Why are there different dimmer light levels

[Nigel Deacon]

I have two rooms.

One room has 12 LED ceiling lights with two switches. One is a regular switch the other is a dimmer.

The second room has 8 LED ceiling lights with a single dimmer.

The LED's in both room are the same, and the dimmer switch is the same. So the only difference is the regular switch in the first room.

So the question, why does the dimmer in room two make the lights a lot dimmer than is room one?

 

[telectrix]

might be the fact that there are 12 on 1 and 8 on the other.

 

[goasis]

There may be an electronic reason due to the number of fittings, I'm not sure, I do know that with quite a few models of led dimmers you can adjust the minimum dimming level

 

[Midwest]

Do you know what make they are?

 

[Wilko]

Hi Nigel and Welcome to the Forum .
Dimmers and leds are just fun fun fun, as you've found. My first thought is the dimmer units are set differently in the 2 rooms. Led dimmers often have a micro processor inside which may be set for minimum brightness. What make / model are your dimmers?

 

[Lucien Nunes]

Although the LEDs and dimmers are the same in both rooms, perhaps the drivers are different, with a different response to the same dimmer output. If the dimmers are configurable, is one set to leading edge and one to trailing edge?

 

[Shoei]

Historically, dimmers used phase-angle switching to vary the power in the load - usually a filament lamp. A triac switch does the control and if (say) it gets switched on 5ms after the zero crossing point, then the load is on for 50% of the time, 2.5ms 75% of the time etc. Half power isn't usually half brightness, there's a non-linear relationship.

Dimmable LEDs can't use this directly, they have inverters to convert the mains into a low-voltage, constant-current drive. Dimmable LED's try to guess how bright the LED should be by measuring the phase-angle switch point but there's no standard for how that works. One manufacturers guess may be much different than anothers.

In principle it shouldn't make any difference to have more LEDs on a dimmer but variations between dimmers that wouldn't be visible on a filament lamp may have a big effect on an LED. The dimmer may have compensation to accommodate different loads and that could have an unwanted effect on the LEDs. The LEDs themselves can show big variations.

All you can do is experiment with different combinations until you get the result you want. For multiple LEDs it's worth holding a spare or two so you have an identical part if one gives up later.

There's some guff about dimmers here if you ever have trouble sleeping

 

[plugsandsparks]

some dimmers have presets for minimum level, perhaps thy are different

 

[Midwest]

Anybody else wanna say the dimmers might not be adjusted to their minimum

 

[Squid]

Takes Shoel off Christmas party invite..........