fjr
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p2 powersupply specs?

Wed Feb 04, 2015 8:57 pm

What are recommended powersupply requirements for pi 2?

If the pi 2 is a server with no usb hard drive?

If the pi 2 is a server with a 2tb usb hard drive?

If the pi 2 used with peripherals, pc mouse, keyboard, etc and no usb hard drive?

If the pi 2 is used with peripherals, pc mouse ... and a 2tb usb hard drive?

Thank you.

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DougieLawson
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Re: p2 powersupply specs?

Wed Feb 04, 2015 10:04 pm

Use 2A. The RPi2 will draw whatever current it needs.
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klricks
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Re: p2 powersupply specs?

Thu Feb 05, 2015 2:14 am

fjr wrote:What are recommended powersupply requirements for pi 2?

If the pi 2 is a server with no usb hard drive?

If the pi 2 is a server with a 2tb usb hard drive?

If the pi 2 used with peripherals, pc mouse, keyboard, etc and no usb hard drive?

If the pi 2 is used with peripherals, pc mouse ... and a 2tb usb hard drive?

Thank you.
Not possible for us to answer directly because you did not give the specifications of each device.
Here is how to figure this out for yourself:
The maximum current into the RPi is limited to 2A.
The maximum current to all of the USB ports combined is 1.2A so that leaves 0.8A for the RPi + anything connected to the GPIO's

You need to find the current draw specification of each USB device and add them up. If <= 1.2A then you should be OK as long as your power supply can deliver the power needed and still maintain the 5V +-5% voltage. If > 1.2A then you will have to use a powered HUB.

Note the default USB power output is 600mA. You must change a configuration setting to get the max 1.2A

So as mentioned you can't go wrong with a 2A supply. A smaller supply can be used for the server with no peripherals.
A larger than 2A supply can be used but has no added benefit.
Unless specified otherwise my response is based on the latest and fully updated Raspbian Stretch w/ Desktop OS.

fjr
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Re: p2 powersupply specs?

Thu Feb 05, 2015 4:55 pm

DougieLawson, I did not intend to send a personal message to anyone. If I did then I apologize.

Maybe someone can explain how my post at the same time could get posted on the forum, because how else could klricks read the post and answer?

Thank you for your answer.
I should have described the hardware setup more precisely. There are power supplies called hdd power supplies. They are 2amp and the voltage output is 12v 5v molex.
That should be enough for pi2 and keyboard and pc mouse and a camera.

A 2tb sata hard drive is 0.5amp? I would like to take a hdd power supply, connect a molex splitter to the power supplier. A molex splitter that splits into a power sata connector and a micro usb connector. Then connect the pi 2 and the hdd to the hdd power supply. And use a sata to usb adapter to connect the hdd to the pi 2. And use the pi 2 as a server. Enough amp?

fruitoftheloom
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Re: p2 powersupply specs?

Thu Feb 05, 2015 5:07 pm

fjr wrote:DougieLawson, I did not intend to send a personal message to anyone. If I did then I apologize.

Maybe someone can explain how my post at the same time could get posted on the forum, because how else could klricks read the post and answer?

Thank you for your answer.
I should have described the hardware setup more precisely. There are power supplies called hdd power supplies. They are 2amp and the voltage output is 12v 5v molex.
That should be enough for pi2 and keyboard and pc mouse and a camera.

A 2tb sata hard drive is 0.5amp? I would like to take a hdd power supply, connect a molex splitter to the power supplier. A molex splitter that splits into a power sata connector and a micro usb connector. Then connect the pi 2 and the hdd to the hdd power supply. And use a sata to usb adapter to connect the hdd to the pi 2. And use the pi 2 as a server. Enough amp?
This applies to the A+/B+ as well as the RPi2, recommended is a quality 2A PSU

https://projects.drogon.net/testing-set ... berry-pi-b
adieu

My other Computer is an Asus CS10 ChromeBit
https://www.asus.com/uk/Mini-PCs/Chromebit-CS10

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DougieLawson
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Re: p2 powersupply specs?

Thu Feb 05, 2015 6:11 pm

fjr wrote:DougieLawson, I did not intend to send a personal message to anyone. If I did then I apologize.
You're reading my standard forum signature line, I prefer folks to ask their technical questions in public where a) everyone gets to see the answer and b) the stuff I write gets peer reviewed by other experts. I may have the second highest posting count on here (and that was generating lots of private messages) but I still make stupid mistakes and still write posts with idiotic speeling errurs.

So apology accepted, but it wasn't needed.
Note: Having anything remotely humorous in your signature is completely banned on this forum.

Any DMs sent on Twitter will be answered next month.

This is a hippy & doctor free zone.

klricks
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Joined: Sat Jan 12, 2013 3:01 am
Location: Grants Pass, OR, USA
Contact: Website

Re: p2 powersupply specs?

Thu Feb 05, 2015 6:17 pm

klricks wrote:
fjr wrote:What are recommended powersupply requirements for pi 2?

If the pi 2 is a server with no usb hard drive?

If the pi 2 is a server with a 2tb usb hard drive?

If the pi 2 used with peripherals, pc mouse, keyboard, etc and no usb hard drive?

If the pi 2 is used with peripherals, pc mouse ... and a 2tb usb hard drive?

Thank you.
Not possible for us to answer directly because you did not give the specifications of each device.
Here is how to figure this out for yourself:
The maximum current into the RPi is limited to 2A.
The maximum current to all of the USB ports combined is 1.2A so that leaves 0.8A for the RPi + anything connected to the GPIO's

You need to find the current draw specification of each USB device and add them up. If <= 1.2A then you should be OK as long as your power supply can deliver the power needed and still maintain the 5V +-5% voltage. If > 1.2A then you will have to use a powered HUB.

Note the default USB power output is 600mA. You must change a configuration setting to get the max 1.2A

So as mentioned you can't go wrong with a 2A supply. A smaller supply can be used for the server with no peripherals.
A larger than 2A supply can be used but has no added benefit.
The message in Dougie's post about not sending a PM is part of his signature file and appears in all his posts. The signature can be set up in user control panel preferences and will appear in all posts, past, present and future.

The power supply arrangement appears good.
Unless specified otherwise my response is based on the latest and fully updated Raspbian Stretch w/ Desktop OS.

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piglet
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Re: p2 powersupply specs?

Thu Feb 05, 2015 6:31 pm

I've found that my Pi2 requires a better PSU than my Pi and PiB+ ones. What was fine on those gives a voltage warning on the Pi2 and frozen machines if I do something intensive.

In all cases same peripherals & usb hard drive used.

When I swapped out the "3A" somewhat dubious quality supply for a branded 2A tablet charger all appears well....so far...

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