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Author Topic: Dummy Load for LED lights / eliminate flickering  (Read 265715 times)

Offline SirMeili

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #165 on: November 13, 2014, 07:55:41 pm »
Yup.... Unless they changed how they are made, mine work fine. I might have one still in packaging to check the model number against but I have zero flickering with any of my Cree bulbs.

Edit.. I just checked and my model number ends in 1U100 not 2U100. Looks like they may have changed something.

« Last Edit: November 13, 2014, 08:14:28 pm by SirMeili »
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Offline brandoncreel

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #166 on: January 18, 2015, 02:00:01 pm »

However, that load is only present when the lights are on......so there is little or no heat at all when dimmed down or in the off position.
True, but also for safety you need to plan your heat budget under the scenario that the dimmer is on 100% 24/7, even if in practice it isn't.

Absolutely.....saftey always comes first. The final install will be using aluminum cased 1.5K thermal resistors (picture below).
They can be mounted in the lighting can or in our case we are remote mounting them to an aluminum plate that forms a great heat sink. These should not be used inside a wall switch or in a plastic enclosure....this is where common sense needs to be used.

I will post a finished photo tomorrow ..... end results are stable dimming rates and No Flicker for 10 different styles and brands of LED Lighting! The lights still cannot go below a 10% dim.....thats where they stop but the benefits are obvious. We have switched to an EcoSmart 9 watt (40 watt equivalent) LED bulb and they are working great for general overhead lighting in our yachts. These put out 3,000 K light temp and I wish I could get them closer to 2500....just a little more yellow would make them perfect.

Tim Alls
AllSeas Yachts

Thanks Tim!  I did exactly as you stated and my leds are dimming great. For others, I had 4 x 9.5 watt leds from Home Depot and my GE dimmer has a 40 watt incandescent (resistive) minimum load. From time to time I'd get flickering of my lights but by adding the resister they look perfect!!!

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Offline healeydave

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #167 on: January 23, 2015, 01:32:08 pm »
I wonder if anyone can help me.

I tried to use the information in this thread to sort my Dimmable LED issue out.

I am in the UK, so am operating on 240V.

I have a 8 GU10 light fittings in my lounge. These are configured in 4 Pairs and go back to a NJD DPX4/10 Dimmer pack (so 4 circuits):
Diagram of Lounge Configuration:

Dimmer Pack:

I have swapped out traditional 50W Halogen Bulbs for Dimmable 4.5W LED's, so a total of 9W is running on each output circuit of the Dimmer Pack:

I tried to order some 3K 25W Chassis Resistors from a local supplier but they sent the wrong ones, I ended up with 4K7 25W 5%

I decided to install these anyway as after reading through the thread, there seemed to be some ambiguity as to what would work in the UK on 240V anyway so call me the guinea pig :-)

I installed one of these resistors in parallel on the Dimmer Packs output line (to the GU10's) across the Neutral & Live on each circuit output.

The result was the LED's work fine with negligible flicker and also DIM through the levels I had already programmed for the previous Halogen bulbs which I was ecstatic over.

Trouble is, my satisfaction was short lived, after being on for something between 30 mins to 1 hour , I noticed a burning smell coming from the Dimmer Pack. I cut the power off whilst everything was still working fine.

I haven't had chance to take it apart and inspect yet (thats a job for tomorrow).

Anyone know what could be wrong because I think my implementation was ok from a working standpoint anyway :-(

Attached is a pic of the Resistors installed at the top of the dimmer pack. I chose not to mount them on the metal chassis due to space but could it be simply that they were getting too hot that was making the smell?


Ok, whilst waiting for a few days moderation, I had time to investigate.
I'd already decided the implementation was probably sound due to the fact that nothing had blown or stopped working and on further inspection, I discovered the plastic on the "chock-block" connectors I used to make the connections was melting from the heat of the resistors causing the smell.

I revisited the installation and mounted the resistors on the lid of the dimmer pack and soldered the connections this time.
I've been monitoring the heat and it seems perfectly acceptable. The case is doing a good job of aiding dissipation, it gets quite hot to touch literally where the resistors are mounted after the lights have been on full brightness for a few hours, but it does seem to plato out to a level that I wouldn't deem a danger.

Ok, It appears I have an over-heating problem with this solution when using the LEDs on full brightness levels.
My lights are cutting out after a period of time, presumably the dimmer pack has a thermal cut-out.
Upon observation after such an incident, the case is very hot and if allowed to cool down, starts to operate again there-after.

As there have been no replies to this thread since I started this project, I think I am going to have to concede defeat and look for an alternative solution as I have exhausted my knowledge of what has been previously written.

Also, to be honest anything that generates this kind of heat makes me think this was never going to be a particularly efficient solution.
« Last Edit: February 04, 2015, 04:25:30 am by healeydave »

Offline tyfoon

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #168 on: March 27, 2015, 04:34:46 pm »
Maybe this is a very stupid question but can't find the answer:

I have about 6 of these fibaro bypass resistors in place. If the light is out, do they actually consume power? if yes, how much?

Offline baldhead

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #169 on: March 28, 2015, 08:33:01 am »
the bypass is rated 1w at full load, and I only need it when there is no neutral in the switch's box


Offline aseriesoftubes

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #170 on: May 15, 2016, 08:52:27 pm »
Apologies for reviving an ancient thread.

I purchased an 25W 1.5kΩ 1% tolerance resistor (this one), and wired it in parallel with an LED downlight in one of my ceiling cans. It didn't do much to reduce buzzing, although it did seem to help with the flickering issues I've been experiencing. However, after a couple hours of operation, it got extremely hot; the heatsink on the resistor measured 300 degrees F (150 degrees C), according to the temperature probe on my multimeter.

Is anyone else experiencing these kinds of heat issues? I was extremely uncomfortable transforming a ceiling can into a miniature oven, so I took the resistor out.

Here's some info on my system:
  • Voltage: 110 (US)
  • Lights: Cree TW-series recessed LED downlights
  • Switch:Cooper RF9540
  • Resistor: Vishay RH0251K500FC02
« Last Edit: May 15, 2016, 09:36:01 pm by aseriesoftubes »

Offline Z-Waver

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #171 on: May 20, 2016, 10:15:23 am »
25 watts is too high. It's going to get very hot. As the post previous to yours states, they use a 1 watt resistor and only when the dimmer has no Neutral.

The Cooper RF9540 uses a Neutral and does not require resistors. It is also made specifically to handle LED bulbs and should have no problem with a Cree bulb.

What's buzzing, the switch or the bulb? That switch/bulb combination should work without flickering or buzzing without any resistors. If the bulb is buzzing, I would suggest that you try a different bulb. I have had a couple of defective Cree bulbs in the past.

Offline Hossam Sakr

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #172 on: April 03, 2017, 11:53:19 am »
i was really amazed buy founding a solution for my problem
but i need to get sure of some points before trying to use two 10W 3.3k resistor to each channel connected to LED spots
my dimmer is 400W/channel (philips Dynalite DDLE802)
shall i use the same two 10W 3.3k resistors or should be changed as its 400W not 1000W?
can i connect these resistors between one of the spots terminals or legs in the circuit?
what about the heat results from dimming on these resistors?

Offline JimmyV

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #173 on: February 07, 2018, 06:54:28 pm »
There's an interesting dummy load solution here:  https://www.youtube.com/watch?v=zwmA22wMgZw

It may or may not work for your situation.