2D Maglite mod questions

My first post (and hopefully one that won't irritate the CPF community)! I've been lurking for a while, and love this site.

A little about myself: I'm an arson investigator, and spend most of my time crawling around in dark, smelly, carcinorgenic fire scenes. Needless to say, flashlights have become extremely important to me. I currently use an Inova T4 as my general purpose light; it can be used at fire scenes, as well as a tactical light with my sidearm.

I'd love to modify my old 2D Maglite to something like what 3rd Shift has done: https://www.candlepowerforums.com/posts/2134721

However, I do have some questions...I've already bothered him, and thought I'd spread the irritation I have little EE knowledge (like-don't touch the wires), so I'm having some issues.

1) He used a direct drive of 4 Crees off 6AA through a 5W 1 Ohm resistor. What are the advantages of doing it this way vs. using a driver?

If I were to get an 8AA-2D adapter, use 2700mA Powerex AAs to power 4 Crees:

2) Should I wire the emitters in series or parallel; what are the benefits of each? 3rd Shift's tutorial says that his emitters are in parallel, but aren't they also in series?

3) Should I try to supply 1Amp to each Q5 emitter? Why or why not?

4) Would a single 1000 mA Downboy be able to supply that current to all 4 emitters? How would I figure out the resistor needs for the Downboy?

5) What's the difference in functionality between plastic optics and reflectors in 3rd Shift's mod?

Thanks in advance, and I really have tried researching these questions, but I've not been able to find an answer that I can understand. I'm anxiously awaiting enlightenment! (pun intended)

1. The main advantage of direct drive is the cost. A sub $1 resistor vs. a $20-$30 driver. But it also wastes power. How much will depend on the Battery/LED voltage mismatch. And you will see declining output as battery voltage drops with a resistor while a drive has more constant output.

2. Personally, I always wire LEDs in series. This keeps the same current through all LEDs even if the voltage drop across them are slightly different. In parallel, an LED with a lower Vf (forward voltage) will draw more current. If your LED's are closely matched and you are careful to measure each LED current to prevent overloading, parallel may work better in some situations. I am lazy, I go series and use step up drivers.

3. One amp is the max rated current and will give you the brightest output. It also uses the most power whichresults in more heat being generated and shorter battery life. More current = brighter lights = shorter runtime is an unavoidable truth of flashaholism.

4. A downboy is a step down driver, no resistor is needed. Constant current drivers like the DB1000 adjust their ouput voltage to supply the set current on their output to the LEDs. A step down driver needs Vbatt > total Vf of the LEDs. Four crees in series at 1A is about 12.5 Vf (been there, done that) so you would need battery voltage higher than that. When Vbatt is < Vf, the driver just goes direct drive like it wasn't even there and you get declining output like with a resistor as the battry depletes. I used 8aa-2D to drive four Crees using a Shark driver. The Shark is a step up driver. It boosts the ~10V of the freshly charged 8aa pack to the ~12V to drive the LEDs at 1A. The Shark also has an adjustment on the board that you can set to whatever current you want, up to ~1A maximum. The risk with a step up driver is that if Vbatt is > Vf, it goes direct drive and can over power the LED, burning it out (been there, done that also).

5. Optics vs. reflectors is highly dependant on the specific combinations used and personal preferences. In general, there will be more losses with an optic than with a smooth reflector. However, the beam seems to be a little smoother with less artifacts. To smooth the beam with a reflector, you have to add texture to it which then increases the losses. In general if I need a spot I lean towards reflectors and if I need a flood I lean towards optics. Right now, most of my multi-Crees are being built using the Fraen faceted reflectors since they have lots of bang for the buck at around $1 each. McR19XR aluminum reflectors are great but $15 each adds up quick. I've also used the Cree XR-E optics and it's very close to the faceted reflectors.

Any other questions, just ask. Be be warned, as you can see I tend to babble.

If your "old 2D Maglite" is so old that it doesn't have a "D" in the serial number, forget LEDs in it because you will not find a heatsink that fits. On the bright side, 8 2700 AAs will fit without boring, so the much more powerful 1164 would be ideal for distinguishing shades of black.

A newer Mag 2D won't fit most 8AA without machine work (hence the popularity of 6AA to 2D adapters), but Lithium-ion Ds that do fit should have more capacity and work fine in regulated LED applications. The ones available right now are unprotected, so be sure to select a driver that shuts off at 6.5v or so.

We live in strange times, with unprotected Li-ion Ds available for cheap and 6AA-2D adapters not available at any price. Otherwise I would recommend a ROP for an ideal first mod. Cheap, simple to DIY and fantastically bright! Perhaps we could interest you in a 2C?

Firecop,

Since you plan to be in tight places, and even with a smooth beam, there is a big chance that you may blind yourself when the XR-Es are running at full power. I suggest that if you do go the LED route, use a boost circuit, like the Shark driver from the Sandwich Shoppe or the Fatman from TaskLED. With these two boost drivers, you can hook up an external potentiometer so you can reduce the current, and, therefore, the brightness, anytime. It can be easy to find a potentiometer small enough to mount to the side of your maglite. You would just need to drill a hole in your maglite (above or below the switch) for the potentiometer. Most pot components should have the hex nut included to tighten the pot down to the body. Finally, a little silicone sealer can be applied to this hole if you need any extra waterproof-ness.

With this potentiometer sticking out the side (you can attach a knob, too), you can make this thing run dimmer for extra runtime if you need it, or extra brightness to spot things a little further away or to light up a room. Saved eyesight is worth the little extra work to add the pot!

I have 4 of the Seoul P4 emitters in a 2D mag (not as bright as 4 newer Q5 emitters however), and it is a great multi-purpose light. I have 4 reflectors with a narrow beam, so close-up work can be a pain unless I do something about it. I use the Fatman circuit to boost the voltage from 6 average NiMH AA cells (now the Eneloop type). It is a nice set-up and I get great runtime even though each LED is running at 1A (roughly 15W total). The thing I love about this light is that I can turn all the LEDs down below 100mA for super runtime! Great for those long nights or for any emergency situation. Luckily, I managed to hook up a potentiometer to the flashlight in a very unique way to dim the light to a very comfortable level for close-up work. I have the potentiometer positioned in the head in a way where the main body of the pot is fixed to the body of the flashlight, and the shaft is attached to the head of the flashlight. When I need a dimmer light, I just turn the head clockwise. Then I can crank the heat counter-clockwise to make it run at full blast. Strangely, even though twisting the head to dim the light is very nice, I can imagine a side mounted potentiometer would be quicker to find and easier to turn. Turning the head requires two hands while the pot on the side can be turned with an extra finger when in one hand. It feels more natural to turn a side-mounted pot. Plus, I am not sure if your hands are wet or oily if turning the big, smooth head will work. With a pot on the side, it should be easy to turn in these conditions, or even with big gloves on.

Whether you choose the LED or incandescent route, good luck with your mod! It will be a lot of fun and you will learn much from a mod like this. I can imagine that cost will be the biggest issue. Incan seems the cheapest. You can do a super-cheap LED mod with using series-parallel mounted Edison Opto LEDs and the correct battery pack (using the right resistor). Finally, there is also the very satisfying route of using the Cree XR-E Q5s, a boost circuit, and a 6AA pack. optcs may be best for you (or heavily stippled reflectors), as even those cheap reflectors mentioned (from fraen), may give you a too intense of a beam. Well, there I go blabbin, too!

-Tony

Outstanding, gents, thanks for your (very quick) responses!

Gryloc-great idea about the pot! I think I'll definitely work that into my mod.

BFG-you mentioned an "1164"...I don't understand the reference. And, yes, my Mag is pre-D - I did say it was old . Would a newer Mag head fit on the older body? I do like the idea of 8AA-2D.

Don-you're not babbling, you're teaching. You answered all my questions, but I'd like to get some clarification:

1) The specs I see about the Q5s show a driving voltage of 3.7. Does this mean that I need to supply 3.7*4=14.8V? You list 12.5Vf....I'm confused.

2) I thought I'd verify how to hook up in "series". I'd solder the + lead from the switch to the "+" on the first star, then connect the first "-" to the second "+". Continue until the last star's "-" gets connected to the "-" from the switch. Am I correct?

3) Lastly, a question about the Shark/DB...Do I need only one driver for multiple emitters? It seems to me that if I need 4A total for 4 emitters, a single 1A driver will only supply 1/4 my power needs.

Thanks yet again for the warm reception and assistance!

Firecop said:

Outstanding, gents, thanks for your (very quick) responses!

Gryloc-great idea about the pot! I think I'll definitely work that into my mod.

BFG-you mentioned an "1164"...I don't understand the reference. And, yes, my Mag is pre-D - I did say it was old . Would a newer Mag head fit on the older body? I do like the idea of 8AA-2D.

Don-you're not babbling, you're teaching. You answered all my questions, but I'd like to get some clarification:

1) The specs I see about the Q5s show a driving voltage of 3.7. Does this mean that I need to supply 3.7*4=14.8V? You list 12.5Vf....I'm confused.

2) I thought I'd verify how to hook up in "series". I'd solder the + lead from the switch to the "+" on the first star, then connect the first "-" to the second "+". Continue until the last star's "-" gets connected to the "-" from the switch. Am I correct?

3) Lastly, a question about the Shark/DB...Do I need only one driver for multiple emitters? It seems to me that if I need 4A total for 4 emitters, a single 1A driver will only supply 1/4 my power needs.

Thanks yet again for the warm reception and assistance!

Click to expand...

1164 is shorthand for a Welch Allan #WA1164 bipin incandescent bulb. I don't recall the exact specs, but it runs very bright white off of 8aa cells. I have a hotwire light running this and it's very nice. And no, a new Mag head will not fit an older body without the D in the serial number. I just checked one of my old MagDs, the multi-sink fits but sits pretty high. getting LEDs and reflectors on top might make it too tall to put the facecap back on.

1. My mention of 12.5V, that's an actual measured voltage with a quad-Cree build I did a while back. But it was a lower bin, so had a lower Vf. The 3.7v per LED you mention is just a rough starting figure. The actual voltage drop across an LED will depend on what current you are running it at, what type and bin of LED it is, and also varies slightly from one LED to another even when they have the same specs. The theoretical values for LED Vf and battery voltage are fine for planning a project, but it's best to actually measure voltages and currents, expecially if you are operating near a limit. That's how I blew a $35 LED and $25 driver. I used the theoretical numbers for the battery and LED and thought I was safe. But the actual battery voltage was a little higher and the LED Vf was a little lower than the theoretical numbers and I put the driver into direct drive and blew both. Now I start low and work my way up while doing actual measurements.

2. Well, you know what they say about a picture.......

This is five Q5 Crees mounted on Download's multi-sink and using a Shark driver. The power input leads to the driver come up through the center of sink. As you can see, you were correct in your assumption of how to wire in series.

3. But you just need one driver, not four. The driver boosts the voltage up to around 13V which is high enough to push 1A through all 4 LEDs. In series, voltage adds up and current remains the same through all the LEDS. In parallel, voltage is the same across each LED and the current adds up. In your situation of four LEDs, the Shark driver would put out around 13V at 1A to drive four LEDs in series. If you tried wiring them in parallel, it would put out a little over 3V at 4A (in theory only, in actuality the Shark maxes out at 1A on the output). But the actual current through each LED would vary depending on their individual Vf values. One LED may have a lower Vf and let 1.5A through while the LED next to it may have a higher Vf and only have 0.5A going through it. By wiring in series, you force the same current to flow through all the LEDs. Now if you were to actuallly use four seperate drivers to power each LED individually, each driver would put out a little over 3V at 1A to each LED. But the power drawn from the battery in all three cases would be the same.

Fantastic! Thanks, Don - it's all coming together for me...it just takes a while.

I'll check and see if some optics are shorter than the reflectors, or maybe cut down the reflectors...

As for the emitters; I see you placed the bare emitters on the 'sink. Are they insulated on the back? other than space constraints, why did you not use a star?

I really appreciate anyone's help...stay safe!

DonShock said:

2. Well, you know what they say about a picture.......

This is five Q5 Crees mounted on Download's multi-sink and using a Shark driver. The power input leads to the driver come up through the center of sink. As you can see, you were correct in your assumption of how to wire in series.

Click to expand...

I'm planning on doing a 5 Cree Mag mod using download's heat sink and I was curious about one thing: is there any particular reason for mounting the shark on top? I haven't really planned this out yet, but I was thinking that I would put the shark on the botttom of the other piece of the heat sink and just run the wires through the center hole.

acourvil said:

I'm planning on doing a 5 Cree Mag mod using download's heat sink and I was curious about one thing: is there any particular reason for mounting the shark on top? I haven't really planned this out yet, but I was thinking that I would put the shark on the botttom of the other piece of the heat sink and just run the wires through the center hole.

Click to expand...

Well, in my particular case I am using the Fraen faceted reflectors and with both parts of the multisink it was too tall. I not only had to remove the bottom part but also part of the bottom lip on this part. Besides, if the driver were on the second part of the sink the wires between the driver and LEDs would twist up if you tried to adjust the heatsink height. This way only the power wires stick down through the center and I can add the second part back on and adjust it if I ever needed to.

Makes sense. Thanks.

I have yet another follow-up question for you guys:

I've decided to run with 4 crees on Download's heatsink in an *old* 2D Mag that I'm going to run with 8AA through a Shark. I've seen talk of using an externally mounted potentiometer to control the output, but I'm unsure of the specs I will need.

1) Will I attach the pot between the Shark output and the Crees?

2) What rating do I need to look for in the pot?

Thanks again for everyone's help

grumble....*stupid new hobby taking all my time and energy*...grumble

The pot attaches to the Shark. You need to either remove the trim pot that is standard on the board, or order it with the trim pot already removed, and then add the external pot. The only spec I see is that it should be 20K ohm.

http://theledguy.chainreactionweb.com/product_info.php?cPath=48_49_61&products_id=721

A-ha! Thanks, I overlooked that

If you prefer three fixed levels you can use the Remora UI board with the Shark: http://theledguy.chainreactionweb.com/product_info.php?cPath=48_49_61&products_id=988

Like that you do not need the potentiometer.

BTW: Maglite 2D is one of the most popular hosts for modding - be prepared to find incredible amount of info in CPF (see e.g. my sig line link)! Good luck with your project! :thumbsup:

-N

pretty big project for first go around ...jumping right into the deep end , good luck

Well, if it's worth doing, it's worth over-doing and doing poorly, that's my motto! :naughty:

Thanks, Nereus, I didn't notice your sig until now.

Firecop i think you could use this adjustable height heatsink , so no need to worry about reflector heights i assume

multisink as donshock used
http://candlepowerforums.com/vb/showthread.php?p=2060148#post2060148

Thanks for the heads-up, qip...I ordered that 'sink and am anxiously awaiting its arrival!

I'm starting to re-evaluate my initial plan of using 5 Q4 Crees in this mod. The more I've read, the more I learn that heat production is huge.

Can anyone comment on the Mag's ability to transfer/dissipate that amount of heat? Keep in mind that I tend to work in "warm" environments. (That's what happens when structures burn)

Secondly, am I correct in understanding that the split rail on the Cree Q4 emitter is the positive side and the full length, solid rail is the ground/negative?

This thread is very interesting to me as I too plan a high flux led light for crime scene illumination so I had the same questions as Firecop. I found the 5761 hot wires at almost 900 lumens, just a tad under the 1164 to have great ability to illuminate a scene and good color rendition and about the right amount of light but my longest run is one hour on a modified MagCharger; 1164 will not get that run time because the higher voltage requires the battery space to reach voltage as opposed to Amp/hours . Last scene I was on I could have used 6 hours of high illumination. I went through three sets of batteries with my high flux LED belt light. I wanted a long running tool so I started this thread with the same questions as Firecop and got some different answers the combination of these two threads really helped me!
http://candlepowerforums.com/vb/showthread.php?t=169747
But I never thought about the 5 Q5s. I intend to run 14 AA powerex cells, that will give me over 45 watts, using 4 amps of the Crees, 4x crees at the shark 85% efficiency that should be over 9.5 hours run time. I can get 14 AAs into a 3D. Now Don has me looking at the 5x Q5 set up before I even finish the light. I will use the remora board as that is the easiest way to achieve different light levels, using the board designed to do that with the shark.
Since you are building a light with an adjustable pot. You can turn the level of 5 down to the same output as 4 for both heat and light but still have 5 if you need it. Boy, 1200 lumen led flashlight! Firecop, why did you decide on 4 and not 5 LEDs? What may keep me at the 4 level is the report of overheating of the 5 Crees in one of Downloads posts. The remora has preset levels, medium is about 50% so that does not make sense to run 5 at 50% if you need the light of 4 but you could dial that in or preset it with a multi-level switch and a resistor for 80% of 5. For a heat sink I have a Perfect XR19 Cree Heatsink - D in copper; I can resurface the face if 5 will not align around the pre-cut slots. I am very interested in what you end up with. Thanks.

Northern-it's good to hear from you...

I haven't decided on 5 or 4 emitters, I was hoping to get some feedback from more senior, experienced member about the heat output and the Mag's ability to dissipate that heat.

As for scene lighting, yeah, I'm with you. I've been on scenes where I had to switch out 3 different flashlights. You know what that means, don't you? More flashlights!

Good luck, and I'll keep you posted with my experiences as I mod this light -I'm waiting for Download's heat sink (from China). Stay safe!