Having trouble with your lights not dimming, or having issues with fading or flickering during dimming/once dimmed? Let’s take some time and discuss the issue;
Although many LED lights state they are dimmable, the difference between two dimmable LED lights can be vastly different. Why is this, I hear you ask – well let’s investigate.
I have two 9W LED downlights on my workbench from different manufacturers. These are driver on board fittings, with a flex and plug, allowing it to plug into a ceiling mounted light outlet. Now both of these light fittings are described as being dimmable with no specified dimmer identified. What we are going to do is test these fittings with 6 commonly used dimmers and Stitchy. To simplify things from here we will call these light fittings Light (A) and Light (B)
FYI: The lights and dimmers used in these tests are irrelevant; it’s the outcome that is important.
RESULTS Light (A)
Dimmed well on two dimmers, fair on three, not on one and was irregular on Stitchy. This fitting flickered on two of the fair units and faded in and out on one fair unit. With regards to Stitchy, the dimming wasn’t smooth and only small movements on the app were reflected as big movements with the fitting.
RESULTS Light (B)
Dimmed well on four dimmers, fair on two, not on one and was good on Stitchy. This fitting flickered on two of the fair units during dimming up and down but appeared stable once dim level was reached. With regards to Stitchy, the dimming was smooth and consistent with the fitting.
Why did we get the varying results above?
To explain, LED chips are simply the light source and the driver provides a variable DC voltage output on a constant current bases to the LED chips!
LED chips come from only a few main suppliers, which allows them to be relatively constant in performance. The drivers on the other hand (regardless whether on-board or remote), can be manufactured by pretty much anyone anywhere in the world and in most circumstances are tested against the dimmers available in that location. LED drivers have an AC voltage input range of around 170 to 240v AC and will provide a DC voltage range matched to the Led Chip along with a fixed Milliamp output matched to the LED fitting. This is known as a Constant Current driver and reflect a huge majority of LED Downlights.
The components used and software available in any LED driver will dictate how good, how compatible and how flexible the driver is with various dimmers. Stitchy is classed as a dimmer and M-Elec has taken every step possible to ensure it is a flexible and adaptable dimmer, suited to the majority of lights.
The $2780 light that couldn’t dim properly
Interestingly, in recent times, we have found that price is not a guide for a quality, dimmable light fitting. For example, I recently came across a $2780 LED light fitting that had been installed over a kitchen bench. The customer was told this was a quality light fitting and that it would dim extremely well, but when installed and attached to a good quality standard rotary dimmer, it flickered, and after a period of time switched off completely. The dimmer was replaced by two other dimmers but this did not fix the problem. The customer then wanted to try Stitchy to see if it would be any different – not the case. Further investigation revealed the fitting was a quality fitting, but the drivers used were random and imported – with really poor dimming characteristics. As these drivers were integral to the light fitting and no suitable replacements were available, the light remains an on/off, non-dimmable fitting.
Not all lights will dim in all situations. Please take the time and check, please confirm with the manufacturer of any specialised light fittings. Let them know what dimmer you intend on using so they can test prior either for you or on behalf of your customer.
Wayne Crookes – Product Support