Bypass 2 and LED issue

[Acidomoduso 0]

I have a small quandry...

 

I have fitted a dimmer 2 to an LED strip light. This has a transformer that used to be attached to a plug but is now controlled by a mains switch.

I am suffering from the dreaded "switch off and watch the light flash all night" syndrome.

 

I am aware that i have to connect my Bypass 2, however, the "bulb" isn't a bulb and the transformer is hidded behind plasterboard and insulation.

 

Is there ANY way i can connect the bypass to the switch end at all? I am aware it has to connect to the bulb end but this would mean cutting my ceiling open then repairing the damage. I'd rather not do this.

 

ANy solutions or advice will be welcome (however, i may know the outcome!!)

[Momos 103]

I highly doubt your setup can work at all.  If i understood correctly you have a let strip with a transformer, meaning the leds works on 12V.  You can not use a Dimmer 2 for this as you can not dim the transformer.  For this setup you need an RGBW device that is installed between the transformer and the strip.

 

 

[Acidomoduso 0]

Thank you for your reply.

Yes... i kind of thought so. I will probably use the dimmer on another light in the house.

 

However, as i said, the transformer is buried under plasterboard and would involve me cutting the ceiling open to reach the transformer. I could do this to install the RGBW device but it's just too much aggrivation and mess.

It is frustrating as we have just renovated the house.and i could have installed these things if i'd have known at the time. It was stripped to a bare shell!

 

Oh well... back to the drawing board.

[Momos 103]

Well sorry about that but as a general rule: never burry transformers or any other device in a place where you can not get to them.  Those transformers can break also.

 

 

[jakub.jezek 370]

@Acidomoduso, where is you Dimmer 2 located? Is it behind the switch?

 

In some cases you can add bypass directly to a Dimmer load output and Neutral, but it can still flicker.

 

Do you have access behind plasterboard to power supply?

[speedy 64]

On 8/23/2017 at 5:45 PM, Acidomoduso said:

ANy solutions or advice will be welcome (however, i may know the outcome!!)

 

If you have built in the dimmer and the power supply, (is that even legal in the UK?) there might be a solution.

From what you are saying i gather that you can dim the light but it doesn't turn off properly.

And there is no way of reaching the dimmer or the transformer (except for the LED strip)

 

If this is the case you could add load to the LED strip side. (A resistor)

 

So depending on what transformer you use (is it maxed out ex 10W to 10W strip then this won't work) you might add a resistor in parallel with the LED strip.

You then get a "base load" with the resistor and that might work in this special case.

 

So if you have 12V than a 24 Ohms resistor gives 0.5A and so 12V*0,5A = 6W as an example. (So the resistor needs to be able to dissipate 6W and the transformer has to have 6W in reserve)

This might need som tweaking when dimming the load "changes"  6V and 24 Ohm resistor is 0,25A.

 

And it might work with 48 Ohms so then there is only 3W.

This might work as an "ugly" hack as you said that any solution was welcome  

Edited September 4, 2017 by speedy

[petergebruers 1,268]

@speedy great thinking but I am 99% certain, adding a resistor as an extra load on the secondary side won't work. The "blinking" results from the capacitor at the primary side of the supply (dimmer side of the supply) charging up slowly (because of small current passing through dimmer and thus capacitor). When start voltage of the supply has been reached, it will start running and give out full power, until that capacitor depletes. Which may be a second or even a fraction of a second, but that is enough to visibly blink the LED. Then the cycle repeats. If you put some extra load on the *secondary* side (like your 24 ohm resistor), that doesn't change the charging cycle. It does change the discharge cycle, it will make the pulse shorter. But the LED will still blink. The Bypass is not a resistor. It is an electronic switch, which keeps the voltage on the capacitor below the starting voltage of the supply. That is why the bypass has to be installed on the primary side.

[speedy 64]

4 hours ago, petergebruers said:

@speedy great thinking but I am 99% certain, adding a resistor as an extra load on the secondary side won't work. The "blinking" results from the capacitor at the primary side of the supply (dimmer side of the supply) charging up slowly (because of small current passing through dimmer and thus capacitor). When start voltage of the supply has been reached, it will start running and give out full power, until that capacitor depletes. Which may be a second or even a fraction of a second, but that is enough to visibly blink the LED. Then the cycle repeats. If you put some extra load on the *secondary* side (like your 24 ohm resistor), that doesn't change the charging cycle. It does change the discharge cycle, it will make the pulse shorter. But the LED will still blink. The Bypass is not a resistor. It is an electronic switch, which keeps the voltage on the capacitor below the starting voltage of the supply. That is why the bypass has to be installed on the primary side.

 

Sure you are right, and i won't argue with the correct way of using Fibaro bypass  

 

I have been in situations where when you dim (or try to turn off) the lights they start to blink (to small current) 1W filament led lights for example without bypass.

Add some lights (load) and the blinking goes away without the bypass and dimming + on/off is possible.

 

So maybe in this situation (without possibility of reaching dimmer or transformer) added load to the transformer might stop the blinking.

It only blinks at a low dim level when he tries to turn off the lights.

We then go above the required minimum VA of the dimmer to be able to shut off the light without Bypass. (perhaps)

 

As a sidenote:

I use this as a added load (parallel to lights) and i can dim 1W 230V filament leds with Fibaro V2 dimmers.

Its actually a (transient) surge protector but it works well as a "bottom load" for the dimmer with my limited trials.

Please login or register to see this link.

 

 

Solution alternative 2:

A different solution is to install a RGBW device next to the LED stripe (drill a hole next to it if possible or maybe it can be hidden next to it) and control the RGBW device with S2 of the dimmer.

The dimmer is then set to 100% constantly, this might cause strange behaviour (if the RGBW device doesn't get 12VDC constantly) depending on the transformer (when the RGBW turns off the LED strip and load = 0W) but you asked for any solutions.

Not fantastic but will (might) work without ripping the ceiling open  

 

 

[petergebruers 1,268]

15 minutes ago, speedy said:

I use this as a added load (parallel to lights) and i can dim 1W 230V filament leds with Fibaro V2 dimmers.

Its actually a (transient) surge protector but it works well as a "bottom load" for the dimmer with my limited trials.

Please login or register to see this link.

 

It depends on the LED bulb (and 2-wire versus 3-wire dimmer setup, that is important too). I have about 15 different types and not all of them are happy with a "snubber". A bypass is expensive, but it works with all my bulbs. I know, I keep repeating myself... And I can assure you, I do not have anything to gain from this advice... no Fibaro shares or anything, I am an end-user... 

[speedy 64]

2 hours ago, petergebruers said:

 

It depends on the LED bulb (and 2-wire versus 3-wire dimmer setup, that is important too).

Very true,  always connect 3-wire if possible is my advice, that has never given me trouble.

 

 

2 hours ago, petergebruers said:

I have about 15 different types and not all of them are happy with a "snubber". A bypass is expensive, but it works with all my bulbs. I know, I keep repeating myself... And I can assure you, I do not have anything to gain from this advice... no Fibaro shares or anything, I am an end-user... 

Hehe, yes, its a good device the Bypass 2, no doubt.

I can also recommend it without question not having anything to do with Fibaro other than being an installer and user