24V Loxone LED spot alternatives

[Dries Bex]

Hey guys,

Any of you did your lighting with 24V LED? (DMX or Tree)

And have alternatives for the Loxone ceiling spots/downlights?

Already found some on Voltus but looking for other alternatives.

Gr.

Dries

[Andrew B]

I have downlights from Lauren Illumination which I'm driving from a pair of 32 channel dmx controllers. These are 24v DC and CRI >90. Love them and they dim beautifully via pwm.

[Andrew B]

Oh, and I also have a handful of MR16 and a bunch of corn bulbs driven from the same system, albeit at a lower voltage (about 15v turned out to be best).

[Duncan]

Andrew,

which mr16 bulbs have you used? and do they dim as well as you would expect? ive had little success with the ones ive tried

[Andrew B]

They dim pretty well.  I’ve tried a few varieties from various sources (they’re cheap, so I tried 5-6 kinds).  The ones from 12vMonster.com are what I have installed now.  They dim pretty well.

Dimming constant low voltage DC bulbs is “interesting” (although less “interesting” than dimming mains AC voltage LED bulbs, and less likely to die from heat death of the driver circuits).  There are quite a few factors:

1) voltage

2) pulse frequency

3) minimum pulse width (%age) to light the bulb

4) pulse width at which the bulb is at maximum brightness

5) high frequency buzzing from the bulb (varies based on dimming %age)

6) high frequency buzzing from the driver (varies based on dimming %age)

7) current draw (varies based on dimming %age)

8) flickering or unsteadiness of light (varies based on dimming %age)

The Lauren Illumination downlights behave beautifully.  They come on at around 8% and smoothly ramp to 100%.  I’m using ~450Hz PWM.  Their power draw is also roughly linear with dimming.  Their CRI is very high.  Their lumen output is quite stable and no visible flicker.  They require a solid 24v input, and usually are sold with drivers from Lauren (which I didn’t do).

The E26 corn bulbs from 12vMonster come in a couple of varieties and numerous power/lumen/size levels.  These are designed for marine and RV use, and thus support a wide range of input voltages (12-24v or 24-36v or even wider).  As a result they have some sort of internal circuit that copes with the wide DC voltage.  Unfortunately that results in strange and awkward behaviours.  We found that the power draw of the ones I have vs lumen output is best at 15v.  They turn on at roughly 25% and reach maximum brightness at 50% (if run from 24v) or 100% (if run from 12v).  They handle 450Hz PWM, although some bulbs cause buzzing at 60-80% dimming, depending on the blubs and how many you have on the circuit… we just avoid the dimming levels that they buzz at and its not a problem.  There is one 2x3 bulb circuit where as they ramp from 0% to 100% you can hear the buzzing briefly as it passes through the range, but its just a minor oddity not a problem.  Oddly, the current draw (per unit time) goes UP at partial dimming levels causing an odd total power consumption curve that maxes out around 75%.  Again, this isn’t a big deal… except that the per-channel current draw is much higher than naively expected.  I fried a couple of 8A channels while learning that lesson, and blew a few fuses while experimenting.  The solution was to slave multiple channels together so that the load was spread evenly and the fuses per circuit are much lower than the 8A “fry level”.

Note that I tried 4-5 other sources of E26 bulbs (maybe more, memory fades) and these were the best.  By far, for all the reasons in my list of 8 factors.  Including others from the same retailer.  The bulb physical sizes also tend to be unfortunately large, so I ended up with the 9W ones from 12vMonster… they’re about an inch longer than I’d like but otherwise fine.  I have them behind diffusers in all fixtures, and with plenty of airflow.

As for the MR16s, I’ve ended up with their 4W (4x1W) 12-24v units (high K).  I’m using them to illuminate a kitchen sink, as well as a piece of wall art.  They are working very well for this, and they dim better than the corn bulbs.  I haven’t spent as much time fiddling with them as their current draw is much less and we’re only using 3.  I did have a different supplier’s MR16 over the wall art, however it flickered annoyingly and ran hot.  And during testing I had a couple of 7W MR16s from somewhere else, and one of them decided to overheat and destroy itself (not dimmed, just straight 24v despite being advertised as 24v capable!).  Needless to say those went in the bin.

I’ve had a running conversation with the founder of LumenCache.  He’s been spending a lot of time in China pushing manufacturers to develop decent low voltage DC PWM dimmable bulbs.  I’ve also suggested to Lauren a couple of times that they might find a market, but its outside of their usual model so I doubt they’ll try it.

Hope someone finds some of this useful!

   Andrew

[Seb]

Hi Andrew, can you tell us the DMX dimmer you are using/provide a link?

Thanks, Seb

[Skarsol]

The dimmer he's using is no longer available for sale for use with Loxone.