problem in design of torch

[dckjain]

i want to design a torch in which i am supposed to use any number of 5mm LED but i should be able to throw a light for about 250-300 feet (75-90yards)

what should be the optimal number of LEDs and the lumen's required

and the rechargeable battery required for the peak use of around 2- 3 hours

please suggest any reflector and lens if u have any idea.

actually i am from india and dont have enough idea about long range torches

please help me

 

[eebowler]

5mm LEDs are not designed for throw. The have a beam pattern of 15-20 degrees typical which is determined by the manufacturer. A light that has lots of throw has a beam pattern of 6 degrees or less...

The only way (that I know of) to have lots of throw from a 5mm LED light is to have lots of LED. This way, the large volume of light (high lumens) produced will give you 'throw'.

 

[TorchBoy]

Are you committed to using 5mm LEDs?

 

[kts]

If you dont know anything about torches, it would probably be a lot easier to buy one instead..as said, you will not get a lot of throw from 5mm LEDs :candle:

 

[Fallingwater]

You could use 10mm LEDs instead. They still aren't the optimal solution (which would be a Cree and the appropriate reflector), but their beams are rather more concentrated than those of 5mm LEDs.