Keeping 250w of LED permanently dimmed
Discussion
I have a rather large set of LED lights which come to 250 watts on the same circuit (50 x 5w 240v dimmable LED bulbs). It's rather bright! They are controlled through a wifi switch for on/off.
I want to dim these lights down to something like 20% of brightness (precise value not very important). But finding a dimmer which can do this is tough. Most dimmers aren't rated for 250w of LED. The several expensive high-power LED dimmers I have tried (trailing edge etc). default to being "off" when the power is turned on from the wifi switch, as they are sophisticated little devices.
I've also tried a wifi dimmer, but they default to 100% brightness when turned on, rather than the "last dim-ness".
Does anyone know of a simple low-tech LED dimmer which will default to being "on" and last dim-ness when power is provided? Or is there any device which will cut the power to 20% (non-adjustable), suitable for LED lights?
I want to dim these lights down to something like 20% of brightness (precise value not very important). But finding a dimmer which can do this is tough. Most dimmers aren't rated for 250w of LED. The several expensive high-power LED dimmers I have tried (trailing edge etc). default to being "off" when the power is turned on from the wifi switch, as they are sophisticated little devices.
I've also tried a wifi dimmer, but they default to 100% brightness when turned on, rather than the "last dim-ness".
Does anyone know of a simple low-tech LED dimmer which will default to being "on" and last dim-ness when power is provided? Or is there any device which will cut the power to 20% (non-adjustable), suitable for LED lights?
The Varilight V-Pro range has a 300W option & comes on at the last brightness (set by the knob). Could you wire one of these in series with your wi-fi switch?
https://www.varilight.co.uk/dimmers/v-pro.php
https://www.tlc-direct.co.uk/Products/VLMJP300.htm...
https://www.varilight.co.uk/dimmers/v-pro.php
https://www.tlc-direct.co.uk/Products/VLMJP300.htm...
does it have to be that particular wifi switch?
lightwaverf do an inline dimmer that can do 250w of led, and it has adjustable dimming curves to suit different bulbs.
it can be paired to a wifi link.
you can also split the circuit and fit 2 and pair them in programming if you want a bit of headroom, I dont like running power electronics flat out, a bit of headroom is a key to longevity.
I'm sure lutron has something that would work too.
lightwaverf do an inline dimmer that can do 250w of led, and it has adjustable dimming curves to suit different bulbs.
it can be paired to a wifi link.
you can also split the circuit and fit 2 and pair them in programming if you want a bit of headroom, I dont like running power electronics flat out, a bit of headroom is a key to longevity.
I'm sure lutron has something that would work too.
Andeh1 said:
That's the most insightful thing you could say on a Friday evening, in a forum designed for helping people?
It's fairly typical from this poster, must get some sort of weird satisfaction from been a dick. That he managed to string more than 5 words together has impressed me though. It'll never be a helpful reply, too much to ask. If it's a permanent option OP, if my experience of temperamental dimmers for led bulbs in a chandelier are to go by. Would it be worth putting a physical tint onto the lenses to reduce the output? Your electric usage would reflect this, but all dimming options so far I have found a bit flaky.
250w of LED's are a lot of LED's
You are wanting the 20% level to be kept as the default, and that is the issue with electronic dimmers and not being able to set a default level. It may be possible to set up a power supply to meet your requirements. A good analogue power supply will keep giving out the same voltage when turned on. so would meet your requirements.
Now the issue is getting this sorted and set up.
The lamp cluster - what voltage is it operating from ? how is the cluster of lights fed ?
Say for example the voltage was 24v and at full brightenss of 250w thats around 10A or there abouts... 24v at 10A ? hefty...
Now thing is your saying down at 20% it wont be drawing that amount of current. But voltage regulation usually results in heat being produced. so it would need to be a switchmode to make it more efficient and hopefully drop the power being dissipated.
Something that takes in mains and puts out 24v that can be adjusted, using say a variable resistor so that when the power is put off and back on it comes on at the previous set level. electronics are good b ut n othing beats old fashioned variable resistor settings.
So to help I need some info -
Voltage of the fitting - and how its connectcted at present.
and we can take it from there
You are wanting the 20% level to be kept as the default, and that is the issue with electronic dimmers and not being able to set a default level. It may be possible to set up a power supply to meet your requirements. A good analogue power supply will keep giving out the same voltage when turned on. so would meet your requirements.
Now the issue is getting this sorted and set up.
The lamp cluster - what voltage is it operating from ? how is the cluster of lights fed ?
Say for example the voltage was 24v and at full brightenss of 250w thats around 10A or there abouts... 24v at 10A ? hefty...
Now thing is your saying down at 20% it wont be drawing that amount of current. But voltage regulation usually results in heat being produced. so it would need to be a switchmode to make it more efficient and hopefully drop the power being dissipated.
Something that takes in mains and puts out 24v that can be adjusted, using say a variable resistor so that when the power is put off and back on it comes on at the previous set level. electronics are good b ut n othing beats old fashioned variable resistor settings.
So to help I need some info -
Voltage of the fitting - and how its connectcted at present.
and we can take it from there
Your problem is going to be the start up current / power.
Whilst LED's have a great low power consumption when running the issue is starting them.
Traditionally standard DL lamps get down rated by 10-15% to keep them withing power-ratings of dimmers etc.
In the early days of LED's they used to have a down-rated by 80-90%. I don't know if that is still the case or they have improved, but even if they have improved to 50% then you still have to allow for your 250w's of LED to need 500w's of capability to cope with the start up.
Whilst LED's have a great low power consumption when running the issue is starting them.
Traditionally standard DL lamps get down rated by 10-15% to keep them withing power-ratings of dimmers etc.
In the early days of LED's they used to have a down-rated by 80-90%. I don't know if that is still the case or they have improved, but even if they have improved to 50% then you still have to allow for your 250w's of LED to need 500w's of capability to cope with the start up.
Your problem is going to be the start up current / power.
Whilst LED's have a great low power consumption when running the issue is starting them.
Traditionally standard DL lamps get down rated by 10-15% to keep them withing power-ratings of dimmers etc.
In the early days of LED's they used to have a down-rated by 80-90%. I don't know if that is still the case or they have improved, but even if they have improved to 50% then you still have to allow for your 250w's of LED to need 500w's of capability to cope with the start up.
Whilst LED's have a great low power consumption when running the issue is starting them.
Traditionally standard DL lamps get down rated by 10-15% to keep them withing power-ratings of dimmers etc.
In the early days of LED's they used to have a down-rated by 80-90%. I don't know if that is still the case or they have improved, but even if they have improved to 50% then you still have to allow for your 250w's of LED to need 500w's of capability to cope with the start up.
It’s not necessarily low tech, assuming your drivers/lights run smoothly at 20%, you could do this with Rako which has a setting to turn on to a certain scene (level per circuit) when power is restored.
We had several modules in a previous property that for reasons I won’t bore everyone were switch controlled for on/off but then had dimming/scenes controlled via the app. The modules for those circuits were trailing edge dimmer retrofitted into the ceiling void on the switched side of the circuit. You might need to split into 2-3 circuits (can’t remember what the max power handling is). Each module circa £100, bridge (to programme and control) about £500?
Another property we have a similar number of DLs in our kitchen, again Rako controlled but spread across four circuits to handle more complex scenes. That one runs from a home run feed to the main lighting control centre.
There may well be simpler/cheaper solutions out there but if you draw a blank and want to throw money at it... it’d get more complex I expect if you wanted to them be able to change the levels via a different app/system but I took from the OP that the desire was to have *the* level be 20%.
We had several modules in a previous property that for reasons I won’t bore everyone were switch controlled for on/off but then had dimming/scenes controlled via the app. The modules for those circuits were trailing edge dimmer retrofitted into the ceiling void on the switched side of the circuit. You might need to split into 2-3 circuits (can’t remember what the max power handling is). Each module circa £100, bridge (to programme and control) about £500?
Another property we have a similar number of DLs in our kitchen, again Rako controlled but spread across four circuits to handle more complex scenes. That one runs from a home run feed to the main lighting control centre.
There may well be simpler/cheaper solutions out there but if you draw a blank and want to throw money at it... it’d get more complex I expect if you wanted to them be able to change the levels via a different app/system but I took from the OP that the desire was to have *the* level be 20%.
Why not just try a standard 60-400VA rotary dimmer switch. We have varying results with all sorts of LED's and dimmers, sometimes a standard dimmer works perfectly on 6 LED's and other times we cant get some to work properly no matter what combination we use.
Why have you got all 50 on one switch though? As VEX said they have quite a high inrush current when starting up, they all have a mini transformer inside them along with capacitors, inductors and other components as part of the PSU and these are quite inductive when quite a few are switched on together.
We wired a pitched roof extension the other week which can't have been more than 3 meters square and the lady wanted 20 downlights fitted in, all on one switch. She then pointed to the gable and said I've got a security light to go up there as well, I sarcastically said oh ok, inside or outside.
Why have you got all 50 on one switch though? As VEX said they have quite a high inrush current when starting up, they all have a mini transformer inside them along with capacitors, inductors and other components as part of the PSU and these are quite inductive when quite a few are switched on together.
We wired a pitched roof extension the other week which can't have been more than 3 meters square and the lady wanted 20 downlights fitted in, all on one switch. She then pointed to the gable and said I've got a security light to go up there as well, I sarcastically said oh ok, inside or outside.
I'm still not clear why the V-Pro dimmer in series with the Wi-Fi switch wouldn't do the job. That particular dimmer has a rotary knob to set the brightness combined with a push-on/push-off action to turn the light on & off.
I have one in a bedroom so I did a test: I pushed the knob to turn the light on & set it to a low brightness, then I dropped the lighting MCB & the lights went out. When I reset the breaker (to simulate the wi-fi switch) the lights came back on at the previous low level. Now I suppose it's possible the wi-fi switch & the dimmer might not play together nicely but it's cheaper to try it than run around installing Hue lamps & alternative control systems.
I have one in a bedroom so I did a test: I pushed the knob to turn the light on & set it to a low brightness, then I dropped the lighting MCB & the lights went out. When I reset the breaker (to simulate the wi-fi switch) the lights came back on at the previous low level. Now I suppose it's possible the wi-fi switch & the dimmer might not play together nicely but it's cheaper to try it than run around installing Hue lamps & alternative control systems.
Sheepshanks said:
Mr Pointy said:
I'm still not clear why the V-Pro dimmer in series with the Wi-Fi switch wouldn't do the job.
I don't know what the issue is - maybe start-up current? - but one thing is the V-Pro says up to 30 lamps and the OP has 50. The lights are on a festoon string (good quality, decent cable), so no question of making into a pair of circuits. And I'd rather not replace the bulbs if possible!
I wasn't aware of the inductive nature of switching on LEDs (thanks VEX), but that's presumably why lots of the higher-power old-tech dimmers aren't rated for LED.
But since Mr Pointy has kindly done the "will it default to on" test, I'll get the V-PRO first, and see how it copes with 50 bulbs. Thanks everyone!
xyz123 - good point that changing the bulbs is an option - they are arty LED ones, so Plan A is to avoid replacing them. If a £20 dimmer solves the problem, then that's good.
Edited by biggiles on Sunday 28th March 20:26
Edited by biggiles on Sunday 28th March 20:28
Edited by biggiles on Sunday 28th March 20:48
LooneyTunes said:
It’s not necessarily low tech, assuming your drivers/lights run smoothly at 20%, you could do this with Rako which has a setting to turn on to a certain scene (level per circuit) when power is restored.
We had several modules in a previous property that for reasons I won’t bore everyone were switch controlled for on/off but then had dimming/scenes controlled via the app. The modules for those circuits were trailing edge dimmer retrofitted into the ceiling void on the switched side of the circuit. You might need to split into 2-3 circuits (can’t remember what the max power handling is). Each module circa £100, bridge (to programme and control) about £500?
Another property we have a similar number of DLs in our kitchen, again Rako controlled but spread across four circuits to handle more complex scenes. That one runs from a home run feed to the main lighting control centre.
There may well be simpler/cheaper solutions out there but if you draw a blank and want to throw money at it... it’d get more complex I expect if you wanted to them be able to change the levels via a different app/system but I took from the OP that the desire was to have *the* level be 20%.
One of the other key reasons for splitting your room into 3 or 4 circuits is to manage start-up / in-rush current.We had several modules in a previous property that for reasons I won’t bore everyone were switch controlled for on/off but then had dimming/scenes controlled via the app. The modules for those circuits were trailing edge dimmer retrofitted into the ceiling void on the switched side of the circuit. You might need to split into 2-3 circuits (can’t remember what the max power handling is). Each module circa £100, bridge (to programme and control) about £500?
Another property we have a similar number of DLs in our kitchen, again Rako controlled but spread across four circuits to handle more complex scenes. That one runs from a home run feed to the main lighting control centre.
There may well be simpler/cheaper solutions out there but if you draw a blank and want to throw money at it... it’d get more complex I expect if you wanted to them be able to change the levels via a different app/system but I took from the OP that the desire was to have *the* level be 20%.
I love Rako, use it a lot on projects but it, as will most dimmers, is limited to 10 or 12 lamps per circuit. But you dont need a bridge to program it, only to run the app and voice integration
Keypads (wireless light switches) and circuits are around £130 RRP per part, less if you know who to ask. Quite a bit more for the bridge.
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