Weird Issue w/ LED Bulbs and a Remote Control Fan

I’m in the process of switching all of my lights to LEDs, so far everything has gone smoothly. That is, until I changed the lights in one particular fan.

When these LED bulbs are in the unit, the remote control (RF) can turn the lights on, but not off. While the lights are off, the fan is controllable, but when the lights are on, the fan is also uncontrollable.

Everything works fine with one LED bulb (and the other two sockets empty), but breaks again when two LED bulbs are present (it intermittently works).

Interestingly, I was able to find a workaround. If two sockets have LED bulbs and the third has an incandescent bulb, everything works normally.

My guess is that the bulbs are causing interference on the power line and messing up the receiver, but the filament in the third incandescent acts to filter it. I’ve ordered some LED bulbs from another manufacturer to see if it’s specific to these bulbs. If anyone has a suggestion or theory, I’d love to hear it.

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I think your analysis is reasonable. It would be hard to know for sure without taking an oscilloscope to it.

  1. LED lighting has caused a lot of trouble with 300 MHz radio communication

  2. In particular, pulse width modulation (PWM) used in LED lighting causes interference if not filtered.

  3. Incandescent lights lag, similar to an inductor, skewing the frequency response.

I’m guessing that your incandescent bulb simply shifts the problem to a different frequency, one that you aren’t using.

“Hey, Rocky, watch me pull an answer out of my hat!”

http://homeenergypros.lbl.gov/forum/topics/led-s-interfering-with-garage-door-openers
http://homeenergypros.lbl.gov/profiles/blogs/led-lighting-garage-door-opener-interference

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I wonder if load on the circuit has anything to do with the issue? I know that led bulbs have a lower load than incandescent bulbs. Just another wild guess.

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Yeah, I’d chalk it up to “barely adequate RFI design”. A friend and I were working to diagnose why his garage door opener wouldn’t work after he replaced the floodlights on the outside of the garage with LED models. We even moved the GDO to a different circuit with a heavy extension cord to eliminate the possibility of power-line interference.

At my previous job, we had a RFI setup with a log-periodic antenna and a spectrum analyzer in a shielded, anechoic chamber to track these down. You’d get some pretty nasty plots off of the cheaper cable modems.

Chances are that it’s a load issue. Is the light circuit set up as a dimming circuit (where it dims / brightens as you hold the light button)? If so, it may simply be that the circuitry isn’t recognizing that there is a light there and causing it to freak out. This would explain why it works with even one bulb.

I don’t think it’s a dimmer circuit, but I’ve never tried holding the button down before.

Andrew,

What is the make and model of the remote control fan?

Do you run X10 or any other home automation protocols?

JAG “2 out of 3 LED Bulbs Recommend It” MAN

It’s a Harbor Breeze fan, I don’t know the model though.

I have no X10, just wifi, a Nest Thermostat and Nest Protects.

Andrew,

I think you, Richard and Zach are on the right trail. I seem to have verified that the Harbor Breeze fan remotes run on the 303-304 MHz band:

http://www.remotecentral.com/cgi-bin/mboard/rc-x10/thread.cgi?2830

Let us know how the new bulbs work out. Perhaps a mixture of different LED bulbs will solve the problem; if not, I know a few other tricks that can be pulled out of a hat.

JAG “Smith Charts Are Sexy” MAN