Dimmer modification for LED lights

[lsmall]

Hi. I'm trying to find a way to reproduce this inadvertent hack in a more elegant way.

I am switching many of my light bulbs to LEDs. My house has a lot of MR16 halogen bulbs (e26 base, 110-115V) that blow out every few months and I want to replace them wit hLEDs. Many of these are on electronic dimmers which are not compatible with the LED bulbs. There are usually 6 of these 50w halogen lights on a circuit. I have found that if all the lights are changed to LEDs (6w) they experience flickering, which is expected for LED bulbs on an incompatible dimmer. However, if just one of six lights is left as the original 50w halogen, everything works fine with the remaining 5 LED bulbs.

While I'm happy with this inadvertent solution, I wonder if there might be a simple way to get things working with all 6 LED bulbs without replacing the dimmers. Could a resistive load be added to the circuit that would replace the effect of the halogen bulb? This is beyond my knowledge, but perhaps someone can suggest something.

Thanks

 

[MikeMl]

Since it takes at least one 50W Halogen to stabilize the dimmer, you might need a 50W wire-wound 300Ω resistor to provide an equivalent load. (Where to mount the 50W resistor to get rid of that much heat?) Maybe split it into six resistors, one each across the pins of each LED lamps

Kinda negates some of the power saving, doesn't it?

 

[MrAl]

Hi,

My question would be when you use the make shift solution does that mean you can then also dim the LED bulbs too, or do you have to leave the dimmer on high all the time? If you cant dim them then replace the dimmer switch with a regular switch.
If you can dim them then try using a smaller halogen bulb instead of 50 watts, like maybe 25 watts, and see if that works too. If it does, there may be an even lower power that works too, and so seek the lowest power that works and then add a and equivalent resistor somewhere or a regular house bulb.

 

[lsmall]

Thanks for those helpful replies.

I think I'm talking more theoretically at the moment as I'm just curious and I have a decent albeit inelegant workaround. Yes it probably would negate some of the savings, but aesthetically, all the bulbs would be the same rather than having one yellowish halogen bulb and 5 crisp white LEDs.

Yes the dimmer function actually does work when one halogen is left in the circuit and I agree, I might be able to get away with a lower wattage load to stabilize the circuit. My main worry about doing something like this, is the heat from the added load and where I would place it as was mentioned in the first reply.

Anyway thanks. If I end up trying out another solution, I'll post the results.

 

[MrAl]

Hi again,

Oh yes i know what you mean by the yellow junk light that comes out of an ordinary buib. I always hated that in lights of all kinds. When white LED's came out i was quite happy.

And yes you never know, it may only require 5 watts of resistive load to get it working due to the way the dimmer works. If you ask me it deserves a few minutes experimentation using an old bulb socket with a resistor soldered into it, or just an old socket with extension cord soldered to it and that regular lamp plugged in where you could try small bulbs like 20 watts, or even a night light bulb like 6 watts or something. If it works there has to be a way to get it mounted safely as those halogen bulbs get REALLY hot and they work out ok.

 

[lsmall]

OK, you convinced me. I'll rig up a testing apparatus. My wife will be thrilled

 

[MrAl]

Hi again,

Ok, just be careful ok? Also, maybe you could report back here when you find out some new info. Would be interesting to hear how this turned out. Of course a few pic's would really be nice

 

[Diver300]

The problem may be caused by the dimmer having only 2 wires, so that it has to get its supply current through the lamps. Halogen lamps will let a small current though with minimal voltage drop, so the dimmer can store some energy like that each half-cycle to run its circuitry.

With LED lamps, there will be a big voltage drop when even a small current is taken, and the LEDs will light under those conditions, so the dimmer might not be powered correctly, and the LEDs will be lighting when they shouldn't.

It might be possible to separate out the supply to the dimmer from the load connection, making it a 3 wire device. You could then power it (via a fuse and a safety resistor) independently of the LEDs.

However, the devil is in the detail and that might not work at all well, it depends on the circuit. Also it is mains, so testing and diagnosing can be dangerous.