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I bought a kit off ebay that came with an SMD 5050 RGB LED strip, an IR controller and a 3A PSU. Long story short, I have a second srip on its own and instead of buying the same PSU, I'm wondering if I can use a higher amperage PSU (5A) to power the strip so it can be brigher essentially. The ebay item is here.

What I'm sceptic about is that (while not listed on the ebay page specifically) the strip is rated for 2A each colour, and the IR controller is also rated for <2A each colour.

In my mind this makes sense as when using all colours, the 5A is distributed across the three colours using ~1.6A each. Sweet. But what happens when I run just a single colour, say blue? Does the 5A all go into that single colour potentially frying stuff or does the excess get grounded or is it even pulled from the wall at all?

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  • \$\begingroup\$ Hi, It is not possible to increase the brightness by opting a higher amperage PSU. It is like putting many apples in a plate. But, the person(LED strip) can eat only one apple(rated current at PSU output voltage) at a time. \$\endgroup\$ – Umar Sep 30 '15 at 6:36
  • \$\begingroup\$ @Umar while this is true, wouldn't the length of the strips affect the brightness in relation to the amperage? Theoretically say you have a 1A PSU for 1M, the brightness would be dimmer if we had 5M at 1A correct? Then bump it up to a 5A PSU it would brighten the entire strip up? That's my basis for adding more amperage as I believe 3A isn't enough current to supply the amount of LED's that are in a single 5M strip to their maximum potential. \$\endgroup\$ – SteppingHat Sep 30 '15 at 6:39
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Typical LED strips have fixed current usage, due to the 3 diode + 1 led setup. A PSU with a higher current capacity will not change this. It would only allow you to power a greater length of led strip.

If you have issues with brightness at the end of a long run of a led strip, this is due to the high resistance of the copper FPC used. The main way of getting around this, is to feed the power at both ends, at the middle, or every few meters.

Attempting to power a given length of LED strip with a supply that cannot provide that capacity, will result in a burned out PSU.

Edit: Of course, your strip is the 150 RGB leds per 5 Meters. That's 50 3-Led segments, 0.02A per segment, or 1 Amp per 5 meters, per color. Your strip only needs a 3 Amp supply. The typical 2 Amp per color strips have 300 leds per 5 meters, twice of what you have. Led strips come in all sorts of configurations, and the number of leds per meter is one of them, as well as led type/size.

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  • \$\begingroup\$ So in theory, the 3A PSU that I got as part of the package will have an extremely high chance of burning out with this particular strip and I'm better off with the 5A PSU? \$\endgroup\$ – SteppingHat Sep 30 '15 at 8:31
  • \$\begingroup\$ The supply would likely have inbuilt over-current protection, which would stop it burning out. It just depends on the design. If it doesn't, it could begin to smoke. \$\endgroup\$ – HandyHowie Sep 30 '15 at 8:48
  • \$\begingroup\$ @SteppingHat if the strip you are using requires 5A and you use a 3A psu, then yes, it can burn out, or act weirdly. \$\endgroup\$ – Passerby Sep 30 '15 at 9:21
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    \$\begingroup\$ @SteppingHat of course, your strip is the 150 leds per 5 Meters. That's 50 3-Led segments, 0.02A per segment, or 1 Amp per 5 meters, per color. Your strip only needs a 3 Amp supply. \$\endgroup\$ – Passerby Sep 30 '15 at 9:22
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If each colour needs 2A and you have 3 colours, then ideally you need a 6A power supply for full brightness at all times. A 10A power supply of the same voltage wont make them any brighter.

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  • \$\begingroup\$ Where would the extra amperage go? Is it even drawn from the wall to begin with? \$\endgroup\$ – SteppingHat Sep 30 '15 at 8:34
  • \$\begingroup\$ It is never drawn from the mains supply. \$\endgroup\$ – HandyHowie Sep 30 '15 at 8:46

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