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[Walt2]

I bought a couple of the dimmable CFL bulbs, and placed them into table lamps that are controlled by a LM465. 

The problem I am having is that they don't dim a whole lot.  I would say I can dim them down to about 80%.  Anything less, and they simply shut off.  Matter of fact, I thought something was wrong with them at first, and that they weren't dimming at all.  That was until I put a dimmed lamp next to another lamp that was still at full brightness.  By doing that, I could finally notice a slight decrease in the ight level from the dimmed lamp.

Is that normal?    Is that what the rest of you all are finding with these dimmable CFL bulbs?

The LM465's are the only way I have to dim my table lamps.  So, is being able to dim only to about 80% about it for these CFL bulbs, even when one attempts to dim them with a non-X10 type of dimmer?

I found this quite a disappointment.  When I 'dim', I usually want a pretty low light level like that of a night light.  If the dimmable CFL bulbs are only slightly dimmable, I will need to start hording incandescent bulbs. 

[dave w]

I bought a couple of the dimmable CFL bulbs, and placed them into table lamps that are controlled by a LM465. 

The problem I am having is that they don't dim a whole lot.  I would say I can dim them down to about 80%.  Anything less, and they simply shut off.  Matter of fact, I thought something was wrong with them at first, and that they weren't dimming at all.  That was until I put a dimmed lamp next to another lamp that was still at full brightness.  By doing that, I could finally notice a slight decrease in the ight level from the dimmed lamp.

Is that normal?   

The LM465's are the only way I have to dim my table lamps.  So, is being able to dim only to about 80% about it for these CFL bulbs, even when one attempts to dim them with a non-X10 type of dimmer?

I found this quite a disappointment.  When I 'dim', I usually want a pretty low light level like that of a night light.  If the dimmable CFL bulbs are only slightly dimmable, I will need to start hording incandescent bulbs. 

I think (estimate) mine dim more than 80% of full bright, but I am sure they do not go as low as 50%. The CFL works by ionizing gas and when the voltage drops below the ionization point, the lamp just "winks" out. That is just the nature of dimming a fluorescent light. You might try a different brand of dimmable CFL, but it sounds like you are getting fairly normal operation.

[Walt2]

I think (estimate) mine dim more than 80% of full bright, but I am sure they do not go as low as 50%. The CFL works by ionizing gas and when the voltage drops below the ionization point, the lamp just "winks" out. That is just the nature of dimming a fluorescent light. You might try a different brand of dimmable CFL, but it sounds like you are getting fairly normal operation.

I was hoping that it was just the brand (I think GE?) that I bought, and that someone here could recommend a different brand might have implemented it a bit differently with better results.

I haven't given this much thought, but possibly a "dimmable" CFL which implements something like the old 3-way fluorescent light adapter I bought a decade ago?   I mean, having two or three separate tubes, and using the voltage level as a reference to turn 'on' or 'off' the various tubes.  One could have a 5watt tube, a 15watt tube, and a 20 watt tube, that could produce light levels of 5w, 15w, 20w, 25w, 35w, and 40w.

[Brian H]

I have ULA SDS-23W bulbs and they dim down to maybe 20%. Note below maybe 50% they do tend to flicker.
One thing you may want to try is what I read on one of the manufacturers web sites. Before dimming a new bulb. Burn it in for an hour or more at full brightness.
I did mine; though I never tried a fresh from the box one.

Also said best to start at 100% and dim down. I know an Insteon Lamp Module if you don't set the ramp rate to fastest causes unhappy Dimmables. Guess the Soft Start LM465s may also be a problem.
 
Some have reported that the local sensing circuit in the modules make some brands CFLs flicker when off.

[Dan Lawrence]

The cheapest way to stop CFL's from flickering is to plug a cube tap into the module (lamp or appliance) and plug a nite light and the lamp cord into it.  The nite light draws just enough current when off to kill the flicker.

[Brian H]

Good point Dan.

Found another dimmable. An OLD style; 4 U Shaped Tubes; GE: FLE29QBX/DV/827 29 Watt
Once warmed up it would dim down to maybe 30%. Didn't seem to flicker much but didn't dim nice; if not warmed up for maybe a minute or two.

[Walt2]

I have ULA SDS-23W bulbs and they dim down to maybe 20%. Note below maybe 50% they do tend to flicker.
One thing you may want to try is what I read on one of the manufacturers web sites. Before dimming a new bulb. Burn it in for an hour or more at full brightness.
I did mine; though I never tried a fresh from the box one.

The ULA might be a good lead, thanks!

On youtube, I found this on Dimmable fluorescent test.  Watching that, the ULA CFL appears to dim a lot further down than the dimmable GE FLE26HT3/2/DV/CD CFL bulbs I bought at Walmart.

[Walt2]

Found another dimmable. An OLD style; 4 U Shaped Tubes; GE: FLE29QBX/DV/827 29 Watt
Once warmed up it would dim down to maybe 30%. Didn't seem to flicker much but didn't dim nice; if not warmed up for maybe a minute or two.

Hum, that is the CFL bulb I have.  Maybe I do need to be more patient and allow them to warm up first. 

However, having to allow them to warm up at a blinding 100% first, is like having to go back to using the old LM465 with an incandescent bulb which always power 'on' at 100%.  Kind-of kills any kind of slow "sun rise" mode in the early morning hours (who want to wake up to a blinding 100% light level?     ).

EDIT:  No, it is not the same bulb.  Sorry.   

[Boiler]

Hum, that is the CFL bulb I have.  Maybe I do need to be more patient and allow them to warm up first. 

However, having to allow them to warm up at a blinding 100% first, is like having to go back to using the old LM465 with an incandescent bulb which always power 'on' at 100%.  Kind-of kills any kind of slow "sun rise" mode in the early morning hours (who want to wake up to a blinding 100% light level?     ).

EDIT:  No, it is not the same bulb.  Sorry.   

Walt2,

My entire experience with "Dimmable CFL's" revolves around 1 Sylvania 15W reflector flood.  If I give this bulb 100% on for ~ 1 minute I can get it to dim reliably to ~ 20%. If you do not warm the bulb you will find them extremely non-linear and non-repeatable.

As Dave W indicated, the CFL's work on the ionized gas principle.  As the temperature of the bulb increases so does the pressure within the bulb (which increases the ionization process).

Bottom line - I only have 1 dimmable and I'm not planning on any more in the near future.

I have read that the "code cathode" CFL's are for more linear and dimmer friendly.  When they start producing a unit that gives off a reasonable amount of light at a reasonable cost, I may give them a try.

Boiler

[dave w]

I have read that the "code cathode" CFL's are for more linear and dimmer friendly.  When they start producing a unit that gives off a reasonable amount of light at a reasonable cost, I may give them a try.

Boiler, I think I just learned something. I thought all CFLs were Cold Cathode...not true?

[Boiler]

I have read that the "code cathode" CFL's are for more linear and dimmer friendly.  When they start producing a unit that gives off a reasonable amount of light at a reasonable cost, I may give them a try.

Boiler, I think I just learned something. I thought all CFLs were Cold Cathode...not true?

Dave, That was my understanding as well, until I encountered the "Cold Cathode CCFL's".

See the section "Other CFL Technologies" roughly half way through the following:

http://en.wikipedia.org/wiki/Compact_fluorescent_lamp

This document also indicates that standard CFL's are unsuitable for motion detector circuits.  It seems they do not like rapid on/off cycles (shortens the life span).  May have to do with the bulb not reaching full temperature thereby affecting the phosphor coating?

The CCFL devices do not share this problem and are considered "instant ON".  Unfortunately, most of the CCFL devices currently on the market are low equivalent wattage and expensive.  Not sure which will win out - LED's or CCFL's.

Boiler

[dave w]

And now I know...THANKS!!