Re: LED dimmable bulbs with X10 switches

[Geoff <geoff@xxxxxxxxxxxxxxx>]

On Sat, 21 Feb 2015 11:03:33 -0800, "Bob F" <bobnospam@xxxxxxxxx>
wrote:

>Bob F wrote:
>> I just bought some Cree LED soft white "60W" "4FLOW filamant design"
>> bulbs.
>> On one circuit, with just one bulb, the bulb lights at a mid level
>> when off or full brightness when switched on at the switch. The
>> switches involved are the old X10 switches with a lower section that
>> slides to the left to cut off all power. The problem is that the X10
>> controller cannot turn that bulb either on or off. Turning other
>> circuits using the same controller continues to work fine.
>> On another circuit, there is a 2 bulb fixture downstairs and a 2 bulb
>> fixture upstairs, all currently incandescent bulbs. If I remove one
>> of the incandescent bulbs downstairs and replace it with the LED
>> bulb, everything works OK, with the incandescent bulbs dimming much
>> more than the LED bulb when the dimming function is used. When I
>> removed the downstairs incandescent bulb,leaving the LED bulb, again
>> I could not control the lights with the X10 controller. This is
>> despite the 2 incandescent bulbs in the upstairs fixture.
>> Has anyone here seen similar problems, and come up with any solutions
>> to them?
>> I do realize that the low brightness issue in the off position of the
>> initial circuit is do to the switch sense feature of the X10
>> switches, and that the incandescent bulbs in the second circuit
>> eliminate that problem there.
>
>I just tried the second circuit again, and it seems I can turn in off with the
>controller, but not on.
>

You are dealing with a limitation in the triacs in the X10 that switch
the current to the load on and off. There is a minimum sustaining
current that a triac needs to keep itself on after it's been fired by
the trigger circuit. Replacing an incandescent with an LED can put you
below that minimum current and cause the triac in the X10 module to
turn itself off.

The load required by an X10 dimmer varies with the manufacturer but
what I've found during a quick google search is a 40W minimum might be
typical. At 120VAC this means the minimum load current needs to be
around 0.33 Amps.

With LED technology you need to ignore the "wattage" of the bulb since
it's an equivalent rating, not a power consumption rating. A Cree 60W
equivalent bulb uses only 9 to 9.5 Watts in the soft-white and
daylight types and that's less than 0.08 Amps at 120 volts, a very
economical current indeed and about 4 times less current than a 40W
incandescent will draw.

If it's a multi-bulb fixture you can add three more LED bulbs to get
the total current up into the sustaining range of the X10 but it may
be more economical to use an appliance module instead. It uses a relay
and you lose the dimming capability and the "all lights on" capability
but if remote on-off is your desire then it's definitely preferable to
loading up on LED's just to get back into the higher current draw that
LED's are supposed to be avoiding.

P.S. I love my Cree LED bulbs and I've made it my goal to replace all
my incandescents with Cree bulbs as the incandescents burn out.