Need help with LED electronics!!!!

Greebe

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So I want to build a 1AA light with a solid body. Kind of like the Fenix P1D CE Premium Q5.

I can buy the LxD series reflector from fenix-store.com. I can machine the body and head from 6061.

My question is about the electronics. I need help to understand what I need to build the LED assembly. Do I only need the LED, Driver and some sort of switch? How do I determine which ones to buy for a single AA set up that will give a one level output and good run time at around maybe 50-60 lumens? Or maybe a two level output of around 10-20 lumens and 60 or so.

I really like the looks of the Fenix LD10+ but it is way more complicated than I want. I want something simple without all the crazy functions. I do not need strobes, SOS, and 100 different levels of output. Plus I want to make one of my own design.

Any help would be greatly appreciated.

Thank
Greebe
 

foxtrot824

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I look forward to seeing pictures of the finished product! As far as drivers go you will need some type of driver to step up the voltage to the LED if you are running of an AA battery. A boost type circuit would be the best bet if you plan on using a regular AA or rechargeable NiMh battery (1.2v-15v) . A direct drive setup could be done if using a 14500 AA Lion battery but this would most likely result in something much brighter than 60 lumens and might still need a resistor in place to prevent the input voltage from exceeding about 3.6v (a fully charged Lithium Ion battery can be as high as 4.2 volts, protected cells stay closer to 3.6-3.7).

I would look at the sandwich shoppe for drivers, right off the bat I would look at something like this guy. It provides 300mA of regulated current to the LED. Driving a XR-E Q5 at that current might get you close to your targeted output.

The switch style depends on your preference. A twisty might be the easiest route if you are machining your own body. This style would just use the threads to tighten or loosen the contact on the battery terminals to complete the circuit.

Good luck with your project!
 

Gunner12

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The Nitecore EZ AA could fit your requirements, but what's the fun in making a prebuilt light ;)

If you want a single mode and cheap driver, here's one for you. With a Q5 or R2 bin Cree LED you should be able yo get the output you want.

As for the bezel, looking at how other lights are put together might be a good start. Most lights have an internally threaded bezel. The o-ring goes in first, then the glass window, then the reflector, then the pill. The pill is a metal part that holds the LED and driver. It helps transfer the heat from the LED to the body of the light and also to hold the driver. If you look at threads with disassembled lights, you might have a better picture of what I'm talking about. This thread has good pictures.
 

Greebe

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Thanks for the replies.

FT824—

I looked at the driver you posted but it said that the minimum input was 1.6V. I am hoping to use rechargeable Duracell AA's that are 1.2V @ 2650mAh. Would that driver work for that?

I found this driver on that same site, and it says the input voltage can be as low as 0.9V, but the output is 700mA.

Gunner—

I looked at the link you supplied and it was out of stock like a lot of the parts from that company.

I did find this 5-Mode driver that is rated for a 0.9V-4.5V input. It has a memory so I could set it for the mid mode @350mA and leave it there I guess. This was one of the only ones that was in stock for the low voltages.

So you guys think that I should be in the 300-400mA range to get around 60 Lumens? How long could I expect for run times with a regular AA battery or a Duracell 1.2V 2650mAh at that output?

Also there didn't seem to be a lot of Q5 LED's in stock either. I found this LED. Would it work with one of the above drivers?

Thanks again
Greebe
 

TorchBoy

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Re: Need help with LED electronics!

Also I found this reflector. Would that work with the LED that I posted above?
It'll "work", but the question is how well? I'm curious to know too, because I have some of those reflectors but haven't got any XP-Es yet. It might be just a matter of positioning the LED in the right place for a desirable beam shape want. I think the XP-E sits a bit lower than the XR-E that I've used that reflector with though.

Driver suggestions. Drivers don't care what sort or brand of white LED they power so these things will work with that LED just fine.

BTW, Cutter sells 10 mm square optics that are designed to fit on the 10 mm square boards they sell their XP-Gs (and probably XP-Es) on. If you're happy with all the machining you could turn the optic round and get a 10 mm round LED board instead.
 

TorchBoy

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Re: Need help with LED electronics!

Drivers don't care what sort or brand of white LED they power so these things will work with that LED just fine.
OK, I know that's a generalisation. A Cree MC-E with the dice in series in an exception, Luxeon V is another.
 

Gunner12

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Re: Need help with LED electronics!

Hummm, the driver was in stock when I linked to it.

Q5 is a flux bin, not a model number. It's an output rating for the LED. XR-E, XP-E, MC-E though are model numbers of some Cree LEDs.

Drivers don't really care about what brand or type of LED it is powering, as long as as the LED has the same Vf. Dealextreme is just a dealer, they don't really make anything. The driver is made by another company.

You should be able to get over, 60 lumen out the front with 300-400 mA with a Q5 flux bin or above.

As for the reflector, as long as the LED is at the focal point, you should get a good beam.
 

gcbryan

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Thanks for the replies.

FT824—

I looked at the driver you posted but it said that the minimum input was 1.6V. I am hoping to use rechargeable Duracell AA's that are 1.2V @ 2650mAh. Would that driver work for that?

I found this driver on that same site, and it says the input voltage can be as low as 0.9V, but the output is 700mA.

Gunner—

I looked at the link you supplied and it was out of stock like a lot of the parts from that company.

I did find this 5-Mode driver that is rated for a 0.9V-4.5V input. It has a memory so I could set it for the mid mode @350mA and leave it there I guess. This was one of the only ones that was in stock for the low voltages.

So you guys think that I should be in the 300-400mA range to get around 60 Lumens? How long could I expect for run times with a regular AA battery or a Duracell 1.2V 2650mAh at that output?

Also there didn't seem to be a lot of Q5 LED's in stock either. I found this LED. Would it work with one of the above drivers?

Thanks again
Greebe

You should get about 2-2 1/2 hours at 350mA.
 

Justin Case

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Don't confuse a driver's advertised minimum operating voltage with the voltage needed for fully regulated output. You need to know what output current the driver will give you at that minimum operating voltage, which is most likely a turn-on voltage. So for many drivers, all you will get is a moonglow output at the min operating voltage.

You might be in luck, however with the MAX1674 boost IC used in The Shoppe's Madmax Plus driver. At 1.2V input, the IC is rated to deliver about 150mA, which is basically what you need to get about 50-60 lumens out from a Cree XR-E Q5. So, the Madmax Plus might work. I would ping Wayne on The Sandwich Shoppe's subforum here on CPF and ask him specifically if the Madmax Plus will work with 1xAA and give you the drive current needed to get the lumens you desire from an XR-E Q5 or R2. Or if you can use it, possibly one of the new Cree XP-G R4 or R5 LEDs.

For me, I would get a quality product with good technical support from an outfit like The Sandwich Shoppe over these mystery drivers from DX or KD. At $8, the MM+ isn't overly expensive.

Here is a Cree XR-E Q5 on a 14mm base. Price is higher than the XP-E that you linked. The XP-E will probably have a lower Vf as well. If it works in the reflector or optic that you plan to use, then I'd go with the XP-E. Otherwise, the XR-E is tried and true.
 
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TorchBoy

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Can the XR-E cope with heat a little better than the XP-E? And I got three of those 14 mm XR-Es. They had quite a low Vf, from memory around 3.3-3.4 V at 1 amp.
 

Justin Case

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On a packaging and die size basis alone, I would think that the XR-E has the advantage. Specs-wise, the XR-E also is slightly better than the XP-E wrt thermal resistance between the junction and solder point.

In the real world? In the white LED lumen testing by jtr1962, the XP-E was taken out to 2.5A IIRC. He took an XR-E Q5 to 2A and an R2 to 2.8A. All had lots of output. The XP-E seems to run out of steam more than the XR-Es at the higher amps, but jtr's heat sinking for the XP-E also seems not as good as for the XR-E R2, at least.

In any case, I would venture a guess that driving an XR-E or XP-E to "practical drive currents" is very doable as long as you have good heat sinking. Not really a big surprise.

Even though the XP-E seems to be spec'ed at a max of 700mA drive current, I know that Moddoo overdrives his triple XP-E P60 drop-ins at 3A (1000mA per XP-E) and the triples seem to be doing ok (granted, I don't think anyone has actually done any quantitative testing of what "doing ok" means -- e.g., white point stability, lumens maintenance, etc; but the drop-ins seem to be performing reliably in terms of end user perception).

I measured about 3.2V at 700mA for my parallel-wired triple XP-E R2. jtr1962's measurements at 700mA were in the 3.5V-3.6V range for the XR-E R2s he tested, and 3.4V for the Q5 bin. If you got 3.3V-3.4V at 1A, you're doing good. I need to do a measurement on my triple XP-G R5.

For the low drive currents considered here in this thread, I doubt that heat is an issue for XR-Es, XP-Es, XP-Gs, whatever. Not at 150mA.
 
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