GU10 Lamp Recommendations - Fibaro Dimmer 2

I have 11 Fibaro Dimmer 2 modules installed that control downlights in each room. Apart from one room ALL of my downlights are dimmable models that have integral LEDs rather than a replaceable lamp. The Dimmer 2 supposedly analyses the connected load and calibrates the module accordingly but I've had mixed results. In most cases the dimming is not linear - it starts slow then speeds up (if the retractive switch is held). I find that if I set lights to 1% level they're at about 25% actual brightness. I only fit decent kit and many of the lights are Collingwood Haler H2Pro models. I also have Aurora and Robus.

Can anyone using Dimmer modules recommend any standard GU10 lamps that they've found to work well with regard to dimming as I've decided that anything with integral LEDs is destined to fail. Thanks.

I find my dimmer 2's and Collingwood h2 Pros work great, I have 8 dimmer 2's on H2 pros with between 4 and 10 leds on each.
I have some Phillips gu10s on dimmer 2's and I would say the Collingwood are better.
I have 32 ledvance zigbee gu10 rgbws as well as a couple of hue gu10s and the Collingwood dim better than them.

Have you played with the fibaro settings?

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@garyburchell That's interesting. Maybe I need to look at them again. The lights I mentioned that won't dim low enough aren't Halers. I've messed with the settings to a point - mainly the timing of a dimming step and percentage of dimming step. I had a few issues with the drivers for the Dimmer 2 so once calibrated all of the parameters were adjusted manually using the Basic Z Wave Tool before switching back to the Hubitat driver. I saved all the parameters to a spreadsheet. I've tried them with and without a bypass. When calibrated from the Z Wave Tool, the logs show calibration without bypass regardless of which parameter is sent so I'm not sure what's going on there.

I've got 12 of the older (push fit bezel) H2 Pro in the living room. They cause the Dimmer 2 to shut down if ran at 100% and I've had to set the minimum higher than ideal, otherwise they don't all come on or light up popcorn style over 10 seconds. The lower the dim level, the less teh difference. 25 is quite bright, 10 a slight difference, 1 is not much different to 10. Elsewhere I have 4 of the H2Pro 550's in both a bedroom and bathroom and 6 of the newer H2Pro 700's in the Kitchen.

I think the best dimming I get is from some Philips WarmGlow 3.8W GU10's on the landing. I'd happily use the Halers everywhere if I could get them right, but it's a big cost outlay to fit them if they don't dim low enough or the calibration prevents them running at 100%.

Quick reply as SWMBO is giving me the look.

I dont use the hubitat driver I use a mix of cjcharles driver for the ones I don't need scenes and Robin Winbourne if I need scenes.

I'll give u a better reply later :+1:

Cjcharles driver is available via HPM and Robin's driver is here

I haven't ever noticed the none liner dimming, but saying that I cant remember the last time I use the retractive switch for dimming as all mine auto dim with the outside lux.
I just had a play with dimming via switch and sill can't see it.
All mine are H2 550's and 3 years old Installed with a complete rewire, I have no popcorning on any of mine.
There is a slight delay between pressing the switch and them turning on but it's like 0.5 seconds at best.

Thanks @garyburchell

I'll take a look at those drivers. I've just checked and I was originally using the ericm driver. I had some issues early on with that (when I was brand new to Hubitat) which is why I set mine up manually with the Basic Z Wave Tool once calibrated. I think in my use case, the driver is not so important once the module is set up, as the dimming parameters are saved in the module itself.

When calibration is run on the module either by command or using the B button, it automatically sets a minimum and maximum level. For my lounge with 12 Halers it has automatically set parameter 1 (minimum) to 11 and parameter 2 (maximum) to 70. So the dimming range of 1 to 100 on Hubitat equates to 11 to 70 actual range. That bit is shown below:

Did you use the Bypass with yours? I've not witnessed any flickering and couldn't see any difference between having them installed or not.

It's been a while I know i bought 15 bypass to go with the 15 dimmer 2s. But I'm pretty sure same as you it didn't make a difference, so I don't think I have any fitted. I just fitted one recently on a 7 watt b22 bulb and I didn't use one there.
All mine are installed using the 3 wire method.
I let the auto do its thing as well and for me it works and I'm happy with the result,i think I remember reading somewhere that setting doesn't change after it's completed.
Have u adjusted the soft start? All mind are set to no soft start.
I read some where that Collingwood leds have a huge current draw when first turned on so this can help if you set it to .2 or .5.

I would say it is because the driver might change you values again. I think the one you're best to use is in Hubitat package manager and got fixes/ enhancements from me, Eric and @cjcharles . In the driver you can ask it to set itself up again and you can update the values so they stay correct.

I have 4 or 6 switchable white collenwood down lights depending on the area, I put a bypass on them all (I wasn't really need for the 6 area but it doesn't do any harm when you would be teetering on edge).

All LEDs have what's called "inrush" depending on the quality of the driver this can be crazy high. But it's for micro seconds. We have tested 30w LED panels with 70A inrush each.

I assume you mean phase and neutral? Always best to have a neutral on a dimmer, it requires one no matter what it's just ones without a connection for it take it through the light, that's why if you load is too low the lights don't turn off.

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Yes I've made a point of learning never to touch the configure button after I've set up the parameters manually, so they never change themselves.

I was originally using Erics driver but not the modified one in HPM. The issue I always had with both that driver and the Hubitat one, was that the switching parameter would not store. I'd set it up for momentary, but would find after a couple of operations that the light would stay on. It could only be turned off by pressing and holding in the retractive switch (so it was open circuit switch, lights on and closed circuit switch, lights off). When interrogating the parameters using the Basic Z Wave Tool I found that parameter 20 was changing to 1 (toggle) when I had it set to 0 (momentary). I've now just downloaded the driver you mention so will set one up again using that driver.

I'm struggling to see the need for the bypass. I understand it can prevent flickering and stop any residual glow from the LEDs when off with low loads. I've only an issue with the latter on my garage lights (a pair of LED bulkhead fittings). I fitted one in there to cure that. The rest of them have been fine - all are 2 wire as there is no neutral at the switch. Some rooms have the bypass and some don't but I tried with/without and didn't see a discernible difference.

Never experienced this? How old are your dimmers the firmware hasn't changed for years so I doubt it's that unless yours are really old.

If they are fine and you have a neutral they are rarely needed mine were just on the threshold of recommended min so I put them in just incase.

I have one old one on 3.2 firmware. That's unaffected as it's used with a toggle switch (non dimmable load). All the others are version 3.5.

There is no neutral present at the switches. All are wired 2 wire with a link placed between the neutral connection and Sx as below:

Yeah 3.5 is still the latest as to my understanding. I actually have a fibaro hub if it comes to that.

What's the load of your lamps? If the load is not enough to power the device that would explain the lack of status.

Everything works. I've had most of the Dimmer 2s running for nearly a year now. It's just that the dimming performance of the lights connected to them thats a small niggle - the minimum level is not dim enough and they don't ramp up very evenly (only a marginal difference when changed from say 10% to 30% level. The Collingwood Haler H2Pro are 8.5W per fitting with a power factor exceeding 0.95.

I started the thread as I was just wondering whether I'd get better dimming with replaceable GU10 LED lamps as opposed to dimmable integral LED downlights. After all it's cheaper to replace a GU10 than an all in one fitting.

This is prime example of lack of neutral. Try a by pass recalibrate and see if you get a better range.

How many?

100% don't do this. Unless your looking to change to halogen lamps (why would you). A dedicated driver is a much better product, just think of it like this. The driver on you LED currently is a box on a gu10 that driver is sweezed into that tiny end cap of the lamp. They don't last as long due to the heat and the reduction of kit to make it work.

As a spark and engineer I would disagree with the last comment aswell, yes years ago it was cheaper to buy a GU10 housing and a GU10 than a full unit (I used to recommend it) but that's not true any more. Unless your buying crap and there is a lot of that out there, it's not cost effective because they last a year if your lucky.

I have tried them with/without bypass and recalibrating each time but not noticed them to be noticeably better/worse. In fact when reading the parameters the presence or lack of bypass made no difference to the minimum/maximum levels set by the calibration. I don't think there's anything at fault - just that the minimum level of LED is not low enough for my liking.

One annoyance I have noticed is that if you view the logs while sending the force calibration command Parameter 13 - it makes no difference whether you send value 1 (without bypass) or value 2 (with bypass), the log shows it received value 1 (never 2). Without doing it manually from the B button I can't be sure whether calibration with bypass is being carried out. However I'll just add the bypass where they are not fitted (I think I have them in most rooms but have lost track)

I think in one of the rooms I did get a neutral to the switch (rather than link N to Sx). Is the bypass ever needed if a dedicated neutral is used?

It varies. Living Room has 12 (too much of a chew on to split into two circuits due to the switching arrangement). Bathroom and Bedroom have 4, Kitchen has 6.

Happy to follow that advice - I thought similar.

It's never been my main line of work but I am qualified and have been working in the field since the 80's. I never buy crap and would always go for recognised quality brands - GE, Philips etc (rather than some of the rubbish in Toostation/on Amazon). Still I think there's quite a difference in cost. A Collingwood Halers with Bezel is around £25 whereas a decent quality GU10 housing and separate lamp would save around a tenner per unit. I get your point though.

The problem with the all in ones such as Halers is they keep changing the design. The bezel design, lens appearance, lumen output, angle and colour have all changed over the years. I have had several failures and it's less hassle to replace 6 lamps to make them all match than buy 6 new all in ones.

I have a single 6 watt led bulb running off a dimmer 2 with a 3 wire set up and no bypass all is good

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It gives a better range with the neutral and the minimum load comes down but it can still help if your near the minimum. Think of it like this: I think the range is 250W? That means it's can dim 250w from 1% to 100% that's fixed. So when you put a 20w load on it, it's still trying to dim 1/100 of 250. So yes the smarts in it take a snapshot of the load and adjust its parameters to try and knock of the top and bottom but there is only so much it can do if your sitting on its extreme. So the bigger the load or the addition of the snubber helps. Also I found although again it's bluddy cleaver to work out it's min and max it's not perfect, so I got it to calibrate with the correct settings in the driver. Then once it found them I had to manually knock back the min a bit to get more dimming, but I had the snubbers so was able to do that without any I'll consequences.

The 4 maybe but the rest especially the 12 should not need the bypass. If the 4 doesn't have a neutral I would definitely have one on there though. The 12 should be perfect dimming in that range.

The switchable white Collingwood ones I have used to be about 11/12 but I just brought some for my sister and think they were about 17/18 (■■■■ COVID and component shortage). They come with the bezel and a connection box really recommend them for domestic. Haven't paid £25 range for years, most are around the 10-20 mark, but yeah I agree the lower end of that is usually the GU10 mark. I only used to recommend that because I knew they would only last a few years (even medium quality ones) but the price was coming down and quality going up all the time back then so it didn't make sense in paying 30-40 a device when they would only last a few more years at best. Would tell the customer these will last a 2-4 years if you're luckily but in that time a GU10 will be £4 replace them yourself and they will last few years again and you still spent less that buying the good stuff at the time. Then once the price comes down on the dedicated ones then change them out. I was bang on with my prediction in the end.

Yeah halers were the "big" brand makeing all the promises at the time of 7 years and easy swap. I knew it would never work because the technology was so new and changing so fast. Hence why I used to say the above. For me with dedicated ones I haven't had that issue now, I have had some drivers go (had one the other day at in-laws ) but A the company sent a new one no quibble and B it's just the driver so no changes. If you lamps are good quality realistically you should never need to change that part. The driver will go a few times before that.

That's well below the minimum and you will shorten both the lamps and dimmers life cycle even if it is working.

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@BorrisTheCat - Great info, thanks.

So is the requirement of the bypass based solely on the load, or is it a must if there's no dedicated neutral present, regardless of the load? The info in the Fibaro full manual is a bit ambiguous when I read it and their forum wasn't a lot of help.

I've never found the H2Pro's any cheaper than about £24 (with a bezel and including VAT). I'd be interested I where you're getting them for less than £20 (unless that price is down to your spend with a wholesaler)

The lounge with 12 is the most problematic (no dedicated neutral). I've had to raise the minimum level set by the calibration to 11. Otherwise I can dim them all the way down from maximum without issue, but if I turn them off at that minimum level then back on again - I'll only get a few of the lights come on until I raise the dim level a bit when they'll all come back. Those are the oldest ones though (the original ones with push on bezel) so maybe they just don't perform as well.

OK :+1:, I just made the assumption that if it worked it was ok.
Best go an find those bypasses

Do u have a link/or can you explain as to why, I'm not disbelieving you just interest in why.

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