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Dimmable LED’s

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Dimmable LED’s

Postby Woodster » 20 Aug 2019, 15:57

Anyone know anything about them? I’m getting conflicting advice at the moment. The lamp I have is a single 12W COB LED.
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Re: Dimmable LED’s

Postby Robert » 20 Aug 2019, 16:23

My experience is that dimming them is temperamental.

You usually need a leading edge dimmer not a normal tungsten lamp one....but sometimes a normal one will work...sometimes.

because the dimming involves cropping the waveform....in some way that doesn't make sense to me... you need a wattage rating based on the 'equivalent watts'. So 50W rating dimmer to dim a 5W LED lamp and so on.

There can be a minimum load as well as a maximum so 1 lamp on its own may not dim properly.

For our install of 17 x 7W LEDs on one circuit and 8 on a second circuit I ended up with a high power twin leading edge dimmer from toolstation (which they no longer sell). That was after trying a couple of 'led dimmers' and finding they didn't work because they were under rated at 250W for 17 x 7W lamps. the derating thing was hidden in the small print in the instructions and nowhere on the site I ended up returning it to.

That was all 5 plus years ago so maybe things have got better by now. Good luck!
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Re: Dimmable LED’s

Postby Woodster » 20 Aug 2019, 17:59

I’ve been advised by some to just get a standard LED suitable dimmer whilst others have suggested something that adjusts the voltage like a motor controller.
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Re: Dimmable LED’s

Postby DaveL » 20 Aug 2019, 18:07

The lamp you are trying to control needs to be a dimmable type, all of the lamps have a circuit to reduce the mains down to the correct voltage for the LEDs, some of them will not work on a dimmer as the electronics will try to run the lamp at full brightness or not at all.
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Re: Dimmable LED’s

Postby Robert » 20 Aug 2019, 18:13

yes i missed that bit out...all lamps need to be dimmable type.
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Re: Dimmable LED’s

Postby Woodster » 20 Aug 2019, 21:09

The current one I have isn’t dimmable as I didn’t expect to want to dim it but the replacement I’ve ordered is.
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Re: Dimmable LED’s

Postby HappyHacker » 21 Aug 2019, 18:31

A few years ago it was an absolute pain dimming LEDs, even the supposedly dimmable ones. Some would only work with certain dimmers, most would not work with dimmers not designed for LEDs some would flicker when dimmed even with the recommended dimmers.

Now it is slightly less of a pain as most dimmable LEDs will work with most LED dimmers most of the time.

Ideally you would get a dimmer that has an adjustment to set the minimum dimming level which does not cause flicker and that remembers it if there is a power cut. There is lots of choice now from cheap and cheerful to relatively expensive. Having had my fingers burnt on more than one occasion I do not make any recommendations.
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