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I want to use 5 meters 5050 RGB Waterproof 300 LED Strip + 20 Key Music IR Remote Controller Sensor. Is it okay if I use a 12V 6A Power Supply?

Jacob
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phil
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  • Current consumption of an LED strip is dependent on length. – uint128_t Jun 25 '16 at 15:09
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    [Possibly useful](https://electronics.stackexchange.com/questions/19413/why-doesnt-my-5050-led-strip-draw-as-much-power-as-i-expect?rq=1) – uint128_t Jun 25 '16 at 15:10
  • A little bit of googling, and I found this: An article explaining how to chose the correct power supply for an LED strip: http://www.ledlightsworld.com/page.html?id=38 – Alex Jun 25 '16 at 15:56
  • There are too many possibilities with just "5050 LED" as the spec. I think my answer is correct - and it precisely matches the calculator you provided for the individual LEDS they are using. IF by 300 LEDS you means 300 emitters with 3 per pkg = 100 pkgs then my answer is about right. BUT you can get 5050 LWDA at many times that current rating - not usually in LED strips though. Please provide more information. – Russell McMahon Jun 25 '16 at 16:05
  • I'm talking about this [link](http://www.ebay.com/itm/271912880248?_trksid=p2060353.m2749.l2649&var=570747928192&ssPageName=STRK%3AMEBIDX%3AIT) 5 meters strip – phil Jun 25 '16 at 19:43
  • The trouble is that the link you have provided gives absolute no useful data about the characteristics of the LEDs. If you want accurate numbers, buy a product with a datasheet. Or try asking the supplier. We aren't tech support for eBay sellers. – uint128_t Jun 25 '16 at 20:39
  • @uint128_t I agree that lack of data is undesirable BUT seeing how to work out what needs working out and what is involved in doing so is a useful exercise with lessons for others and in other areas. – Russell McMahon Jun 26 '16 at 01:24
  • @RussellMcMahon Fair point. Nice answer :) – uint128_t Jun 26 '16 at 02:25

2 Answers2

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The manufacturer or supplier should specify current per length of strip.

As a "rule of thumb" most small LEDs are rated at 20 mA and groups of 3 are connected in series plus a series resistor to 12V. So approximately power dissipation for N LEDs =
Power = V x I = 12V x 20 mA x N/3 = 80 x N mW.
And I = 20 mA x N/3

For N = 300
Power = 80 x 300 mW = 24 Watts
& I = 20 mA x N/3 = 20 x 100 mA = 2A.

The two answers differ.
I think this one is correct :-).
I'll check the ratings of some 5050 LEDs but I think the other answer may not have allowed for the 3 LEDs per package.

Russell McMahon
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  • This is correct for 12V 5050 led strips which are near universal in their specs. 2 A Per channel of 100 3-led segments. The newer types vary based on the diode size used, as the packages may be the same but some have higher internal diode counts or shapes. Two 5630 strips can be completely different. – Passerby Jun 25 '16 at 19:55
  • I'm talking about this [link](http://www.ebay.com/itm/271912880248?_trksid=p2060353.m2749.l2649&var=570747928192&ssPageName=STRK%3AMEBIDX%3AIT) 5 meters strip – phil Jun 25 '16 at 19:57
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The datasheet of 5050 LEDs says forward current is 60mA at 3.6VDC.

60mA * 300 pcs = 18000mA or 18A at 3.6VDC.

In addition you must calculate wasted power in resistors and in wiring of the strip. It's hard to say how much power it uses without knowing what kind of LED strip it is, and how it's designed.Does it have input voltage of 12V? Or do you have to bring the voltage down?

BufferOverflow
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    LED strips usually use multiples of 3 LEDs plus a resistor across 12v. So IF each LED drew 60 mA you'd get 60 mA x 12V per 3 LEDS or 6A for 300. BUT a 5050 pkg in a LED strip probably has 3 x individual LEDS in the pkg rated at 20 m each or 60 mA the 3 in parallel or 20 mA in series. Which gives the answer I gave. He needs to give more information. Can you provide a link to the LED you cited? – Russell McMahon Jun 25 '16 at 16:08
  • I'm talking about this [link](http://www.ebay.com/itm/271912880248?_trksid=p2060353.m2749.l2649&var=570747928192&ssPageName=STRK%3AMEBIDX%3AIT) 5 meters strip – phil Jun 25 '16 at 19:55