advice on build components for DIY trail light

[neex]

Hi there,

I have never done anything like this before but I am looking to build a functional LED trail light that I can be proud of as a backup for my MOAB I currently use. I'd hate to have the bulb blow on a midnight DH run.
Anyway, I have put the cart before the horse and placed a component order already. Please advise as to whether or not this seems to be a functional and possible build.


Name Code Qty Each Options
---------------------------------------------------------------------
Cree XR-E Q4 Star LED CREEXRE-W100 4
3023-D-E-1000P Wired 03023-D-E-1000P 1
BuckPuck, 1000mA Output,
DC Powered w/
Potentiometer
Spot Base Module - 6&deg L2-OPTX-1-006 4

I have done a fair bit of research and it would seem that the buckpuck can be run with anywhere between5-30VDC which gives me flexibility to switch between a few power packs. I had read of some folks driving the XR-E Q4s at 1400mA so I assume capping the output at 1000mA will be sufficient. I wanted to go with the trim pot so that I could dial down the light at the trailhead, on fireroads, etc.

The optics were a bit of a gamble as there wasn't much available where I placed this order (that I knew of anyway). I wanted a pretty focused spot anyway as my MOAB gives a good flood. I have a question about reflectors though. What kind of reflector (if any) should I be looking at? Should I buy the reflector with the glass at the same time as a kit? I'm not sure what I want to use as my light head yet (maybe a Mag head as they seem to work well).

I was thinking of running a Nickle Metal Hydryde or Lithium battery between 12 and 14VDC and I was going to use a handlebar switch for easier control.

I haven't decided if I should use the 3 or 4 cree LEDs. Maybe I'll run 3 and a fourth on a switch. Is that ever done??

Thanks for any and all heckles, jeers, and advice.

Andrew.

 

[LukeA]

The buckpuck will only power a string of LEDs whose total forward voltage is less than the input voltage of the battery. So, the NiMH pack will be fine for 3 emitters, but the 14.4 will be necessary for 4 emitters.

 

[neex]

Thank you. I had anticipating perhaps that I was a little conservative on the battery output needs. I've also heard that the regulation circuit in the buck pack will rob a few volts from the battery. I suppose I need to put on my beancounter glasses and check out the specs first. Is there any reason that I can't sit these LEDs in high temp silicone for isolation rather than that arctic stuff everyone raves about?

Thanks,
Andrew.

 

[shakeylegs]

I have no experience using silicone as an emitter adhesive. The idea behind arctic epoxy is that is helps transmit heat from the emitters to the heatsink. I would be concerned that the silicone insulate the emitters and prevent heat transfer. On several counts overheating is a poor idea for emitters.

 

[neex]

I have no experience using silicone as an emitter adhesive. The idea behind arctic epoxy is that is helps transmit heat from the emitters to the heatsink. I would be concerned that the silicone insulate the emitters and prevent heat transfer. On several counts overheating is a poor idea for emitters.

Thanks. Evidently, like all other projects, there's a tool for every job and a job for every tool. Arctic Silver it is then. I still need to get my light head sorted first. I think that turning something might be best.

Thanks again,
Andrew.