5mm LEDs for Strip/Tube Lighting

[Vardarac]

Thanks for the compliment. However, I got into the idea building my own saber without being biased for any particular technology. I don't see why you assume that I am a "Lux man" merely because I have a presence on the TCSS forums.

Anyway, back on topic- this is more for Skywise's reference- I didn't have much luck trying to diffuse my LEDs by shaking them in sand.

 

[Oznog]

Even a "quality" mfg does not guarantee Vf will be matched so the initial current will be balanced when paralleling. It's "nice" and high quality mfg often does have closely matched Vf but it's not a really significant criteria.

It won't matter much anyways, because of the negative temp coefficient of Vf. In parallel, even if perfectly matched, the one on the middle will be warmer than the one on the end, dropping its Vf which increases the current on the hot one and decreasing the current on the cold one. This further increases the current and temp of the hot one and can result in a destructive thermal runaway, or at least just a visible inconsistency in light intensity or lowered life because some devices are being run at more than the max rated current.

 

[Vardarac]

Even a "quality" mfg does not guarantee Vf will be matched so the initial current will be balanced when paralleling. It's "nice" and high quality mfg often does have closely matched Vf but it's not a really significant criteria.

It won't matter much anyways, because of the negative temp coefficient of Vf. In parallel, even if perfectly matched, the one on the middle will be warmer than the one on the end, dropping its Vf which increases the current on the hot one and decreasing the current on the cold one. This further increases the current and temp of the hot one and can result in a destructive thermal runaway, or at least just a visible inconsistency in light intensity or lowered life because some devices are being run at more than the max rated current.

Adding additional wires from the power source to dimmer sections of my LED string seemed to alleviate the problem (the string was brightest closest to the power source, so I added two more lines, one in the middle and one at the far end).