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I'm working on mounting LED strips to my entertainment set up and part of it involves mounting strips to the back of my TV. I want to power the LEDs via a USB port found on the back of my TV. I'm limited to 5V and my question is how much of the strip can I use without worrying about significant voltage drop? Please note I'm a novice at this and I'm looking to get some hands on experience. Any suggestions or advice would be helpful. Thank you.
These are the specs of what I'm working with.
LED:
* Led Strip
* Color: RGB
* 5 Meters
* LED Type: 5050 PLCC-6 SMT SMD LED (IP65 Waterproof)
* LED Quantity: 300 leds/5 Meter or 60 leds/Meter
* Size: L500cm (5M) x W1.4cm x T0.3cm
* Working Input Voltage: 12VDC
* Output power: 72W /5 Meter
TV:
Height- 29.9 inches
Width- 57.7 inches

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  • \$\begingroup\$ All the LED strips I've seen are connected in parallel so you needn't worry about voltage drop. The main concern is the amount of power you can supply. Typically USB ports give ~500mA @ 5V = 2.5W so keep that in mind. \$\endgroup\$ – Doodle Apr 5 '16 at 7:09
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Voltage drop is not your major problem. Much more important is how much POWER your LED strips require vs. how much power is available from the USB port. It seems unlikely that your USB port will provide enough power for your LED strips. You must do the research to know how much your LED strips need. And how much is available from your USB port. Remember also that most LED strips are designed to run at a higher voltage than the 5V available from USB.

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  • \$\begingroup\$ Plz give ur led power constraints \$\endgroup\$ – chandan Apr 5 '16 at 5:37
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Considering the perimeter of any given tv, you shouldn't be worried about voltage drop. My tv is 43 inches. 2 feet high, 3 wide. Border wise, that's only 10 feet. 3 meters. And since it's a box, you can easily power both ends of the led strip to ensure voltage droop is reduced to nothing.

If your really asking how much you can draw from the usb port, then you need to look at your tv manual, and how much current your led strip requires. We don't know either of that.

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    \$\begingroup\$ LED strips are typically 1.5W per foot per color (and are also 12 volts)... so 10 feet = 15W (45W if RGB) which is way too much for USB. This simplifies his project greatly, as he can drop the impossible USB requirement and use common off-the-shelf power supplies, controls and amplifiers. \$\endgroup\$ – Harper Apr 5 '16 at 2:56
  • \$\begingroup\$ @Harper there are 5V strips, and you're assuming 60 led p/m 5050 RGB... What about 30 led p/m strips? Single color? 3258? 5630? 24 volt strips? etc. You're assuming too much that OP has not provided. \$\endgroup\$ – Passerby Apr 5 '16 at 4:07
  • \$\begingroup\$ No. My exemplar was 3528 monochrome @ 1.5 w/ft, yes @ 60 LEDs/metre. Triple that for 5050 RGB, and you're probably going to want RGB for backlighting a TV. Cut it in half for 30 LED/metre. Do the math and you see where things get hopeless real quick. LEDs are efficient but USB is limited. Gadgets are supposed to negotiate for >100ma, most ports can only give 500ma, some can give 1000ma and few (tablet chargers) can give 2000ma. \$\endgroup\$ – Harper Apr 5 '16 at 9:48

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