I want to build a dirt bike LED headlight, advice please.

[michaelmcgo]

I Plan on building a headlight assembly with brightness equivalent to a 50W automotive bulb. The bike has a 12v 4A battery. I was thinking of a cluster of Luxeon, Seoul, or Crees, how many can I run off a battery of this size. I work in a CNC shop and can design/cut just about any style of aluminum housing. I would like to pack the LEDs as close as possible, and can make my own reflector out of the aluminum housing. I will need some advice as far as what kind of electronics I should put into it, such as resistors to get the input electricity where I want it. Thank you.

 

[LukeA]

Wire seven of these in parallel off of the battery. That's all. They can take what the battery supplies.

 

[Gunner12]

For that amount of output, I think 7 Cree XR-E LEDs(I'd recommend the Q5 bin) or Seoul P4 U-bin LEDs should be enough.

Drivers, I think three of these should work.

Wiring up the above drop-ins would be a simpler option(not sure about size though).

 

[nein166]

Heres a bicycle mod to see whats been done with these drop-ins
Just add a good lens to keep the mud out
Theres an index in the Transportation Lighting sub-forum

If you can get the drivers Gunner12 recommends (they've been sold out for weeks)
Make a custom light bar or 2 like this http://bikeled.org/

 

[michaelmcgo]

It's been years since I've had an electronics class, and don't remember a thing! Can I wire lets say 3 of these (or any 3.7v LED) in series on a 12v input? Should I wire up 4 instead and undervolt them a bit? Why should I use a driver, or is direct drive okay? what do I get by using a driver (the battery is being continuously charged)?

 

[Gunner12]

Three will overdrive the LED(not including voltage spikes and stuff, which could destroy the LED) and 4 won't have enough output.

A driver would ensure a constant current and constant output.

 

[LukeA]

Three will overdrive the LED(not including voltage spikes and stuff, which could destroy the LED) and 4 won't have enough output.

A driver would ensure a constant current and constant output.

Perhaps like THESE?