn't be an electrical conductivity problem. I'm using a 4D Maglite, so 4 alkaline cells. How and where do I heat sink the driver so that it won't be damaged?

Depending on which version of H22A's heatsink you bought (P7 or DHS flattop) you will want to attach the driver (LED side) to the heatsink directly. You can find some pictures of how I do it in my build threads in my signature. Also, in this build thread by LivingDayLight there are pictures of how he attached the driver to the heatsink.

Looks like I'll have to get some non-conductive Arctic Alumina, then, the paste in that link looks a lot lighter than the AS5 I have. I actually got one of the prototype Rebel Mag sinks from h22a, hopefully it will seat the emitter deep enough that I won't have to unscrew the head past the O-rings to reach the DX aspherical's focal point. Thanks again!

Hmmmm.... I connected the driver and LED to 4 AA batteries to test them. The LED lights up and seems bright, but when I replace it with a multimeter it says that the driver is only putting out 500 mah instead of the 1050 mah it's supposed to... Is the driver actually faulty, or is there a reason for this? Also, the driver seems to get very hot after a couple seconds of running, is that normal?

Nevermind about the current output; I wired the multimeter in series with the LED instead of replacing it and it reads out the correct value. I'm not sure exactly how CC drivers work, but apparently they need the load.