When and why should I use a Fibaro Bypass? (Discussion)

[Ettrig 4]

Hi everyone! I am a bit confused about the Fibaro Bypass. Currently I run ~15x Fibaro Dimmer 2 in my appartment, and overall they seem to work well.. Right now I only have 1 Fibaro Bypass installed, and I am confused, cause reading the instructions, it feels as though I should need more of them.. ?

 

The loads I connect are a mix of types.

• MR16 12V LED bulbs (driven by 0-70W trasnformers) 
• E14 LED-bulbs 230V
• Downlight Dimmers (in ceiling) with own transformers
• 24V LED strips connected to 230->24V Dimmable LED Transformers (70W)

 

Dim low (0-50W)

Reading the manual, the Fibaro Dimmer should only operate 50+ W without bypass. That said, I have tried to run with and without Bypass, and I notice no difference in how low I can get with the dimming.. 

Does anyone really notice a difference in how low you can dim using a bypass, and then connected to what?..

 

Voltage Drops

I did run into some problems with the Dimmer connected to 24V-LED Strip setup to report "voltage drops" and my suspicion there was that it was because it had no N connected to the dimmer itself. In that situation I connected a Bypass, and it seems those voltage drops went away. 

 

Fluctuating Light Intensity

The only issues I've really had are with are the E14 LED bulbs and also with the Downlight Spotlights in the bathroom.

When I dim them low, they have a tendency to "fluctuate" a bit in intensity, which can be annoying.. It seem to only occur when it's dimmed to the lower % and my solution has been to increase "minimum" for the Dimmer. That said, I'd love to be able to dim lower with a "solid" intensity.

 

Can someone explain a bit more WHY and WHEN a Bypass should be used?..

To me there seems to be 2 situations

 

When you don't have a N in your wall, using a Bypass helps feed the dimmer with current "backwards" through the Load?

 

If you want to run super low energy LED bulbs that can't be properly turned off because of the super low current always flowing through the Load?

(That said, if you have N connected to the dimmer, the above shouldn't happen?)

 

Would love to have some elaboration here. I think the manual to the Fibaro Bypass and general information about it could be very much more detailed to help consumers decide whether to use one or not..

(Perhaps it could even be integrated into the calibration procedure of Home Center with some questions helping to figure out when you configure a new device whether you should connect a Bypass or not)

 

 

 

Edited April 30, 2021 by Ettrig

[Tim__ 114]

For me, I use a bypass when the load is below 50W (which is most of the time).  And always use a neutral to avoid extra issues.

 

As for fluctuating light intensity, the fact that you see it only with some lights should tell you that it is a bulb problem. The drivers in those bulbs may not be of the best design.  Working out which ones work can be a trial and error challenge. 

[Ettrig 4]

17 hours ago, Tim__ said:

For me, I use a bypass when the load is below 50W (which is most of the time).  And always use a neutral to avoid extra issues.

 

As for fluctuating light intensity, the fact that you see it only with some lights should tell you that it is a bulb problem. The drivers in those bulbs may not be of the best design.  Working out which ones work can be a trial and error challenge. 

 

Do you see any improvement in diming for loads below 50 when you use a Bypass?.. As you write, most of the loads go below 50W, (especially when working LED etc), but from my experience it has been fine dimming low without the Bypass (which makes it so confusing..) From reading the manual, going below 50W shouldn't even be possible?..

 

[Tim__ 114]

From memory, using the bypass helped reduce flickering at low dimming levels. But I believe it depends on the driver in the bulb. You must have good ones - which bulb brand do you use?