LED options for 1x26650 IMR direct drive light?

Here is what I'm thinking about building:

1) Single emitter due to beam pattern (no multi-emitter setups).

2) 1x26650 IMR light - host is to be determined but probably for 17mm driver.

3) 17mm driver: FET (hi-modes) and 7135 (Lo mode) driver from Mountain Electronics - so it is direct drive on max.
http://www.mtnelectronics.com/index.php?route=product/product&path=67_117&product_id=480

4) Hi-Drain Clicky from Vinh:
http://skylumen.com/collections/v54-lights/products/fs54-high-drain-forward-clicky

I want maximum lumens output; efficiency is secondary. I am thinking about the latest generation Luminus SST-90 ($50/LED - wow) or CBT-90 but not sure what other options are out there such as OSRAM, etc..

Next is where to buy that LED. Mouser, etc.?

Any help would be much appreciated. Thank you.

Luminus LEDs generally have pretty high Vf. IMR cells aren't quite as good as ICR cells on voltage. I'd expect that the combination of Luminus and IMR might be disappointing.

Unfortunately, when you are talking DD or close to it, every little thing matters. The resistance of your spring, the Vf of the LED, the FET chosen, the switch chosen, the wire size, everything matters. The biggest unknown is the LED, especially if you are talking about Luminus.

DD designs can be really impressive. They can also be impressive failures, with either self-destruction or pitifully low output.

That said, I think with Luminous you are more likely to have disappointing output, while with most other LEDs you are more likely to have short (possibly VERY short) lifetimes.

I recently got the neutral version of this 1x26650 light from Mountain Electronics. http://www.mtnelectronics.com/index.php?route=product/product&path=80&product_id=652

It has a lot of mass and should be easily modded, too. M.E. is also going to have a host-only version of this at some point in the near future. The stock driver is only pushing 3 amps to the LED, so there is room for a lot more drive with proper heatsinking. I don't know if the stock LED in this light is on a copper MCPCB or not, as I haven't opened it up yet. I plan on modding it to direct drive at some point and swapping the LED to a warmer XP-L HI on a Notigon board.

DIWdiver said:

Luminus LEDs generally have pretty high Vf. IMR cells aren't quite as good as ICR cells on voltage. I'd expect that the combination of Luminus and IMR might be disappointing.

Unfortunately, when you are talking DD or close to it, every little thing matters. The resistance of your spring, the Vf of the LED, the FET chosen, the switch chosen, the wire size, everything matters. The biggest unknown is the LED, especially if you are talking about Luminus.

DD designs can be really impressive. They can also be impressive failures, with either self-destruction or pitifully low output.

That said, I think with Luminous you are more likely to have disappointing output, while with most other LEDs you are more likely to have short (possibly VERY short) lifetimes.

Click to expand...

Thank you for the info.

1) Do you suggest another driver for the SST-90? If so, which one?
2) Do you suggest another LED?

Thank you.

Mr. Tone said:

I recently got the neutral version of this 1x26650 light from Mountain Electronics. http://www.mtnelectronics.com/index.php?route=product/product&path=80&product_id=652

It has a lot of mass and should be easily modded, too. M.E. is also going to have a host-only version of this at some point in the near future. The stock driver is only pushing 3 amps to the LED, so there is room for a lot more drive with proper heatsinking. I don't know if the stock LED in this light is on a copper MCPCB or not, as I haven't opened it up yet. I plan on modding it to direct drive at some point and swapping the LED to a warmer XP-L HI on a Notigon board.

Click to expand...

Thank you for the suggestion. I like the host but I thought I read somewhere it weighed about 1.3 pounds (without a battery) which is heavy. Now with the battery...

First, I want to correct a mistake I made in my earlier post in this thread. IMR cells have very similar discharge curves to ICR cells, except that some of them can go to substantially higher current (but please check the ratings on the specific cell you are using before loading it heavily). I imagine that's why you specified IMR. I was thinking about IFR cells, which have lower voltages.

You didn't say what your target drive current is, but since you picked the SST-90 and a 26650 IMR cell, I'm guessing you were aiming for around 9A. I'll answer based on this assumption.

Now, for you questions:
1. Not just a different driver, but a different battery as well. With Luminous LEDs, you're generally going to be best with two or three cells in series and a buck type driver. You want max output, so you're going to be pushing the emitter hard. I checked the latest data sheet, and the typical Vf at 9A is almost 3.9V, so a brand new, quality, fully charged cell with direct connection and absolutely minimal extra resistance could put 9A in the LED momentarily. But the cell voltage, and thus the current, and thus the output would immediately start dropping. If you had any external resistance, even ten milliohms or so, you'd never reach 9A at all. With two cells and a Der Wichtel driver, you could run 9A from full charge to dead flat.

2. The top bin SST-90 puts out about 2700 lm at 9A. I'm not aware of anything that can come close to that in a single die. If you can run two cells, a Cree XHP-70 can put out over 4000 lm with less input power. This means it would run much cooler, allowing you to run at full power longer before having to shut down because of high temperatures. But the XH-P70 is 4 dies in a single emitter. You said single emitter. I wonder if you meant single die? If you are dead set on a single cell or a single die, you probably aren't going to top the SST-90 for sheer lumens.

2A. If you are looking to make a thrower, you don't want lumens, you want candellas. Others may know better, but I think the current best thrower is the Cree XP-L Hi.

Don't be so quick to dismiss Mr Tone's suggestion. You are looking to build a light that will generate a lot of heat. At the power levels where an SST-90 is the best choice, you will not be able to run a small, light weight hand-held light continuously for more than a minute at a time, give or take, without overheating the LED and possibly other parts as well. A light with some mass to it will (if properly built) extend this time substantially.

I have a Fenix PD40 with a MT-G2 LED and use this as my first choice of a single battery dedicated flashlight. My EDC is a ZebraLight SC600 Mk 3.

Rethinking this project based on what you all have posted, I am now inclined to wait until a DIY boost driver becomes available to run the XHP-70 on one cell. Although there are several manufacturers who have boost drivers (Zebralight, Fenix, Shadow, DQG, Acebeam come to mind), there is no stand-alone driver for a DIY light project that is currently available to run a high voltage XHP or MT-G2 LED on a single battery. I assume the wait won't be too much longer...