LED Rope Lights+Dimmers? XMAS time fun

[rgbphil]

Hi,

Now Christmas time is coming, stores have been stocking LED Rope lights.

A red/green/blue/white/yellow set of ropes plus dimmers will make a nice simple colour changing setup.

The question is will these simple ropes have problems in the long term with dimmers.

I've seen people having trouble with LED lamps with inbuilt regulators and dimmers, these appear to have no transformers or controllers on them, they just appear to have resistors limiting current to the LEDs.

I quickly tested two ropes with an X10 dimmer, and the dimmer could indeed dim the lights, though it had trouble dimming all the way to zero brightness. Presumably the dimmer used the classic triac pulse width method of dimming and doesn't actually drop the width to zero, wherein the LEDs shine with whatever small pulse width is still left.

Anyway, anything else I should know about, nasty spikes etc....or is this only a problem with more intelligent regulation circuitry than resistors? Anyone have actual measured values of dimmer spikes or a link of such an analysis?

Phil

 

[Canuke]

some info in these threads:

http://www.candlepowerforums.com/vb/showthread.php?t=141810

http://www.candlepowerforums.com/vb/showthread.php?t=176083

 

[dave w]

Hi,

Now Christmas time is coming, stores have been stocking LED Rope lights.

A red/green/blue/white/yellow set of ropes plus dimmers will make a nice simple colour changing setup.

The question is will these simple ropes have problems in the long term with dimmers.

I've seen people having trouble with LED lamps with inbuilt regulators and dimmers, these appear to have no transformers or controllers on them, they just appear to have resistors limiting current to the LEDs.

I quickly tested two ropes with an X10 dimmer, and the dimmer could indeed dim the lights, though it had trouble dimming all the way to zero brightness. Presumably the dimmer used the classic triac pulse width method of dimming and doesn't actually drop the width to zero, wherein the LEDs shine with whatever small pulse width is still left.

Anyway, anything else I should know about, nasty spikes etc....or is this only a problem with more intelligent regulation circuitry than resistors? Anyone have actual measured values of dimmer spikes or a link of such an analysis?

Phil

The X10 Lamp Module has a feature called "Local Control" which senses if you are trying to turn on the lamp at the light socket, and will supply power to the lamp. The Lamp Module passes a small amount of current through the light all the time to sense when you use the socket switch. Not nearly enough to light an incandescent light but IS enough to light a LED light or LED rope, or make CFL bulbs flicker.

The simplest fix is to plug a 7 watt night light in the lamp module with the LED rope. The night light shunts enough of the sense current that the LEDs will extinguish. I have read that X10 new Lamp Modules (shipping in US for about 6 months now) will not keep the LEDs lit on the OFF state.