My question: it's my understanding, based on the official Raspberry Pi FAQ, the wiki, and numerous forum threads on Stackexchange and elsewhere, that the Raspberry Pi has a 1.1A polyfuse on the micro-USB input, which limits the total current that the Pi+any peripherals can draw to 1.1A.
I understand that it's worth using a power supply slightly bigger than 1.1A because:
- you can get a more stable voltage by not stressing the power supply to its limits
- sizes like 1.5A may be more common than 1.1A, 1.2A etc; and 1.0A is too low
However, given the existence of the 1.1A polyfuse, I can't figure out the purpose of a 2A supply. I think I've even seen 3A supplies marketed. Unless I'm really missing something, there's no way to draw that much current directly through the Pi (not counting splitting the cable for some custom setup), and I have a hard time believing that you get any added "more stable voltage" benefits by moving up to 2.0A from 1.5A. So, are the companies selling these bigger supplies just wrong? Or is my understanding wrong?
You can see my email exchange with ModMyPi support about this in this thread on Reddit (scroll to the bottom; note that it doesn't look like they were really aware of the 1.1A fuse). I also started a new thread there and on the official raspberrypi.org forums, but this is my first Stackexchange post so it won't let me post more than two links.