Macbeth100
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Maximum RPi 3B+ Current Draw?

Thu Jan 10, 2019 3:11 am

I've found several different quoted figures for maximum current draw when the Model 3 B+ is under full load (all peripherals connected, etc.) but get quite varying values. When finding a 5V power supply for the Pi, what current capability should we specify? Is 1A enough?

Thanks

klricks
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Re: Maximum RPi 3B+ Current Draw?

Thu Jan 10, 2019 2:17 pm

Macbeth100 wrote:
Thu Jan 10, 2019 3:11 am
I've found several different quoted figures for maximum current draw when the Model 3 B+ is under full load (all peripherals connected, etc.) but get quite varying values. When finding a 5V power supply for the Pi, what current capability should we specify? Is 1A enough?

Thanks
You won't' find an exact number because it depends on the type, brand, model of each of the connected devices.

Generally 1A is not enough.

The RPi 3+ board is protected by a special fuse which permits no more than 2.6A. If the user attempts to draw more than that then the RPi will become unstable, crash, reboot etc.
Unless specified otherwise my response is based on the latest and fully updated Raspbian Buster w/ Desktop OS.

fruitoftheloom
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Re: Maximum RPi 3B+ Current Draw?

Thu Jan 10, 2019 4:56 pm

Macbeth100 wrote:
Thu Jan 10, 2019 3:11 am
I've found several different quoted figures for maximum current draw when the Model 3 B+ is under full load (all peripherals connected, etc.) but get quite varying values. When finding a 5V power supply for the Pi, what current capability should we specify? Is 1A enough?

Thanks

Just buy the Official PSU:

https://www.raspberrypi.org/products/ra ... er-supply/

https://www.raspberrypi.org/documentati ... /#pi-power
Retired disgracefully.....

Macbeth100
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Re: Maximum RPi 3B+ Current Draw?

Thu Jan 10, 2019 10:35 pm

I'm using the Pi with a battery (along with a voltage regulator) so can't use mains-connected powerpacks. I was looking at this previously which seemed to say that the baseline with no peripherals maxes out at around 980mA https://www.pidramble.com/wiki/benchmar ... onsumption. Is it necessary to spec a 2.5A power supply if I'm running a setup with just the standard Pi touchscreen LCD (which uses approx. 400mA)?

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Imperf3kt
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Re: Maximum RPi 3B+ Current Draw?

Thu Jan 10, 2019 10:45 pm

Macbeth100 wrote:
Thu Jan 10, 2019 10:35 pm
I'm using the Pi with a battery (along with a voltage regulator) so can't use mains-connected powerpacks. I was looking at this previously which seemed to say that the baseline with no peripherals maxes out at around 980mA https://www.pidramble.com/wiki/benchmar ... onsumption. Is it necessary to spec a 2.5A power supply if I'm running a setup with just the standard Pi touchscreen LCD (which uses approx. 400mA)?
You can use a lower specced supply if you desire, but you need to ensure it delivers the current it says it does, as the vast majority don't.
Note that a 1A rated PSU delivering 0.98A to a Pi will get VERY hot, and may not be rated for 1A continuous, instead 1A momentary.

However, according to the FAQ, Max power draw without accessories (for a Pi3b) seems to be about 1.34A, but you need to be seriously pushing the Pi to use that much power.
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HawaiianPi
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Re: Maximum RPi 3B+ Current Draw?

Thu Jan 10, 2019 11:01 pm

The 2.5A recommended for the 3B/3B+ models includes 1.2A for the USB ports, which leaves 1.3A for the Pi3 itself.

So 1.3A should be enough if the PSU has good voltage regulation, and that assumes no accessories. Anything on the USB ports, or any added HATS or other accessories need to be included in the power budget. As stated above, 1.3A is worst case, fully loaded, so you might be able to get away with less if the system is not going to be pushed hard (and if you're not maxing it, you might consider a more power frugal model).
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Macbeth100
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Re: Maximum RPi 3B+ Current Draw?

Thu Jan 10, 2019 11:11 pm

Sounds good, thanks for the help everyone

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