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I'm trying to follow this tutorial on Adafruit, which powers the Pi, and a 1 metre LED strip, through the GPIO using DC.

I'm not sure what power source to use as I'm not very experienced with this sort of thing. It needs to be portable so a simple 5V 10A switching power supply isn't going to fit the bill. Will a mobile battery pack such as this one work? As it has 5V / 9V / 12V 2A output and DC? Or am I massively oversimplifying things?

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The numbers you care about are "voltage" and "current" (and perhaps how long the power source would last, in the case of a battery). Voltage is measured in volts, and current in ampere (technically its the "maximum current flow").

You need a 5V 1.2A power supply for a PI (that's five volts, 1.2 ampere). For normal use 1A would also do great (I never found the requirement for 1.2A, even with multimedia). 10A is A LOT of current, way more than the PI can handle. It will work, just like a 1A supply, but its just an overkill and you would be wasting money.

Your battery, which gives out 5V and 1A is perfectly fine. But it won't be enough power to power that LED array.

You need to see how much current your LED array demands, and add that to the 1A the PI is going to take.

DO NOT plug anything that is above 5V, you could fry the PI. A higher voltage is BAD. A higher Ampare is good, but beyond 1.2A is not going to effect anything, unless you want to plug more devices at the same time, to that power source, then you need more current to go between them.

One more tip: A power supply should be regulated, so jumps in the power supply don't mean jumps in how many volts they are giving to the device. Many cheap power supplies (ones from ebay and such) do not have those regulators and give out 6V and not 5V as it says on their casing. Avoid "too good to be true" prices, there is a reason they are that cheap.

  • You mention in your answer that the battery won't supply enough power for the LED strip- but the tutorial says - "A 2 Amp power supply is sufficient for a 1 meter LED strip", the battery I linked to is 2 Amp and the 5v necessary? What's the issue with the battery? – Ben May 30 '13 at 23:27
  • You need 2Amp for the LED strip plus another 0.5Amp for the PI (you can get away with 0.5 if all its doing is switching LEDs). In that case 2Amp would not be enough. It might work. – GuySoft May 31 '13 at 9:40
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forget about the battery packs, you need just simple 5V 2-3A power adapter plug to power your strip.

actually, if I were you, I'd separate the power supplies, and use traditional RasPi power source to power the board, then another power supply just to power the LED strip, this way:

  1. Raspberry Pi is still fed through a polyfuse, that may protect it in case of shorts or unexpected surges.

  2. there are no large currents flowing across GPIO pins, just the control signals.

  3. whatever happens to LED strip won't hurt your Pi and vice versa.

  4. if you decide to go for a longer strip or totally different appliance, you don't have to rewire RasPI power supply.

  • How can this be made into a portable solution that the project requires? Everything will be mounted on the bike, there can't be any mains power. – Ben May 31 '13 at 14:21
  • @Ben Raspberry Pi is not generally intended for a portable solution. if you need just to control a few LEDs, you don't need USB/HDMI or Ethernet, please, choose a simple micro processor, and your power consumption will easily go from 700mA to a several milliamperes, maybe a hundred nanoamperes and you save a lot on batteries. – lenik Jun 1 '13 at 2:25
  • Very true, but the Raspberry Pi still definitely can do portable projects, as demonstrated in the tutorial itself. – Ben Jun 1 '13 at 17:38
  • @Ben RasPi is good to learn or do some prototyping, when you have convenient environment and plenty of computing power to spare, but the final product most always should use the smallest/cheapest hardware possible. – lenik Jun 2 '13 at 0:52
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I have found a solution to my power supply issue.

By using a simple lead acid battery with sufficient current and voltage coupled with an UBEC to step the current and voltage down to 3A and 5V respectively, I am able to power my Pi in a portable manner.

  • 1
    that seems a bit overkill when you can run for a couple of hours on AA batteries - learn.adafruit.com/battery-power-for-led-pixels-and-strips/… . If it's a push bike rather than motor bike I'd go for an mcu and AAs rather than a pi and carry lead around – Pete Kirkham Jun 4 '13 at 12:32
  • you can also check a pack of AA bateries or if you want to go fancy, get your self a racing drone battery, they are cheapper this days – lightshadown Jun 14 '18 at 18:33

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