LED Strip overheating

[Hagopm]

Hello all,

 

I'm currently creating an RGBW LED strip lighting layout for my music studio.

 

I was doing some tests last night sending DMX from my laptop with a chamsys USB DMX dongle and the LED strip got very hot and then the red chips stopped working so I am trying to diagnose what is wrong.

 

This is the chip I have chosen:

https://www.ebay.co.uk/itm/5M-600LED-Non-Waterproof-Double-Rows-5050-SMD-RGBW-RGBWW-Flex-Led-Pixel-Strip/202178850090?ssPageName=STRK%3AMEBIDX%3AIT&var=502158507969&_trksid=p2057872.m2749.l2649

(This ebay listing does not mentioned power consumption but similar products on other pages are rated 28.8 watts per metre)

 

I'm planning to have 5 uplights each individually DMX controllable.

 

I've got this DMX decoder:

https://www.amazon.co.uk/dp/B075FHJM35/ref=asc_df_B075FHJM3554995331/?tag=googshopuk-21&creative=22146&creativeASIN=B075FHJM35&linkCode=df0&hvadid=232000808334&hvpos=1o1&hvnetw=g&hvrand=5864756536590440433&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1007235&hvtargid=pla-393438555055

 

and this power supply:

https://www.downlightsdirect.co.uk/mean-well-150w-led-driver.html?fee=3&fep=37596&gclid=Cj0KCQjwk_TbBRDsARIsAALJSObUFg2fersMov3waAAmI36IRknPYVlqmi6DVSHk9rITRWX6JcZOISwaAsrCEALw_wcB#description

 

I wired it all up yesterday putting 5m of strip on one DMX output and wiring the power supply into one of the 4 DC inputs.

Maybe this is where I went wrong?

Maybe I should have wired the power supply in parallel across the 4 DC inputs?

Just wondering what more experienced lighting people think went wrong?

I know that 5m of this strip = 150w power consumption and normally you oversize the power supply by 20% but I do not plan to use the full 5m, I plan to use 4 at the most. Again maybe this is where I went wrong driving the power supply too hard?

 

Opinions welcome.

[jonathanhill]

You have probably experienced thermal runaway. LED strip is usually designed to be fitted to a metal channel to aid heat dissipation.

[maeterlinck]

Most likely it will be more current draw than the PCB can handle. Try adding additional runs of cable from the driver to points along the tape. I would guess every 1.25m, or maybe 1m as you're wanting 4m total.

(This will obviously depend on what colours etc you use - all ON = more current draw)

[itiba]

Sorry if this is a silly question but the transformer is deffo 12v for your 12v tape? Meanwell are a pretty good brand but I always meter out before connection.

[Shez]

I know that 5m of this strip = 150w power consumption

Something doesn't sound right there - at 12V that's over 12A you'd be drawing through that tape. Well, more actually - 3 for each colour and 12 for the common. I'm not surprised it got hot if that's what's going on!

[Hagopm]

Sorry if this is a silly question but the transformer is deffo 12v for your 12v tape? Meanwell are a pretty good brand but I always meter out before connection.

 

DOH!!!

 

Its a 24v transformer and the tape is 12v.

 

So there's my problem. I ordered 24v tape before to go with the 24v transformer but the tape came with connection points incompatible with the DMX controller.

controller needs common, R, G, B, W and the tape came with GRND, +24V, R, G, B. So I ordered replacement tape and didn't realise I'd ordered 12v.

 

So I think what I will do is buy more 12v tape and swop the power supply for a 240w 12v version. Then I can use the full 5m of tape if I want to. Does that sound good to you guys?

 

Thanks for everyone's help on this.

 

I'm trying to find a UK supplier for RGBW 12v double row 5050 LED strip and it looks like a lot of it is wired Grnd, 12v+, R, G, B, so not compatible with my DMX controller.

 

Maybe I'm better off buying single row and using 180 degree connection clips to create a double row. I guess the end result will be the same. I don't want to wait 2 weeks for delivery. what do you chaps think?

[itiba]

The DMX decoder you have will run fine at 24v so as you have the transformer I'd go with 24v RGBW tape. You'll use less current for the same power so things won't run as hot.

 

ETA: if it's RGBW tape it'll have 5 contacts for RGBW and +24v so post a link to the tape you're looking at as there's a mistake somewhere.

One of you're music tech's must be good at soldering I imagine?

 

[Hagopm]

The DMX decoder you have will run fine at 24v so as you have the transformer I'd go with 24v RGBW tape. You'll use less current for the same power so things won't run as hot.

 

ETA: if it's RGBW tape it'll have 5 contacts for RGBW and +24v so post a link to the tape you're looking at as there's a mistake somewhere.

One of you're music tech's must be good at soldering I imagine?

 

 

Thanks Itiba.

 

I'm staying with 24v and have ordered 10m of single line tape that will arrive in 3 or 4 days. I've ordered some wired tape connector clips so I can do a 180 degree connection and I will double the rows myself and maybe triple them as I'm planning for each uplighter to only be 30-40 cm long. As this is 12mm wide tape I will also be able to use standard clip on connectors so less fiddly soldering that might fail once I take the tape off the bench and try to fit it to the cornice attached to the wall. My soldering is OK (I'm a one man show, no techs at my disposal) but I find the clips more reliable. My cornice has a recess of 40mm so I have space in there for 3 rows of tape with a small gap in between each.

 

This is how most of the 24v double line RGBW tape is wired that does not match up with the outputs on my DMX controller :

https://I.ebayimg.com/images/g/wh4AAOSwX5ZbEQ1h/s-l500.jpg

 

Fingers crossed this will get it all sorted!

[david.elsbury]

Power it from each end (and in your case, I guess the ‘middle’) to help minimise voltage drop along the tape too.

[timsabre]

The terminal labelled GND is actually the neg for the white. Pretend it says W and all will be fine

[Hagopm]

The terminal labelled GND is actually the neg for the white. Pretend it says W and all will be fine

 

Right!! My brother suggested that. Will try this tomorrow

[timmeh2]

Hi

 

I was always told that 24v LED tape dissipates more heat (and therefore requires better heatsinking) than 12v or the 5v stuff, simply because the resistors have to do more work to drop the forward voltage to what the chips need.

 

Happy to be proven wrong though...

 

All the best

Timmeh

[DrV]

Hi

 

I was always told that 24v LED tape dissipates more heat (and therefore requires better heatsinking) than 12v or the 5v stuff, simply because the resistors have to do more work to drop the forward voltage to what the chips need.

 

Happy to be proven wrong though...

 

All the best

Timmeh

No, the LEDs are connected together in longer strings (probably 6 rather than 3 for white ones) to increase the forward voltage drop of the LEDs so the drop across the resistors remains about the same. The big advantage of 24V tape is that for a given power it uses half the current so the supply leads don't need to be as thick, or, for a given length of tape, the LEDs at the far end are brighter.

[timmeh2]

Learn something new every day.

 

All the best

Timmeh

[timsabre]

In fact 24v tape does run slightly warmer as even with 6 leds the resistors are dropping more power.

 

On 12v tape 3x reds are about 7.5v and 3x greens/blues about 10.5v so the resistors drop 5.5v/1.5v. On 24v tape 6x reds are 15v, 6x greens/blues 21v so resistors dropping 9v/3v.