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Strobing problem on LED tape lights...

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Sorry dog

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First off, glad this place is here, and I'll appreciate any advice.

I'm sort of an electronics dummy, who knows just enough to be dangerous... but anyway here's my issue....

I've got a cabinet lit by 4 8ft LED strings (12V) and max current is about 3.5 amps.

I'm using a 150watt driver like this one https://www.amazon.com/Ledwholesale...sbs_328_2?ie=UTF8&refRID=1K0AFSTCR1VDBEKB7SH5

It works fine at max voltage but at lower light levels there is sometimes quite a noticable strobe effect. I was guessing that since it is dimmed before the driver, the voltage cuts off on the peak voltage levels off the sine wave, the output capacitors on the driver were running out of power before the next cycle. My wild guess solution was to add another capacitor or two between the output and light, so I put in a 10,000 microF 25V capacitor... . Problem is the only effect was to drastically dim the lights and little effect on strobing and adding a second capacitor parallel or series only makes effect more pronounced.

Can somebody try to explain my error or help me learn why this doesn't work?

Any suggestions on how I might fix the issue....short of buying another driver. I have another similar setup on another cabinet with the same problem, so trying to understand what's going on here.

Thanks for you time, Hunter.
 
Try a different dimmer. I'm guessing it is the dimmer that doesn't like the inductive load...
 
Could be the dimmer, but consider this,

This dimmer is a legrand adorne wireless unit that is supposed to work with ELV or MLV dimmable transformer. Now it could be the dimmer is bad, but I also have the same problem on another cabinet with similar setup using a more basic standard dimmer.
 
Does the dimmer have a minimum load requirement? You are running it at less than 30%.

ak
 
Does the dimmer have a minimum load requirement? You are running it at less than 30%.

ak
Do you mean driver? No, min current.

Dimmer said it has to have a load to start up but doesn't specify how much.....anyway the dimmer seems to work ok. Just get theflickering or strobing at around 20 to 60% partial brightness levels. Since the other cabinet with similar setup does the same thing, I tend to think it probably has more to do with the setup rather than a failing part.
 
Adding a big cap only makes it flicker slower as the transformer mutual inductance dominates and leads the current phase to shut off the triac after voltage firing at a low variable leading phase angle.
A secondary dimmer would work better or add a small 8~12W bulb rated for 24V as a dim preload or a 300W 120V halogen bulb on 12V as a low constant current load.
 
Oscillating around the holding current requirements may better explain the relaxation oscillator effect of flicker.
Adding a small fixed load such as a dim filament bulb is ideal solution of required size to permit lower dimming of the non-linear diode load.

Dimmers must be designed especially for LED's to work offline.
 
there are RF remote dimmers for led for less then $5 and they work I know I have them all over the house. And they are programmable to 25% 50% or 100% and can flah bounce glitter all kinds of way for $5 and are 2' by .5" why the super cost for something that simple as a dimmer? 2 WIRE IN 2 WIRE OUt GET WITH THE PROGRAM
 
there are RF remote dimmers for led for less then $5 and they work I know I have them all over the house. And they are programmable to 25% 50% or 100% and can flah bounce glitter all kinds of way for $5 and are 2' by .5" why the super cost for something that simple as a dimmer? 2 WIRE IN 2 WIRE OUt GET WITH THE PROGRAM

I get what you are saying, but unfortunately that kind of setup would defeat the system here. A portion of the lighting here is on an Adorne wireless system that has a wireless central control box that can be operated over the internet. I have done exactly what you are talking about on some lights, but some lights really need to stay on the automated system... when you have 5 or 10 remote controls to operate every night... well I think you can see the problem. Also, I'd rather not have to chuck several expensive drivers to go to another transformer that is more compatible, even if it is cheaper.

Anyway, I did try a RF wireless dimmer here and the driver and the dimmer unit did not get along very well. Lots of random blinking out. A non-dimmable transformer would probably would better if I went this way.

I also tried a halogen bulb to see if that would even out the load. 20 watts did not improve the strobing much, but then I bumped it to a 50w bulb which did show considerate improvement even if not perfect. Only problem now, is that if I keep that setup, now I have to hide a 50 watt heat source under the cabinet in an enclosed space. There will be a trap door to get to it, but still not very easily or quickly. It's probably 4 or 5 cubic feet of space, so not worried about fire levels of heat, but still don't like that situation for heat and power waste reasons. I also just tried a large resistor of 20 ohms which resulted in about the same improvement. The drawback there of course being I won't have the higher brightness level available, but it's rarely needed. The lights spend 99.9% of their time at 25%.

Is there a way to make the original idea of using a capacitor to smooth out voltage drops ... i.e. another rectifier bridge to isolate the capacitors from the driver or something.

Thanks again for the advice.
 
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