Dimming Led Lights

[dave2]

Earlier this year I replaced all the tungsten lights in my local with LED's.

96 in total. 

Customer over the moon as he is over £100 a month better off.

They are spread over 5 circuits,  some of which have 20+ LED's.

He decided he wants to dim them so I ordered some 400W dimmer switches thinking that they will be ok. 

I installed the dimmers and now there are problems when they are switched on. They go on and off for a few seconds and then stay on. I must admit I was a bit snookered trying to fathom it out until I decided to read the small print for the dimmers and it states that a maximum of 10 only LED lights per dimmer. Apparently the start up currents for LED's is 6 x the power rating of the lamp for a few nanoseconds and this causes overloading of the dimmer.

Anyone else aware of this and any ideas of how to overcome the problem without rewiring?

Thought I would look for a 800W trailing edge dimmer but unable to source one.

 

[Andy™]

are the LED's designed to work with a dimmer? many are not

 

[dave2]

are the LED's designed to work with a dimmer? many are not

Yes all products compatible and purchased from one of our sponsors.

 

[Evans Electric]

Best thing with LED dimmers , until we're all more conversant with them , is to note the lamp type and load per cercuit  and speak to someone like Varilight  for advice .

 

[Steve3948]

Some dimmer modules state max LED wattage as stated on dimmer.

Danlers Resload for up to 8 LED fittings, so 16 would require 2+, worth a try.

I don't think its anything to do with start current but more low load.

We found 1 or 2 fittings dimmed fine but 6+ had flicker issues, fitted resload worked fine.

 

[dave2]

Best thing with LED dimmers , until we're all more conversant with them , is to note the lamp type and load per cercuit  and speak to someone like Varilight  for advice .

The dimmers are Varilight Pro V. 

If I spoke to to Varilight and told them I had installed 20+ LED's on one dimmer they may well tell me to read the installation instructions. i.e Max 10 per dimmer.

I don't think its anything to do with start current but more low load.

Some of the dimmers are not affected---those with < 12 LED's

 

[Steve3948]

They may tell you that, but at least you will know.

Philips Lighting explained to me the more low load electronics you add the more difficult it is for the dimmer to sense.

 

[dave2]

To clarify the problem:

1 MCB connects  2 dimmer switches.

Switch dimmer 1 on and everything works fine.

Switch dimmer 2 on and dimmer 1 lights flicker on and off and then everything works ok. 

This happens even when the dimmers are set to not dim ( if you see what I mean)

The repeat happens when dimmer 2 is switched first.

 

[Steve3948]

GU10 or Mr16, what make are the lamps, if Mr16 are you using the original halogen transformers, we found only high quality expensive retrofit Mr16 LED worked, the cheaper lamps needed transformers out and drivers in.

 

[electrics_new]

funny things LED's

I did a swap at the swap the other.

Customer had British Gas Electricity cover - faulty transformer and they wouldn't change it due to customer having put in loft insulation.  Enginner said it was a possible fire risk and so he couldn't change it.

Cut away some of the insulation and put in LED's into the existing transformers - worked a treat. Dimmer works perfect as well.

 

[dave2]

GU10 or Mr16, what make are the lamps, if Mr16 are you using the original halogen transformers, we found only high quality expensive retrofit Mr16 LED worked, the cheaper lamps needed transformers out and drivers in.

The laps are Lumilife GU10 fitting and dimmers are Varilght Pro. 

I removed the original dimmer switches and all the existing transformers.

 

[Steve3948]

Hmmm I have no experience with these lamps and normally fit Kosnic when no dimming is required and Philips/Osram  when dimming is required.

The Kosnic is about the same price but the Philips and Osram are double that.

 

[MeFil]

The limit on the number of LED's on a dimmer module is due to the repetitive peak inrush current. The inrush current can be very high (as you have found out) and can cause the dimmer to fail very quickly.

One solution is to limit the number of led's per dimmer but then you can get problems with not enough load on the dimmer and only getting 20% dimming, which still isn't any good. A resload can solve that, but that kind of defeats the object of going led (imho)

also worth bearing in mind is the max load of the yoke. That limits the number of dimmers you can put on the yoke (assuming you are using a grid switch)

My opinion.... domestic led downlights probably aren't best suited to a commercial environment. You're'e better of looking at other dimming technologies, such as 0-10v.

 

[Steve3948]

A Resload is only equal to one fitting though so not a big deal in the scheme of things.

Also the inrush is not a problem on decent quality fittings a TLED-444 8W can be treated as that 8W so on a 250W dimmer you could put 25 with no issues in theory according to the manufacturers.

Cheap lamps and fittings are a different ball game and the quality of the driver is where most issues arise.

 

[dsnd_medic]

Sadly as some of the previous comments have stated, you cannot dim LEDs with a dimmer switch. In my experience you need to use pulse width modulation in order to dim them. Unfortunately I don't think this is something readily available off the shelf but I could be wrong.

 

[Steve3948]

Medic - You can dim them provided you use the right lamp/fitting and compatible dimmer for the type of lamp/fitting you are installing.

We have hundreds with no issues providing you fit compatible units with each other.

 

[dsnd_medic]

Thanks Steve that's always good to know.

 

[SLIPSHOD & SLAPDASH]

Sadly as some of the previous comments have stated, you cannot dim LEDs with a dimmer switch. In my experience you need to use pulse width modulation in order to dim them. Unfortunately I don't think this is something readily available off the shelf but I could be wrong.

As Steve has said, you can dim dimmable LED lamps, i have done this to hundreds. I have also experimented with non dimmable  which do to a certain level, but dont recomend it.

 

[gembrain]

This new LED dimmer might be of interest - claims to dim up to 250W LED load

www.zanocontrols.co.uk

Not cheap but might save some rewiring...

 

[Steve3948]

I believe there are now few who supply LED designed dimmers , I know Danlers do, also a lot are stating Min/Max LED load.

We have used the Zano but it was leading edge and we needed trailing edge, so we used Aurora, 2nd option would have been the Varilite Pro.