LED spot polarity

[zwiller]

I have some 12V led spots as in this thread: You are not allowed to view links. Register or Login

One brown wire, one blue.  No matter how I wire them they turn on...  I didn't expect that.  Is this OK?  Does it not really matter?

MANY THANKS!

[tbone321]

With those wire colors, it looks like these spots were set up to work with either DC or AC current and has a bridge rectifier to make the conversion to DC which is required by the LED's.   Most DC only devices use Red and Black to identify the correct polarity.  The bridge doesn't care which way you connect it to DC because either way, it sends the output in the required polarity.  As long as you are not exceeding the expected voltage, you should be fine.

[zwiller]

Great.  Thanks tbone!

In another thread a member asked about a constant current driver for the leds in the spot.  I thought the design of the DSC was basically 3 channels of MR16 which WAS constant current.  Do you see any issues running spots (10W) off a DSC?  Even 3 connected is only 2.5A.  Just concerned, since I brewed up the idea to use DSCs for these spots and wondering if I missed something.  Preliminary testing is good.  Plan to run so long term/heat tests to see how how the DSC fares...

[tbone321]

The DSC is not going to care as long as the total current draw doesn't exceed 4A.  The only issue that you may have is if the spots are dimmable or not.  Some of them have circuitry inside of them such as DC to DC converters which do not respond well to dimming.  I would look into that and if they can be dimmed then you are good to go.  If not, then you may still be able to use them with the DSC but you need to be very careful not to dim, either on or off only and I would also set one up as a test and hammer it for a while to make sure that it holds up to the output from the DSC. 

[zwiller]

Although I didn't do a lot of long ramps/dimming I did do plenty of short ones and they survived all of last season.  I shot an email to Ray Wu and asked him if they are indeed dimmable.

What will happen if I ran some dimming torture tests and it is no dimmable?  Fry the led/light or fry DSC?

[keitha43]

Well I do know that some led strings I bought from a well known vendor a few years back that had switched manufacturers and after ramping them up an down after awhile the rectifiers started overheating which caused the lights to go very dim. Slicing open the rectifiers showed scorching and dead capacitors and such.  Some rectifiers even caught fire. I rebuilt my own rectifiers as I thought the lights themselves looked better than the replacement strands the vendor offered to replace them with. I won't name the vendor as I am sure he never would have sold them if he knew there was a problem with dimming. My guess is the circuitry he mentioned may do the same.

[zwiller]

That's encouraging, I was worried I could fry the DSC. 

I just bought them and hooked them up to a MR16 and didn't think much about it... 

[zwiller]

Do connected lights flash (as SSC) when programming a DSC?  I assume they don't...  Kinda weird I didn't read that anywhere.  In any event, it works I just don't get the exciting strobe of success.   

Anyhoo, using xlights I have the spot on a level of 3 for about a half hour now.  They dim quite well and no magic smoke or heat to touch.  I am actually feeling the pcb and parts not just the light.  Do I need to vary ramp up and down or is this suffice?

[tbone321]

If they didn't cook already, you are probably in good shape.  As always, the longer you test the better but it looks good for you so far.  If you used these lights already with an MR16, then there should be no issues at all.

[Steve Gase]

Although I didn't do a lot of long ramps/dimming I did do plenty of short ones and they survived all of last season.  I shot an email to Ray Wu and asked him if they are indeed dimmable.

What will happen if I ran some dimming torture tests and it is no dimmable?  Fry the led/light or fry DSC?

If you have problems, it would be with the LED/light. 
As long as you don't short the wires, the DSC would be fine.  The fuse on the hub is intended to protect you from shorting and overload.

[zwiller]

Ran the spots a few hours and no heat or issues at all.  Cool. 

Am I right the DSC does not flash connected lights during programming?   

[arw01]

Sorry I don't remember either, the SSC V4 certainly flashes white.

I am pretty sure the dsc did not, because I specifically flashed the test firmware to see if they were working and got not flashes until I powered up the DSC now that I think about it.



Put that as 95% certain they do not when programmed.

Alan

[twooly]

Mine all flash a blue when I program them.

[rm357]

Reloading the firmware does not cause flashes.

When programming the start channel and other parameters like string length and color order, the flashes let you know that the data has been stored in the device.

The SSCs need to be unplugged from the hub and plugged back in to reset the string.

[tbone321]

Ran the spots a few hours and no heat or issues at all.  Cool. 

Am I right the DSC does not flash connected lights during programming?   

The DSC does flash the lights when you configure it but IIRC, it doesn't flash all of the outputs and it may just flash output 3.  If you don't have anything connected to that output then you will not see it.  Either way, if it is accepting the start channel that you set it to, who cares.