pi3 amperage with overclock + fan + 4 players + N64
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I'm 99% sure that there is no official 3.0 A charger for the RPi.
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Hi, finally my charger arrived, the specifications are:
Charger :
Brand: dyf
Model: LA-530
Input: 100-240VAC0.3A 50/60Hz
Output: 5V 3000mACable :
E214382 AWM 2464 22AWG 80ºC 300V vW-1 AWM I A FTI LFIt works, and this is the official seller with an image of the circuits (I opened the charged and yes, it´s the same circuit as the photo):
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It works, and this is the official seller with an image of the circuits (I opened the charged and yes, it´s the same circuit as the photo):
lol... the image at the bottom looks like a doge meme...
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So true hahaha
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The Pi 1 and Pi 2 and Pi 3 all have a thermal resettable fuse (aka polyfuse) on the power supply connector and on the USB ports.
The max power you are guaranteed to be able to draw into a Pi 2 is 2A, and the fuse is rated to blow at 4A, it may blow below 4A especially if left for a period of time to degrade. The same applies to the Pi 3, but its current hold is 2.5A and the fuse blows at 5A or earlier.
You might be able to draw more current, "overclocking" the polyfuse if you want to call it that, but those are the figures the polyfuse is rated to pass reliably.
The most power you can draw thru the USB ports is 1.2A, though the Pi 2 comes configured at 600mA by default and requires
max_usb_current=1inconfig.txtto enable 1.2A USB.If you are doing big overclocks, or powering more than 1.2A over USB, you should power all USB peripherals with a powered USB hub.
The 5V GPIO is passed thru directly from the power connector, so you are limited by the power supply and by the polyfuse there.
The Pi 1 models have pathetic power ratings like 750mA polyfuse and are not well suited for big-current tasks.
The Zero has no current protection. I spose you could draw power thru it until you burn out the trace in the PCB.
The power problems most people have is that many power supplies cannot supply their max rated volt/current. For example, an 2.4A iPad charger will happily supply 5V at 2A, but starts to drop down to 4.75v and below once you increase current draw past 2A.
So over-rating the power supply (3A, 4A) ensures your power supply stays in its efficiency range, but you are never guaranteed to actually get that much current past the polyfuse.
All this and more at: https://github.com/superjamie/lazyweb/wiki/Raspberry-Pi-Power
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Thx for the technical comment, much apreciated!
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So if I'm reading this correctly, the Pi 3 can't draw more than 2.5 amps unless there's a short? Then why are people saying to get a 3 amp power supply?
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For overclock (more amp-demand) but under their risky decision:
"The power problems most people have is that many power supplies cannot supply their max rated volt/current. For example, an 2.4A iPad charger will happily supply 5V at 2A, but starts to drop down to 4.75v and below once you increase current draw past 2A"
"So over-rating the power supply (3A, 4A) ensures your power supply stays in its efficiency range, but you are never guaranteed to actually get that much current past the polyfuse"
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Yup, what @flop said.
A polyfuse is an electronic component with a thermal compound inside. It heats up as more current passes thru it and eventually the material inside separates to break the connection. Once blown, let some time pass (hours/days) and the material settles down again and current will flow again.
The polyfuse on the Pi 3 is rated to current hold at 2.5A and blow at 5A.
This means you can draw 2.5A thru the fuse all day every day. However, once you exceed that 2.5A, the fuse will start to heat up past the temperature it's intended to operate at and may eventually break the connection. This might take a day or a year or maybe your individual fuse will gladly pass some larger figure like 3A forever.
Once you hit 5A the fuse is guaranteed to blow. Realistically, the fuse will probably heat up too much and blow before reaching 5A.
You can also artificially cool a polyfuse (such as with a heatsink and fan) to increase the amount of current it can pass reliably.
The component marked 204L at F1 in http://i.imgur.com/q0LW5BK.png is a 2A polyfuse on a Pi 2.
People who hate polyfuses either desolder them and replace them with a bridge or large 0-ohm resistor, or just bridge over the top of them like this: http://raspi.tv/wp-content/uploads/2012/09/polyfuse.jpg
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People who hate polyfuses either desolder them and replace them with a bridge or large 0-ohm resistor, or just bridge over the top of them like this: http://raspi.tv/wp-content/uploads/2012/09/polyfuse.jpg
Apparently they don't even like them enough to bypass them with a decent solder joint. ;)
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