SMJLED BiPin at 3.6v, 165ma. RT Graph. Amazingly bright

I have an old MXDL "Luxeon" torch.

The 1w "Luxeon" led has burnt out / stopped working.

I've just replaced this with a SMJLED BiPin led, seems to work very well, very bright.

At 3.6v, initial current= 165ma

Doesn't appear to run hot. At 30 mins in, it is slightly warm to touch only.

Output, measured, focussed beam, equivalent to L2P, brighter than L1P.

I'm obviously overdriving the SMJLED a bit, anyone else done this, expected SMJLED life ?

RT on nimh 900mah should be pretty good.

Re: SMJLED BiPin at 3.6v, 165ma

For reference, the following thread by Chimo has very useful reference for all various 5mm comparison and the MJ went downhill pretty fast after 24 hours of overdriving at 105ma.

https://www.candlepowerforums.com/threads/89759&page=1&pp=20

If the SMJ's spec resemebled the MJ's, then the setup is definitley overdriving the led by close to quadripple its' original spec. I was told that the original MJ could be overdriven close to around 90ma, but anything close to or beyond 100ma will cause some long term effect. If I could suggest anything, my humble suggestion will be to place in a resistor before the 5mm to reduce the current driven to the led.

Re: SMJLED BiPin at 3.6v, 165ma

I ran the 3.6v SMJLED for 2 hours at virtually constant high output, similar to L2P output.

Then, output dropped over next hour, to effectively min useful level..

So, RT 2 hours full, then another hour dropping.

This is in a MXDL 3xAAA 3.6v 900mah nimh, no regulation torch.

Re: SMJLED BiPin at 3.6v, 165ma RT Graphs

RT Graphs for SMJLED run at 3.6v (3xAAA nimh 900mah)

All other torches using 2,000 mah AA Sony nimh batteries.

Comparison really to show brightness and RT of SMJLED run at 3.6v, direct drive, replacing a dead 1w "Luxeon" in a MXDL torch with focussed beam.

Previously, the 3!!w "Luxeon" gave similar output for similar RT of 2.8 hours.

So, if the SMJLED was to replace a Luxeon in a 3AA 2,000 mah torch, RT's would naturally be greater.

Possibly double.






X axis divisions are 30 mins each.

Min useful illumination = 8.0

Direct comparison of illumination output as measured with Lenin 4 light meter

Re: SMJLED BiPin at 3.6v, 165ma

AuroraLite said:

MJ went downhill pretty fast after 24 hours of overdriving at 105ma.

Click to expand...

The SMJLED is obviously overdriven, but I think by not much.

It gets very slightly warm to the touch, so I do not think thermal runaway will be a problem.

As a way of resuscitating an old "Luxeon" torch, it works a treat.

It won't be used in continuous mode either, even 24 hours will be a long time in the life of this mod.