armandesigner
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Raspberry Pi 3 B+ Power Supply

Fri Nov 30, 2018 5:23 am

Hello everyone
I just planned to buy a Raspberry Pi 3 B+ but I'm having a question.
Is it possible to connect a 5V with 1.5A or 2A to the raspberry pi?
Please tell me in details if it's possible.

drgeoff
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Re: Raspberry Pi 3 B+ Power Supply

Fri Nov 30, 2018 10:40 am

A PSU that can truly* provide 1.5 amps or more and maintain 5 volts will be OK for powering a 3B+ with ordinary USB keyboard and mouse. If you will be using USB peripherals which draw significant current you are more likely to see problems.

And be aware that an otherwise OK PSU can br rendered not OK by using a cable to the RPi that drops excessive voltage because it is too long, has wires that are too thin or uses wet string instead of real copper.

The official RaspberryPi 2.5A PSU is strongly recommended and is reasonably priced.

* Many PSUs, especially those intended for use as chargers, do not meet the specs implied by their labels.

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HawaiianPi
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Re: Raspberry Pi 3 B+ Power Supply

Fri Nov 30, 2018 9:42 pm

The recommended power supply is 5V and 2.5A, but that accounts for 1.2A to the USB ports, which leaves 1.3A for the Pi itself. So if you aren't planning on using the USB ports a 1.5A supply should work, assuming it's not crap quality or a phone charger (phone chargers are not recommended because they often have poor voltage regulation).

If you do need to use the USB ports, then 1.5A may not be enough, but 2A could suffice for USB devices that don't consume much power.

You really should just save yourself the headache and get an official Raspberry Pi Universal Power Supply. It's a proven performer, and usually pretty affordable (depending on where you live and who you buy it from). Click on the green BUY tag near the top of the page and scroll down.
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armandesigner
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Re: Raspberry Pi 3 B+ Power Supply

Sat Dec 01, 2018 11:17 am

HawaiianPi wrote:
Fri Nov 30, 2018 9:42 pm
The recommended power supply is 5V and 2.5A, but that accounts for 1.2A to the USB ports, which leaves 1.3A for the Pi itself. So if you aren't planning on using the USB ports a 1.5A supply should work, assuming it's not crap quality or a phone charger (phone chargers are not recommended because they often have poor voltage regulation).

If you do need to use the USB ports, then 1.5A may not be enough, but 2A could suffice for USB devices that don't consume much power.

You really should just save yourself a headache and get an official Raspberry Pi Universal Power Supply. It's a proven performer, and usually pretty affordable (depending on where you live and who you buy it from). Click on the green BUY tag near the top of the page and scroll down.
Thanks for your answer. What if we use a 5V with the 3A power supply? Will this damage the device or it will even help the process?

drgeoff
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Re: Raspberry Pi 3 B+ Power Supply

Sat Dec 01, 2018 11:43 am

armandesigner wrote:
Sat Dec 01, 2018 11:17 am
HawaiianPi wrote:
Fri Nov 30, 2018 9:42 pm
The recommended power supply is 5V and 2.5A, but that accounts for 1.2A to the USB ports, which leaves 1.3A for the Pi itself. So if you aren't planning on using the USB ports a 1.5A supply should work, assuming it's not crap quality or a phone charger (phone chargers are not recommended because they often have poor voltage regulation).

If you do need to use the USB ports, then 1.5A may not be enough, but 2A could suffice for USB devices that don't consume much power.

You really should just save yourself a headache and get an official Raspberry Pi Universal Power Supply. It's a proven performer, and usually pretty affordable (depending on where you live and who you buy it from). Click on the green BUY tag near the top of the page and scroll down.
Thanks for your answer. What if we use a 5V with the 3A power supply? Will this damage the device or it will even help the process?
Your question demonstrates your lack of understanding. A PSU needs to be able to deliver at least the current the load desires. Even if a PSU is able to deliver more current than that, the load will not draw more.

Brandon92
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Re: Raspberry Pi 3 B+ Power Supply

Sat Dec 01, 2018 12:28 pm

armandesigner wrote:
Sat Dec 01, 2018 11:17 am
Thanks for your answer. What if we use a 5V with the 3A power supply? Will this damage the device or it will even help the process?
If the output voltage of that power supply stays stable over all his load. Than that power supply is suitable for the task.

As a example your house wiring. That is "always a steady" 230vac* and is capable of delivering a certain power. If you connect one led lamp, no problem. If you add more than 100 led lamp and stay below the maximum power, still no problem. If you add even more led lamp, all the light will go out. And you need to replace a fuse.
In the case of the Rpi it can crash if that is the case.

*in my country

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rpdom
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Re: Raspberry Pi 3 B+ Power Supply

Sat Dec 01, 2018 12:39 pm

Brandon92 wrote:
Sat Dec 01, 2018 12:28 pm
As a example your house wiring. That is "always a steady" 230vac* and is capable of delivering a certain power.

*in my country
That would be unusual. Here in the GB the voltage can vary between about 220V and 250V. It depends on time of day, load on the system and distance from the premises to the nearest power substation.

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Burngate
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Re: Raspberry Pi 3 B+ Power Supply

Sat Dec 01, 2018 5:32 pm

From what I remember, the UK had nominally 240V AC, while the rest of Europe had settled on 230V AC.
Both were allowed to vary by a small amount, so some time in the last 50 years that small amount was enlarged, just enough for both sides of the Channel to be actually the same but labeled different.
So now, the UK is 240V (+10V, -20V) while you in the Netherlands have 230V (+20V, -10V)

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rpdom
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Re: Raspberry Pi 3 B+ Power Supply

Sat Dec 01, 2018 6:34 pm

Burngate wrote:
Sat Dec 01, 2018 5:32 pm
So now, the UK is 240V (+10V, -20V)
Yep, currently (or should that be "voltagely"? :lol:) 245V here. I haven't been to the Netherlands (yet! I have lots of friends there, so will have to visit them rather than them coming here again), but I'm sure it varies a bit.

Anyway we seem to have drifted off topic a bit, so I'll leave it at that.

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HawaiianPi
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Re: Raspberry Pi 3 B+ Power Supply

Sat Dec 01, 2018 8:12 pm

armandesigner wrote:
Sat Dec 01, 2018 11:17 am
Thanks for your answer. What if we use a 5V with the 3A power supply? Will this damage the device or it will even help the process?
5V/3A should work fine (assuming a good quality PSU). It won't harm the Pi (which will only draw the current it needs). However, it will not benefit a Pi 3B+ because the internal poly-fuse limits the current that can flow through the Pi. As long as the power supply can provide a stable 5V at up to 2.5A your Pi will be happy.

I have powered my Pi computers from a variety of sources, ranging from phone chargers to adjustable power supplies. Some worked great, others, not so much. The official Raspberry Pi Universal Power Supply is the least expensive solution that worked well for me.

If you are planning on using something you already have, then telling us what that is would help us better determine its suitability. The most problematic are phone chargers and power supplies that use a separate USB cable.

Standard micro USB cables often can't deliver much more than 500mA (0.5A) without voltage loss (the USB 2.0 power spec is 5V/500mA). You need a micro USB 2.0 cable designed for high current charging (charging cables included with high end smart phones and tablets may work).

Charging phone batteries doesn't require precise voltage control (a phone battery only needs a little over 4.2V to charge). I have a 5V/2.4A phone charger that dips well below 5V at only a 1A load (it charges my phone, but it's a lousy Pi PSU). That's not to say all phone chargers are crap power supplies. I have one particular charger that works great, but unless you can properly load test it, phone chargers are not recommended.

So, assuming your 5V/3A supply has good regulation, and your power delivery cable can handle the load, you should be fine.

And, of course, this assumes maximum load conditions. When your Pi isn't working hard, and you don't have the USB ports loaded too heavily, it will use much less power.
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Brandon92
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Re: Raspberry Pi 3 B+ Power Supply

Sat Dec 01, 2018 9:13 pm

Your are correct that the voltage is not exact 230Vac, that's way I wrote in between " ". To make my explanation a bit more easier to understand. The actual voltage in the Netherlands is 230Vac +/-10%.
My intention of that explanation is that it doesn't matter if you draw no power* or (close to) the maximum power* out of the power supply. As long if the maximum power that can be delivered is higher, that the power consume of the product itself.

*if the quality of the power supply is good. And the output voltage stays the same over the full range of the capable load. Also the wiring need to be able to deliver the power. And you don't loose to much voltage across that wire.

praxisp
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Re: Raspberry Pi 3 B+ Power Supply

Wed Jan 02, 2019 5:20 pm

Hello and happy new year to everyone!

I got a pi 3 B+ as christmas present and I tried to boot it with my original pi power supply(for pi 3B). I connected 2 usb peripherals (keyboard and mouse). The pi is showing the yellow thunder icon, meaning is not getting the necessary power supply... Will I need to buy a specific power supply for the pi 3 b+ ?

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marcosbong
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Re: Raspberry Pi 3 B+ Power Supply

Mon Jan 07, 2019 1:44 am

Happy New Year dude.
I'm just a newbie in this world, but have some knowledge on electronics and I'm pretty sure that the Raspberry Pi 3 doesn't need more than 1A to run the SoC. The main waste of power comes from what you plug in your USB ports.
I'm using an official PSU 2A for Rpi2 on my just new Rpi 3B+ with usb keybrd and mouse and I have no problems at all.
Make sure you're not using a power hunger keybrd or mouse.
If you mouse and keybrd have a reasonable power consumption, perhaps your PSU is faulty. The official PSU for Rpi 3 is very reliable as you can check in this comunity
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Imperf3kt
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Re: Raspberry Pi 3 B+ Power Supply

Mon Jan 07, 2019 1:57 am

Most likely issue is your operating system is outdated. You can make sure by checking that you are running Raspbian Stretch and opening a terminal, and running the commands
sudo apt-get update
sudo apt-get upgrade
From the Pi3b, before putting the card in the Pi3b+
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HawaiianPi
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Re: Raspberry Pi 3 B+ Power Supply

Mon Jan 07, 2019 2:29 am

praxisp wrote:
Wed Jan 02, 2019 5:20 pm
Hello and happy new year to everyone!

I got a pi 3 B+ as christmas present and I tried to boot it with my original pi power supply(for pi 3B). I connected 2 usb peripherals (keyboard and mouse). The pi is showing the yellow thunder icon, meaning is not getting the necessary power supply... Will I need to buy a specific power supply for the pi 3 b+ ?
If the Pi 3B+ is booting and showing the lightning bolt, then it's a power problem.
  • What are the make, model and spec's of your original power supply?
  • Does it have a built-in micro USB power cord, or does it use a separate USB cable?

If it's not booting and showing the lightning bolt on the color GPU test screen, then it's a problem with the firmware on your SD card. The newer 3B+ model requires a new kernel and new firmware to support the improved hardware. Trying to boot older firmware will result in the false low voltage warning and boot failure.

If your card has an older version of Raspbian Stretch you can update it in any older Pi model with:

Code: Select all

sudo apt update && sudo apt full-upgrade -y
and then it should work in the new 3B+ model.

If your version of Raspbian is older (Jessie or Wheezy) it's not compatible with the 3B+ and you must start over with the latest Raspbian.
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