Making a 3 x R2 CREE Torch from scratch... Suggestions?

LEDBE
VanIsleDSM

VanIsleDSM

Enlightened
Joined
Oct 16, 2007
Messages
649
Location
Victoria BC, Canada.
I'm mostly into fixed lighting, but I have myself a lathe now and I've decided I need to build myself a nice LED torch. I'm going to machine it all out of aluminum.

The thing is.. I don't know anything about flashlights! I've never owned a good one. I think the fanciest light I have is a an old black and decker snake light - So I need some direction, though I have come a decent way so far.. here's my plan:

I've already ordered 3 R2s from Cutter and 3 of these reflectors:
http://www.cutter.com.au/proddetail.php?prod=cut738

I'm going to use 6x18650 in series, and because I couldn't find a suitable driver that I liked for this application I built my own:
HPIM1375.jpg


There's a couple of them there next to a C battery.. the larger one is the one I made for my flashlight, as it'll fit perfectly at about 1.5" it's also fitted with a copper penny heatsink on the chip.. the other one I just made so I could get it smaller than a C in diameter... It's a buck driver than can run up to 36Vin, for a max of 9 LEDs in series. Adjustable current output up to 1.2amp via a potentiometer, or optional PWM input. If you want to know more about the driver, check out this thread:
http://www.candlepowerforums.com/vb/showthread.php?t=195274

I have a good push button switch too, I want to keep it fairly water tight for all weather conditions, so I think I'm going to glue some rubber over a hole in the side of the body, with the switch underneath.

The only thing is.. I'm somewhat wondering whether I should go with 8x17670 and 5 R2s now.. I think I need to destroy all the P7 lights out there. But then again never having used a good torch.. I'm sure I would be pretty satisfied with what I've got going right now.

So please, fire away some suggestions.. Like I say.. I've never had a good torch before, I need a bit of direction to make sure I don't overlook any obvious flashlight amenities.
 
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You might start by modifying a M@glight first. Make your own battery compartment to fit the required number of batteries. Since you can make your own now, you can enlarge the inner diameter and still have the advantage of using the M@g head for placing your R2s in....however many that may be.

Look at some of FM's work and you will see he has basically reinvented the M@glight. Realistically, since you are using R2's and the Cree reflectors, you could easily get away with your own head also but finding the proper size Ultra Clear glass could be an issue (you want maximum wow I assume so UCL is required). That's why I say, for now, go with the M@g head and be done with it. Everything you need is already around. You can start looking for other sizes of glass and what not for you follow on build.

Make sure and post your project with lots of pictures and explainations as to what and how you did it. We all like to see what others are doing.

Bob E.
 
Thanks for the suggestion, but I'm dead set on making the entire thing myself... plus I don't think 3 18650s would fit in a little trifecto configuration in the m@g body, I don't think the D size would be big enough.
 
3 18650s sire by side won't fit in a Maglite.

Would a suitable sized Al pipe work as the body and head and such?

Don't forget a good LED heatsink.

Good Luck!
 
1.5" ID works perfectly to hold 3 18650s..

2" pipe with a 1/4" wall with 1.5" ID is readily available.. I'll turn down the outside slightly so it's not quite 2"

I also have some 2 3/4" round stock that I'm going to use to machine the head.. basically the entire thing will be a heatsink.. I plan to make it quite evil looking, some meat tenderizing ridges for heat dissipation on the head, and some medieval mace type tailcap.

I think I may just go with 4 CREE.. then I should still be able to stick with the same configuration.. cutout is usually 2.75V right? so I'll have 16.5Vin MIN. and 4x3.7vF for the LEDs is 14.8V.. that'll be right around with the driver will fall out of regulation.. but there's a good possibility it'll be ok with that.. I need to get another bench power supply so I can start testing at these voltages.

Something else I had considered was to use 5 CREE and still sticking with the 18650.. I could have 1 more group of 2 instead of 3, and the switch could take up the area where the 3rd cell would normally sit... so the body would be 3 18650s long.
 
Sounds like your way ahead than alot of people on here already!! Your engineering looks and sounds like you already know what to do, can't wait to see the finished product! Are you going for a throw light or a wall of light or trying for both?
 
Thanks forrest,

I'm not really sure what the throw/flood ratio will be.. I suppose I'll see once I have the reflectors.. I'd say I'd want something in between though. If I'm not happy with these no matter, they were cheap, I'll just get something else.
 
I own a tri and a penta Cree. Go with as many Crees as you can run. It will get much brighter. I'm currently building an octo Cree Mag.

You can easily run 5 Crees on 6 18650's.

Edit. I like the McR19XR reflectors much better than the Fraens. I have both, and the Fraens are still sitting in the box. Some guys swear by them, but I like the beam so much better with the McR19's.
 
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That's a very unique looking driver. I've never seen one built into a copper heatsink like that. You obviously have some skills in electronics and machining. I've done a couple of multi-cree m@glite mods myself but never built anything from scratch. There are a few things I can say (which you probably already know):

1) Use good thermal adhesive. Arctic silver for the LEDs (but not the driver) and Arctic alumina for the driver.

2) Driver boards overheating is always a problem especially with that amount of power. The LED driver chips usually have a thermal cut out to prevent damage when things get too hot. If this is a problem you may need to use more than one driver (or some sort of multi-chip driver).

3) R2 bin crees are significantly more efficient than SSC P7 and can be driven at a higher level.

4) AW (at the marketplace) is the best place to get protected li-ion batteries. AW's battery capacities are conservatively rated unlike a lot of other brands.

5) +1 on the McR19XR reflectors (available from Sandwich Shoppe). They give the nicest beam pattern I've seen from a Cree. They might cost a bit more but if you've got to have the best...

6) For the lens you can use a good photographic filter. They come in all sizes and have excellent anti-reflection coatings. Hoya pro-1 digital protective or UV filter is probably the one to get.

Let us know how you get on.
 
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Thanks for more advice guys, I appreciate it.

I figured these looked like they'd be pretty narrow.. I like the look of that spread on the Mc-R-19XR... lots of side spill lighting.

Where do I purchase these? Marketplace is down right now unfortunately.

About running more CREEs.. I may just go for another 2 cells for 8 in total and run 5 emitters.

I can't run 5 CREE on 6x18650, the input voltage will drop to 6x2.75=16.5V, 5x3.7V=18.5V for the CREEs @1A

But 8 cells will give me 22V min and 33.6V max.. which will be fine, the limiting voltage on the driver is the 50V caps on the input, they are high quality multi-layer monolithic Japanese ceramic capacitors. The switching draw is easier on the dielectric than a constant voltage aswell.. normal recommendation for standard electrolytic caps is to run about half of the voltage rating for good life span, but with these bad boys I'm not worried about the short duration of 33.6V, the batteries will start dropping voltage pretty quickly from what I understand. These caps are all tested at 10X the dielectric rating for leakage.

But I'll have to get my hands on another bench supply here to do some testing. I had one on long term borrow.. reclaimed now. I've been scowing the internet for something suitable, and i have found some great bench supplies for a good deal at a couple places, unfortunately they weren't Canada shipping friendly companies.

If anyone is interested in one of these drivers, I have extra parts to build a couple more, because of minimum order quantities on the SMT parts. I'm keeping 3 for myself, but I don't need 5, so if anybody wants the other 2 all I want back is the cost of the parts.. I enjoy the soldering so I need nothing for my time. :) $19 would cover everything including potentiometer and wire leads attached for the input/output. Pretty much guaranteed to be the beefiest driver around of it's type.. everything is substantially over rated and low resistance. Done some prelim testing on efficiency, with lower voltage differences from input to output it's ~93% efficient.. higher deltas make for around ~88%.
 
monkeyboy, I didn't see your post before I wrote mine. Thanks for the compliments.

It's not actually built into a copper heatsink, rather, a circuit board that I etched myself.. leaving as much copper as possible for heatsinking.. and less etchant wasted. The driver is efficient enough, and with the penny heatsink on the chip, it's good as is.

I need to learn more about where to get a good lens, I have a 52mm lens from DX, but I'm thinking now that's just normal glass and it'll cut down on my light a lot through reflection? I'll have to read about this specialty glass with the coatings.

As for cells I think I'm going to go with the trustfire greys. I know they aren't the best, but they have great capacity from what I've read, and when you don't get a DOA item they seem to be fine from there.. the greys are apparently a little better than the blues also from what I've been seeing.. Buying 8 AW cells at twice the price of the trustfires plus shipping.. I just can't do it.. if they lasted longer I could justify it, but they don't.. so I'm gonna have to chance the trustfires.

As for a battery charger, I found nothing on the market that I really liked either for a quick charge.. I wanted 1A charge current, temp monitoring for each cell so I feel safe leaving it alone, and a dedicated charging chip for each cell.. If someone knows of something that's a decent price and build like that let me know? but I doubt it exists.. so look out for my custom 5 cycle charger here pretty quick with an adjustable charge current from 100mA to 1000mA with all of the above. I'm designing it to only charge between 0C and 50C, it will auto cut out if outside these specs, but autostart again once back within spec. I'm wondering though, where's the best place to monitor the temp on the cells? on the sides? on the - terminal?

cylces:
#1 qualification, temp ok, overdrained? power ok.. etc.
#2 precondition low drain cells to 2.9v at 10% charge current
#3 constant current charge
#4 constant voltage charge @ 8% current to 4.2V, or modifiable to 4.3, 4.4, or 4.5V for the new cells being developed.
#5 recharge, if cell drops to 4.0V while in the charger for a while it'll start the constant voltage charge again.
 
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I can tell you that you're going to be happier with a penta Cree than a tri Cree. So if you need to run a couple of extra batteries, do it.

Have you put any thought into building a boost driver? You seem to have the know-how.

I like your work. Keep the posts coming. I hope to be knowledgeable enough someday to build a driver for myself.
 
Wow! those are too expensive for my liking.. got me thinking, I may go with a penta CREE, and then maybe 1 more bare emitter for foreground lighting right in the middle of the 5 CREEs with the narrower optics I already have.

I could build a boost driver, but I'm used to building buck drivers for fixed lighting.. I like sucking less current off the batteries, and buck drivers are generally more efficient than boost.
 
VanIsleDSM said:
I need to learn more about where to get a good lens, I have a 52mm lens from DX, but I'm thinking now that's just normal glass and it'll cut down on my light a lot through reflection? I'll have to read about this specialty glass with the coatings.
Click to expand...

A good anti-reflection coating will give you a small percentage increase in transmission but to be honest it's probably not noticible. For an uncoated glass surface, you get about 4% reflection so 8% for both surfaces. Some of the light is re-reflected so the actual loss is a bit less. Good anti-reflection coatings have much smaller reflection in the visible spectrum.

For charging you could get the ultrafire chargers from AW but they're not very fast and can overcharge if left too long on trickle. I don't know if Kaidomain or DX sell anything cheaper.
 
monkeyboy said:
A good anti-reflection coating will give you a small percentage increase in transmission but to be honest it's probably not noticible. For an uncoated glass surface, you get about 4% reflection so 8% for both surfaces. Some of the light is re-reflected so the actual loss is a bit less. Good anti-reflection coatings have much smaller reflection in the visible spectrum.

For charging you could get the ultrafire chargers from AW but they're not very fast and can overcharge if left too long on trickle. I don't know if Kaidomain or DX sell anything cheaper.
Click to expand...

DX sells the Ultrafire WF-139, too.
 
I looked at the ultrafire charger, but it only charges at 500mA, that'll take too long with 18650s, and there's no temperature monitoring of the cells as far as I can see.. I'll feel much better leaving it alone knowing that if a cell gets too hot the charge will cut out.. especially using cheaper batteries.

The biggest cost associated with an 8 bay charger @ 1amp per bay is the power supply.. but I'm come up with an idea to deal with that! I'm just going to put a molex connector on the charger to plug into my computer's power supply.. it can suck off the 5V rail, which can deliver 45A max, on my older 550W PSU.. or one could buy an old ATX PSU for ~$10 from a used computer store and just use that.. I have a few of these old PSUs around my place that I use for many different purposes.

Looks like the cost is gonna be about $10 per bay for the charger.. I've got all the electronics figured out.. now I just need to make some battery holders that can hold all the different types. I only need it now to charge 18650s, but if I'm going through the trouble to make a charger, I should make it able to charge other types of batteries too.. there will be a potentiometer on each IC so I can dial down the charge current for smaller capacity cells.

I figure I'll probably use some combination of PVC piping, springs, and spacers to get a half decent fit for 18650, 17670, 16340, and 14500, am I missing anything?

Can anyone tell me where they think I should take the temperature of the battery? On battery packs that have a temp output, where is the sensor usually located? I'm not sure whether to put it in the middle of the battery on the side, or from the bottom/negative terminal. I suppose it's probably not that big of a deal, the whole battery will conduct heat quite well all over itself, but one spot must be better than another for some reason, hmm.. sometimes I think I stress too much on the little things:)

Edit: Ordering one of these reflectors from DX,

http://www.dealextreme.com/details.dx/sku.5951

Looks similar to the Mc19, I also got the same reflector in a smooth finish to compare.

http://www.dealextreme.com/details.dx/sku.5960

I'm in no rush to get all this done, so I'll test just about everything to make sure I'm satisfied with the build.
 
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Here's a post on multiple battery charging holder.
http://candlepowerforums.com/vb/showthread.php?t=160942

Also -these are cheap and give a nice beam -plus you get an emitter as well :)
http://www.dealextreme.com/details.dx/sku.11621

There is an R2 model but if it is WH/WG tint it won't look as bright as th Q5 WC

The driver part is screwed in -i turned mine off,but i'm sure it could be unscrewed just as well.
The reflector makes a nice beam for an Ostar as well once you remove the threaded part.

EDIT : It will be interesting to see how those reflectors you ordered go -they seem more a length you would use for the Seoul -the McR-19-XR are about 20mm long with a 17mm hole at the output end.

Cheers
Dom
 
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