A high powered LED lamp

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CrewCab:
Now I do like that :thumbup: .................. what's the overall diameter of the aluminium Tim, I'm guessing about 25mm?

Ralph, earthing through the ally casing should work :scratch: ................... guys are my calcs right in that the 2Amp power supply is just about right for 3 x LED's :smart:

CC

spuddevans:

--- Quote from: Divided he ad on August 19, 2009, 05:02:20 PM ---P.S. Just a thought.... Could you ground all the LED's to the casings, using the clamp to connect the earth wire to and only have one wire going to each housing for the positive feed? (Bit like how I do my torches)

--- End quote ---

Yes you can do that, I should have done that but I got a little confused as to which power supply I had. Dx do several different ones, some have the LED's in serial (which I thought this one was, until I had finished it all and wired it in series, only to find no light when switched on ) and ones that power the LED's in parallel. So I had them all wired in serial, tested it and then had to re-wire. I was just wanting to get it running, so I just bodged quickly re-wired it to parallel.

--- Quote from: CrewCab on August 19, 2009, 05:26:58 PM ---Now I do like that :thumbup: .................. what's the overall diameter of the aluminium Tim, I'm guessing about 25mm?

--- End quote ---

The ali is 22mm round :thumbup:

--- Quote ---guys are my calcs right in that the 2Amp power supply is just about right for 3 x LED's :smart:

--- End quote ---

Yep, dead on for 3 x 3watt LED's, or 1 9watt ( really really bright )

These are really easy to make, and would work great as additional lighting for a mill or lathe.

Tim

Brass_Machine:
Quite nice... we all need things like that in our shops!

Eric

Darren:
Very nice indeed,

Just bear in mind that the higher the voltage you put through an LED the brighter it burns......and shorter it lasts......and I belive it's exponential

spuddevans:

--- Quote from: Darren on August 20, 2009, 11:34:15 AM ---Very nice indeed,

Just bear in mind that the higher the voltage you put through an LED the brighter it burns......and shorter it lasts......and I belive it's exponential

--- End quote ---

That's very true Darren, these particular LED's that I used have a max voltage rating of 3.8V (as I remember), you can overcook them slightly, but it will run a lot hotter and have a shorter life. Also when you use even a slightly higher voltage, say 4.5V, which is only 0.7V more than the rated max, the current consumption goes up quite a lot, I think it can go up from 0.6Amps to well over 1amp,. hence the extra heat generated. In reality it is the Current that you have to worry about with LED's. The ratings of current are the ones to pay close attention to :zap:

If you are thinking of making a LED based lamp like I did, the best thing to do is to use a power supply designed for LED's. Dx do several including the one I used, and they are constant current types. This means that the power supply will automatically adjust the output voltage to keep the rated current constant. ( this is within reason, most of the constant current supplies will give the range of voltages the supply can deliver )

So you decide how many LED's you want to use, then find a power supply that can give you the needed voltage and current. This will depend on whether you intend to put the LED's in series or in parellel. Some LED power supplies put out a constant current of 330mA at a voltage range of,say 24-32volts, a power supply with that rating would be able to power between 7 and 9 LED's wired in series, and would automatically adjust itself to the right voltage to give the rated 330mA.

Or the power supply I used was a 2Amp constant current at 3.5-3.8Volts, this can only power LED's in series, so I was able to get 3 x 3W LED's in parallel.

Tim

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