Help identifying parts for homemade light

[jabe1]

I wouldn't worry about the LED having a dome or not. Try to go with an XM-L, you'll get a lot of lumens for your power level, and a good sized hotspot.
The dome on the LED acts as a primary lens to help focus the beam. If you want more flood and less throw, keep the dome, and use an orange peel, or stipples reflector.

I would be interested in seeing what the old LED was.

 

[thumpergirl]

I wouldn't worry about the LED having a dome or not. Try to go with an XM-L, you'll get a lot of lumens for your power level, and a good sized hotspot.

How will the XM-L[2] compare to the XP-G[2]? Both state a 'larger' die size in the flashlight wiki, http://flashlightwiki.com/ but I'm not sure which is larger and will give me more 'flood'. Probably the best way to find out is to order both and try them out. I've got an XP-G2 R5 on the way

Regarding the XP-G2 R5, i think the R5 bin means it will be a 'cool white', although i want more of a nuetral. But the cool always puts out more lumens. Is that a correct statement?

I've also discovered that it's not all about the lumens. The color, flood, throw all add up. I think the best way to figure it out is to put together several lights and see which one works / looks the best. So, that's my plan. You should see my kitchen table. It looks like a science experiment. I really don't have time for this, but it's so fun. I digress...

Before I really understood just how much difference the emitter actually makes, I bought a couple of cheapie parts online and assembled them. I wasn't even sure what I was dealing with. Q5. It sounded good. I pulled out the drivers in both lights and replaced them with the MR16 bucks. Both lights worked. Both lights looked almost exactly the same, except one had a blueish tint (probably higher lumen output but I don't have a way of measuring it) and the other a nicer more natural tint (preferable for me). Upon farther inspection, I believe they are both old XR-E emitters (you can tell by the distinctive metal ring around the emitters), problably both outputting in the vicinity of 110 lumens. It looks like the XM-L2 or XP-G2 will put out about 150 lumens at 350mA. That should make a difference on the river. Also, I'm guessing that both of those have a larger die than the XR-E. At least the XM-L does according to both of you guys.

What bin would correspond to 'neutral' (~5000K) for the XM-L2 and xp-G2?

I would be interested in seeing what the old LED was.

Upon closer look, it looks like an XM-L, but I'm certainly no expert in identifying these. I can't visually match it to any other emitter on the flashlight wiki.

 

[thumpergirl]

Regarding reflectors and flood. I've heard some people say that it's the die. I've heard others say it's not the die at all, that it's the reflector. My guess is that they are both involved, starting with the die.

That said, are all reflectors created equal? I know there is smooth, textured, and orange peel. (Maybe textured and orange peel are the same, not entirely sure but I thought there was something inbetween smooth and orange peel EDIT: I see you mention stipple above, that must be what I was thinking of...). It seems like the actual shape of the reflector would make a difference in the throw. I haven't seen a lot of different intel out there on reflectors, and there don't seem to be a host of choices on websites when purchasing.

In addition to a decent flood, I'm looking for a wider viewing angle. I will need to know what's to my left and and my right on the river at night, in order to avoid obstacles as they arise...

The reflector in the picture above is actually a smooth reflector, but the light had decent flood. I know it doesn't look smooth but it got salt water in it and is corroded. It is smooth to the touch.

If there's a particular reflector that anyone recommends for a good combination of flood and throw, I'd love to hear about it. And if there are options regarding depth, and for lack of a better work, 'scoop', I'd like to hear about that too.

 

[thumpergirl]

The dome helps get more light out of the LED. Without it, some light would reflect off the inside of the flat surface of the LED and be retuned into the die. All the LEDs you should be looking at will have a dome.

The smooth reflector will create more of a hotspot. A textured or 'orange peel' or OP reflector will give a more diffuse beam.

Also, a bigger die will give a larger hotspot, so the XML would help a bit with that. Just not a lot.

If you want to avoid the harsh bluish light, you want an LED with a color temp below 5000K or so. 5000 is kind of neutral, 4000K is getting warm and a 'warm' white is 3000K or less. IIRC the XML is available in 2700-8000K or so.

Great info, thanks DIW. I've ordered a
Cree XM-L2 T5-5D 260LM 4000-4300K LED Emitter
to see what the output looks like on that.

The clock is ticking... I should be out training today but I almost split my hull in two on a training run yesterday, so today is gadget and repair day.

Thanks again for all the help on here.

 

[DIWdiver]

Bummer about the hull! Sounds like you can fix it though. Good luck.

If you want the greatest possible throw, you would really want all your light to come from a single point. A spherical lens or a parabolic reflector could focus this into a perfectly collimated beam (all light rays travelling perfectly parallel to each other), which would have theoretically infinite throw. Add a second point, and no matter how close to the first, no optic could focus both points into a single perfectly collimated beam.

When you have an LED, it has a nearly infinite number of point sources spread over an area. So you'll never be able to get a perfectly collimated beam. But the smaller the LED, the better beam is possible. Also, the bigger the optic, the better is possible. That's why people going for throw talk about die size so much.

But if you aren't attempting the tightest possible beam (read: greatest throw), then the die size becomes unimportant pretty quickly.

Even discounting the surface finish, all reflectors are not created equal. They are all parabolic, but they differ in scale and aspect ratio (these are my terms, so don't expect to find them in other discussions). The scale is related to how pointy the theoretical tip of the parabola is, which also affects the 'slope' of the sides. The aspect ratio is the ratio of the depth to the diameter. Technically it's the depth from the rim to the focal point, which can be slightly inside or slightly outside the actual part, and it's the inside diameter at the front edge. Practically, it's the depth from the rim to the LED surface, which can be slightly in front of or behind the focal point.

Obviously, with a wide, shallow reflector (low aspect ratio) much of the light will escape without ever hitting the reflector. This is the 'spill'. With a deep, narrow reflector (high aspect ratio), much more of the light will be gathered by the reflector and focused into the 'hotspot'.

Since you are looking at P6 reflectors, the diameter and depth are pretty nearly fixed. There's not much a manufacturer can do with either the scale or the aspect ratio before the reflector becomes impossible to fit in a P6. But there will be small variations. Also, the location of the LED w/r/t the focal point will have an impact on what the beam looks like. In most dropins, this is something you don't have easy control over. Some you can unscrew a little, but if you unscrew them much, either they come apart or they won't fit in the light.

So for the most part, reflectors you will be looking at are all pretty similar, except for degree of texture. BTW - OP, orange peel, stipple, texture, are all the same thing. Smooth or SMO is the opposite.

 

[jabe1]

You should like the results you'll get with the XM-L2 neutral in an OP reflector. The spill will be brighter, allowing you to see more to the sides.

 

[Microa]

Hi thumpergirl, if you have time, you should have a look of this video which shows how to modify a flash light. http://budgetlightforum.com/node/29612#node-29612

 

[thumpergirl]

Great videos, Microa. Thanks for the heads up. Watched them all and they were very informative and helpful.

Edited: I asked a question here, but it was already answered by DIW in an earlier post in this thread. Some of this stuff I have read several times for it to sink in!!!!

 

[DIWdiver]

A 1x3W driver would have an output of around 1000 mA. That's what makes it 3W: 1000 mA * 3V = 3000 mW = 3W.

A 3x1W driver would have an output of around 300 mA, and still 3W total output because the voltage of 3 LEDs is more like 9-10V: 300 mA * 10V = 3000 mW = 3W.

Keep in mind that a "3W" driver is only an approximation. It's more like a "3W class driver". We talk about 1W, 3W, 5W, 10W drivers like car people talk about compact, mid-sized, and full-sized cars. In both cases, the devil is in the details.

So the 1000 mA output would give you roughly 3 times the light output. To your eye, this will look like a lot less than 3 times the brightness. It will also be three times the load on the battery, which will drain it 3 times as fast.

 

[thumpergirl]

Your battery pack is about 45 Watt hours

Can you tell me how you calculated that?

 

[thumpergirl]

Update:

Got plenty of parts in. Went overboard on parts. Have parts coming in probably for the next month or so, and will have probably 10 flashlights built. I wanted to try all sorts of different configurations. This might turn out to be another 'problem' (ahem, obsession) for me.

Ordered a Solarforce L2 host but was shipped a Uniqefire L2. Quality seems to be about the same so no big deal there, and would take too much time to remedy the situation. Picked up an XP-G2 emitter on a 10mm PCB (needed a 16mm but they didn't have it) and an empty drop-in. Used Arctic Silver thermal adhesive to adhere the PCB to the pill. I'm not the best at soldering the lead wires to the PCB yet, but hopefully that will improve with time. Maybe a different tip on the iron will help with that.

So, hooked all that up with the MR16 300mA driver, with the cable gland and 2 pin connector. Used some E6000 to waterproof all the joints. Put it on a fresh pack of 10 AA alkaline batteries for a test (lithiums are just too expensive to waste on a 'test'). So far the light has been running for 20 hours, nonstop, with no heat issues and seems to be outputting the same amount of light. It will be interesting to see how long it will run before dying.

I am assuming that the lumen output will not change as the battery pack drains, because the MR16 driver will continue to deliver 300mA until it can no longer do that. I'm expecting the light to shut off abruptly, rather than beginning to dim before it goes out. Can anyone shed some light on that? (pun intended)

I have also hooked up an XML T6 emitter into a Solarforce L2 host. Can't remember the color bin but it seems much warmer the the color bin on the XP-G2. The XML T6 was a drop-in that I disassembled and removed the driver, then added the MR16. This was a little more expensive, but nice because the lead wires were already on the PCB, which was the right size and already epoxied to the pill. It also comes with the correct sized thermal gasket. It's quicker and less hassle to put together, but probably costs about an extra $10 based on where I got the parts.

Next I will try with a 600mA driver and see what kind of output I can get with that, and how long it will last. I would guess based on what DIW has posted on this thread, that the battery life would be about half, and the lumens would about double. I might be able to pull that off and bring 2 battery packs with me to the race. More testing...

I should be getting around 140 lumens from the XML but I don't have a way to test/confirm that yet. I've got some XM-L2's on the way, so it will be interesting to see the differences there, provided I can find an affordable way to accurately test lumen output. Hint: Smartphone apps don't work well.


Waiting for thermal gaskets to be shipped from overseas. Is there something around the house that would suffice in the interim? Need to cover the lead wires from the emitter board so they don't make contact with the reflector. Wondering if I can use a hole punch to make some out of electrical tape.

Pics coming, and I'll report on the final run time when the light finally goes out.

 

[thumpergirl]

Can you tell me how you calculated that?

Nevermind. DIW, it turns out you've answered a lot of my questions before I even knew they were questions I'd have. From another thread where you stated:

"But an Energizer Ultimate Lithium cell is around 3000 mAH, at 1.5V, so that's a total of 4.5 W-H (that's Watt-Hours). Ten of them would give you 45 W-H."

 

[DIWdiver]

Well, it (probably) won't wink out like turning off the switch, but it will go from full on to nearly nothing pretty quickly. Or it might start flickering.

The XM-L2 will be a bit brighter than the XM-L, but it may not be detectable by eye unless you have them running side by side.

Measuring lumen output requires an integrating sphere. You can get a lux meter on the internet pretty cheap, but that's not the same thing. Lumens are the total light output, lux (or candlepower) is brightness at a single point. Change the focus and you change the brightness, but not the lumens (at least not much).

 

[thumpergirl]

Replaced the driver last night in one of the lights. Much more light. The host gets a little hot now, but not too bad. Not sure I need that much light, but I'll take them both out on the river this weekend on a night paddle and see how much difference it makes in a 'real case' environment, versus a bright spot on a white wall.

On one of my first tests a couple of weeks ago, I got a drop-in with a voltage rating that allowed for my battery pack to run the light without any driver modification. The host got so hot after a while I could no longer pick it up.

The XP-G2 neutral is still running on the original 10 alkaline AA battery pack. I'm now at 32 hours and it's still usable. (easy to say when you're not avoiding river obstacles at 5mph)

Regarding measuring lumen output, there was a great article I read a week or so ago on the budget light forum about making your own integrating sphere. When the race is over and I have more time, I may try to make that a project so I can really tell the end result of all of these different components.