Help modifying an old 3C maglite w/ 3 x CREE/Rebel

[Garbanzo]

I know a little bit about electronics (ie. I took physics in college ) and I am a decent solderer, so I figured why not play around.

This is what I am currently looking at

http://www.dealextreme.com/details.dx/sku.1916
http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3256
and either 3 x Q5 emitters or 3 x rebel 100 emitters

So my question is, would these work with a 3C maglite if the bulbs are wired in parallel? This should give all three regulators a 4.5v source and at an assumed 8000mah for an alkaline C, I would get about 6-8 hours on max. Correct?

If I am completely wrong, I blame it on a bad physics professor.

 

[Gunner12]

You shouldn't wire the LEDs in parallel unless you have tested them to have identical Vf. If not, one will draw more power then another. In theory they should work but in real life, each LED has a slightly different Vf so with the same voltage, they will draw a different current.

Don't forget a good heatsink so the LEDs don't fry.

How's this. 3 Cree XR-E Q5, whatever optic you like that fits, these drivers(One for each LED, do whatever you want with the extra driver), and a maglite with 3-6 cells. Less runtime but much more output(700 mA or more VS 400 mA).

I'm guessing you have used a Cree/Seoul/Rebel light before.

:welcome:

 

[Garbanzo]

You shouldn't wire the LEDs in parallel unless you have tested them to have identical Vf. If not, one will draw more power then another. In theory they should work but in real life, each LED has a slightly different Vf so with the same voltage, they will draw a different current.

Don't forget a good heatsink so the LEDs don't fry.

How's this. 3 Cree XR-E Q5, whatever optic you like that fits, these drivers(One for each LED, do whatever you want with the extra driver), and a maglite with 3-6 cells. Less runtime but much more output(700 mA or more VS 400 mA).

I'm guessing you have used a Cree/Seoul/Rebel light before.

:welcome:

Ya, I have a fenix P2D and I just bought an ultrafire EMR1, which I am still waiting to arrive. This is my first experience with out of country products and it is so cheap that I figured it would be a fun little project even if it doesn't go perfectly. I have never modified CREE stuff though, so this will be new to me.

If I don't run them in series, won't each driver only get 1.5v (assuming 3x1.5v C batteries) and in turn not be enough voltage for that driver since it is regulated?

If running them in series is ok, would using those 1200ma drivers be too much for the Q5s? I just assumed that they will actually be a little lower than the rated amperage and therefore probably be around 1000ma.

Also, I thought about the heatsink, but that is the only thing I haven't figured out yet. I was looking through some of the more complex custom flashlights, but I am lacking a CNC machine for any seriously cool stuff, what do most people use for heatsinks in maglite mods?

Oh and thanks for the help.

 

[Garbanzo]

I read something about aluminum foil and heat sink grease, but that doesn't exactly seem like the best solution for a heat sink. Any other options for someone without a lathe?

 

[eidolen]

Hi Garbanzo,
You actually have quite a few options available that haven't been covered yet.

First you should decide if you will be using bare emitters or some sort of star board. This will determine what type of heat-sink you need. You can purchase both types at the Sandwich Shoppe as well as some sellers here on the forums. Running 3 Crees will generate quite a bit of heat and will be an expensive experiment if you don't invest in an adequate thermal solution first. Don't forget about quality thermal paste or epoxy to transfer the heat to the heat-sink. Both can be found here.

http://theledguy.chainreactionweb.com/index.php?cPath=48_56_73


As for the electronics I'm not sure I follow what you were saying. You definitely don't want to run the LEDs in parallel but you should be able to run the converters in parallel with a single LED to each board. Make sure whatever board you go with that it accepts down to 3.6V so you can use NiMH which will improve performance and cost in the long run if you will use the light often. Using Lithium-Ion batteries vastly improves your converter options but is also very dangerous if you are not aware of the safety precautions. Not really a good idea for a first build and quite expensive but something to consider in future projects.

The biggest factor in how much current you can run to the emitters would be how well they are heat-sinked and what kind of lifespan you want from them as they are directly linked. You can find many many threads on the subject I'm sure but I wouldn't recommend 1200ma unless you are prepared for a short lifespan or spend some time reading up on it.

As this is your first mod I would also recommend going with Cree over Rebel LEDs. Rebels are much smaller and from what I've read, more difficult to work with where Crees are more mainstream and you will find a lot more options as far as optics and heat-sinks. It's great that you are asking questions and getting help before you start and I hope you find what you need to start your build. If done right it is a gratifying experience, but can be expensive and frustrating if you're not prepared. I can't stress enough to search and read these forums often. I am adding some of my favorite links that might be of use to your cause. Have more links on other computer and will try to add some more. Best of luck!

Eidolen

a 3C Mag build:
http://www.candlepowerforums.com/vb/showthread.php?t=144921

Very nice converters and tons of good info:
http://www.taskled.com/

Lots of DIY flashlight parts:
https://www.lighthound.com/

Quad Mag 2C (Has list of parts w/links further down page)
http://www.candlepowerforums.com/vb/showthread.php?t=167976

 

[Garbanzo]

Hi Garbanzo,
You actually have quite a few options available that haven't been covered yet.

First you should decide if you will be using bare emitters or some sort of star board. This will determine what type of heat-sink you need. You can purchase both types at the Sandwich Shoppe as well as some sellers here on the forums. Running 3 Crees will generate quite a bit of heat and will be an expensive experiment if you don't invest in an adequate thermal solution first. Don't forget about quality thermal paste or epoxy to transfer the heat to the heat-sink. Both can be found here.

http://theledguy.chainreactionweb.com/index.php?cPath=48_56_73


As for the electronics I'm not sure I follow what you were saying. You definitely don't want to run the LEDs in parallel but you should be able to run the converters in parallel with a single LED to each board. Make sure whatever board you go with that it accepts down to 3.6V so you can use NiMH which will improve performance and cost in the long run if you will use the light often. Using Lithium-Ion batteries vastly improves your converter options but is also very dangerous if you are not aware of the safety precautions. Not really a good idea for a first build and quite expensive but something to consider in future projects.

The biggest factor in how much current you can run to the emitters would be how well they are heat-sinked and what kind of lifespan you want from them as they are directly linked. You can find many many threads on the subject I'm sure but I wouldn't recommend 1200ma unless you are prepared for a short lifespan or spend some time reading up on it.

As this is your first mod I would also recommend going with Cree over Rebel LEDs. Rebels are much smaller and from what I've read, more difficult to work with where Crees are more mainstream and you will find a lot more options as far as optics and heat-sinks. It's great that you are asking questions and getting help before you start and I hope you find what you need to start your build. If done right it is a gratifying experience, but can be expensive and frustrating if you're not prepared. I can't stress enough to search and read these forums often. I am adding some of my favorite links that might be of use to your cause. Have more links on other computer and will try to add some more. Best of luck!

Eidolen

a 3C Mag build:
http://www.candlepowerforums.com/vb/showthread.php?t=144921

Very nice converters and tons of good info:
http://www.taskled.com/

Lots of DIY flashlight parts:
https://www.lighthound.com/

Quad Mag 2C (Has list of parts w/links further down page)
http://www.candlepowerforums.com/vb/showthread.php?t=167976

That is what I originally meant, sorry for not clarifying. I was going to run the drivers in parallel. I figured I would use starboards just because I have read that it is difficult to solder on the emitters themselves without damaging them.

Thanks for the info on the 1200ma drivers, I think I will go with the 800s instead just for safety.

And thanks for all the links, I will read up and report back once I get some more info.