First Mag Mod, Got Some Questions

I'm a newbie to modding lights and want to attempt my first mod of a 2 d-cell mag. I've read about 15 different mag mod posts on here (including all of ma_sha1's :bow, but still had a few questions.

Here's a quick breakdown of what I want to use:

Host: 2 D-cell Mag (with the T8 torx screw:shakehead)
LED: SST-90 Red http://www.luminus.com/products/datasheets/PDS-001342_Luminus_SST-90, Product Datasheet.pdf
Cooling: SST-90 Heatsink from BriteLumens http://www.britelumens.com/
Batteries: Four 1.2v sub-C 1500mAh NiCd batteries (Using PVC sleeve) http://www.megabatteries.com/item_details2.asp?id=13725&cat_id=226&uid=1430


I plan to direct drive the LED and hope to get around 600 lumens. My questions are:

1. Is there a better battery option to run 6A to the LED? The forward voltage listed on the spec sheet is 2.2v.
2. Will the stock switch be able to handle 6amps?
3. Has anyone used the Mag reflector made by Phoenix Electroform products?
4. What is the difference, if any, between the stock reflector (LED version) and the rebel SMO reflector?
5. Where can I get a sweet bezel for this thing?

Thanks for any insight you can provide. I'm stoked about doing this build.

So you want to put 4x1.2 volt = 4.8 volts directly into an LED that can handle ~2.2 volts? Unless I am missing something, I can't say that's a good idea. I think you should look into getting a driver (or a roll of 1000 LEDs).

For 6A I think you would want to look up some of the switch mods, best I can say is that 2.8A hasn't melted mine yet.

Lastly: why red?

Think the stock maglite switch is rated at 5 amps, it might melt

JacobJones said:

Think the stock maglite switch is rated at 5 amps, it might melt

Click to expand...

I've used mine safely (though cautiously) at 11A (13A spike).

-DF

yazovyet said:

So you want to put 4x1.2 volt = 4.8 volts directly into an LED that can handle ~2.2 volts? Unless I am missing something, I can't say that's a good idea. I think you should look into getting a driver (or a roll of 1000 LEDs).

For 6A I think you would want to look up some of the switch mods, best I can say is that 2.8A hasn't melted mine yet.

Lastly: why red?

Click to expand...

In one of ma_sha1's mods (link below) he ran four 1.2v batteries to a white SST-90 with a forward voltage listed at 3.87v on the spec sheet. So on that one he was a little less than 1 volt over the spec sheet. His worked well, so I'm thinking that the amps (as long as the voltage isn't more than about 1v over what the spec sheet says) is what really makes the difference here as far as the possibility of cooking the LED.

Ma_sha1 also did a mod to the switch to allow it to handle the 8amps he drove on the mod linked below. So I'm thinking to be safe, I'll need to do the same if I run it for any length of time.

I chose red because I haven't seen anyone else get more than 400 lumens out of a red LED, plus it's something different.


http://www.candlepowerforums.com/vb...-SSR-90-Rebel-Deep-SMO-8Amp-Monster-Dutylight

I would use NI-MH instead of NI-CD. NI-CD cells are pretty outdated and you maybe not get the high current you want.

Uh, you may want to check the Forward Current vs. Forward Voltage graph on page 12 of the datasheet. Reds are notorious for having a VERY narrow usable Vf (I've built several myself). I'd recommend a CC driver as well as NiMH over NiCD or some form of LiMN (IMR) battery setup. But that's just my opinion...

-DF

So you think it will fry my LED? It's not something I want to leave to chance since these LED's are around $40.

I was hoping to not use a driver, but I may need to. The trouble I'm running into is that I can't find any combination of batteries to give me 2.2v and 6A. Can't really find a driver to do that either.

Yeah, I'm thinking that a relatively expensive LED deserves better than DD and/or resistors. Not saying that is can't or shouldn't be done, it's just I've wasted enough time and money on such endeavors myself to NOT recommend them. If you're looking for a driver, TaskLED almost always has a solution. For your situation, I'd look at the H6CC or H6Flex.

-DF

The_bad_Frag said:

I would use NI-MH instead of NI-CD. NI-CD cells are pretty outdated and you maybe not get the high current you want.

Click to expand...

actually nicd most of the time can supply more current than nimh. (unless you got real crappy cells), but in either case, 6a is not the current to be concearned, either cell will supply that much easy, good cell that is.

DFiorentino said:

If you're looking for a driver, TaskLED almost always has a solution. For your situation, I'd look at the H6CC or H6Flex.

-DF

Click to expand...

those drivers are made for white leds, with Vf of 3-3,5. it will fry red led, (most drivers are made for white leds, so theVf is more than red will take) however you need to solder a resistior between the driver and the anode of the led\leds.

alpg88 said:

those drivers are made for white leds, with Vf of 3-3,5. it will fry red led, (most drivers are made for white leds, so theVf is more than red will take) however you need to solder a resistior between the driver and the anode of the led\leds.

Click to expand...

They're CC drivers, not CV. Doesn't matter what the Vf is...

-DF

DFiorentino said:

They're CC drivers, not CV. Doesn't matter what the Vf is...

-DF

Click to expand...

oops, i read it wrong, my fault.

The minimum voltage of either TaskLED driver is 5 volts so 4*NiMH or NiCad isn't enough to keep it in regulation. Also ma_sha1 was using 4/5 Sub-C's that are 33 mm long. Regular Sub-C's like your link in post #1 are 43 mm long. You can't fit 4 of them in a 2D Mag. A pair of 26650's in a 1" PVC sleeve with an H6CC or H6Flex would work.

i didn't link anything, i'm not the op, but good catch, it'll be hard to put 4 sub c in 2d even with tailcap mod. not that he needs 4 cells anyway.
and about driver, you are right, i read the datasheet wrong, my fault.

I didn't realize my post was up long enough before editing, for anyone to read it. Sorry for the confusion. My comment about battery length was intended for the OP.

Based on the feedback, I'm going to go with two 26650 batteries and the H6CC driver.

One other question, how do I regulate the voltage to the LED with the H6CC? I am having trouble calculating the level of resistance I'll need with 7.4V getting cut down to 2.2V. I am driving the red LED at 6A.

seven11 said:

One other question, how do I regulate the voltage to the LED with the H6CC? I am having trouble calculating the level of resistance I'll need with 7.4V getting cut down to 2.2V. I am driving the red LED at 6A.

Click to expand...

The H6CC is a constant current regulator. You don't need resistors to regulate voltage, that's the regulator's function. You don't have to calculate anything. There is a 10 turn on-board pot you use to adjust the current level. You need a DMM with a 10 amp scale wired in series with the LED. Then again, since the board is 6.7 amps max and the red SST-90 is 6.3 amps, that sounds like all you have to do is turn it to max and you're good. The two terminals labeled pot+ & pot- would allow for an external 50K log or audio taper pot to act as a dimmer, but is not necessary.