Electronics, Lighting, & Gadgets - DIY - LED to replace HID?

Hello! I was riding in to work today and my light turned off. I don't know why, and I kind of don't care. It's an excuse for me to get a new light! ;) :D

Now, what to make? I have a 13W Trailtech HID setup courtesy of Batteryspace with a rechargeable Li-ion 4800 mAh battery, and it is pretty close to 40W halogen brightness with ~4hr runtime. I want to go with an LED setup that is dimmable. In fact I want even more light than the HID, but also the ability to run it lower when I don't need as much light. My research has pushed me in the direction of:

XR-E Mounted on Triple PCB for MR16: Q5 3-LED
some sort of buckpuck to control dimming and flashing?
waterproof casing that doubles as a heatsink
handlebar mount
waterproof switch
target lumens = 700+

Does this sound like I'm on the right track to get a single light that can produce that many lumens? The MR16 setup is available with triple Q5 Cree emitters, and apparently is the latest and greatest. I can get aluminum tubing and plate in any dimensions I need, but I don't have access to a lathe or machining tools beyond a dremel and hacksaw. I will learn how to solder properly. One thing I haven't seen is how to put a weatherproof lens/cover on the front so that it can be replaced easily. Is a flexible silicone caulk the only way? I keep thinking a screw-on clear cap would work, but I haven't seen anything appropriate.

I have done searches here and elsewhere, resulting in my choice of LED format and dimmer. I like the square aluminum tubing that one guy used (http://myfwyc.org/bikeled/DIY_LED_Bike_Lighting_Guide.html) to create a handlebar/head light using separate single emitters with lenses, and I think I can adapt that design. However, I'm really unsure on the electronics assembly. Is the MR16 format worthwhile, or should I just get individual LEDs?

All suggestions, links, etc. are appreciated!

"Some sort of buckpuck to control dimming and flashing" has got to be the bflex from www.taskled.com
You need to know how to use a soldering iron but thats not too hard.
www.cutter.com.au now offer mr11 kits with 3 XR-Es, lenses and bflex driver.

Silicon is good stuff, if you screw things up you can usually clean it off and start again.

Check out the "total geekiness" thread here and also the bike page over on candlepowerforums

Weird. My 13 watt Trailtech HID went off partway into the commute this morning too but
it was because the battery discharged. Is charging now.

Right now we're just short of the lumens we want in an LED format. The Trinewt is 500
lumens (13W Trailtech HID is about 720-725 I'm guessing since they reported 30% brighter
than the 10W Trailtech HID which was 550) and there's a new light called a TridenX by
Cygolite that purports to be HID quality brightness.

So the only way you're going to get to the 700 lumens area is a custom design with multiple
bright LEDs.

The other bright LED light, of course, is the Lupine Betty but that thing is seriously spendy,
as in "new bike spendy".

The Betty is over a grand for 1400 lumens. :eek: It's a bit more than I need, methinks. I still can't get my light to work, but the battery takes a charge. The problem is likely in the wiring, but I'll have to dig out my voltmeter to check.

Anyway, I'll create something similar to the setup from http://myfwyc.org/bikeled/DIY_LED_Bike_Lighting_Guide.html but use Cree XR-E Q5 LEDs and a bflex in a 2x2 array. The whole light should be a 2" cube with a wire and switch out the back. I'm thinking two soft spots plus two wide angles, or some combination of narrow and wide. At 700mA, I should get something on the high side of 600 lumen.