chris_c
Posts: 156
Joined: Sun May 06, 2012 10:23 am

power requirements

Tue Sep 22, 2015 1:23 pm

What's the maximum draw of the LCD + interface board ?

by the time you have pi2 @1ghz, keyboard, mouse, etc all plugged it I'm thinking to allow any kind of wiggle room probably a 4A power supply would be likely needed (as estimate only) I'm certainly seeing warnings with a 2A supply

While I could use a powered usb hub to take the pressure off I'd rather keep it all more portable and just have the one supply

Any ideas or thoughts on the best way to amply(sorry!) power everything

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1421
Joined: Sat Sep 10, 2011 11:43 am

Re: power requirements

Tue Sep 22, 2015 1:31 pm

We would suggest you buy the Raspberry Pi official power supply, this is a 2.5A power supply with large gauge wiring to reduce the voltage drop on the cable.

This should be ample for Pi 2 + USB peripherals and display

Gordon
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Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

W. H. Heydt
Posts: 10618
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: power requirements

Tue Sep 22, 2015 3:44 pm

chris_c wrote:What's the maximum draw of the LCD + interface board ?

by the time you have pi2 @1ghz, keyboard, mouse, etc all plugged it I'm thinking to allow any kind of wiggle room probably a 4A power supply would be likely needed (as estimate only) I'm certainly seeing warnings with a 2A supply

While I could use a powered usb hub to take the pressure off I'd rather keep it all more portable and just have the one supply

Any ideas or thoughts on the best way to amply(sorry!) power everything
The polyfuse on the A+, B+ and Pi2B is going to limit the board to 1.8A. Someone posted that the display+controller draws 0.43A, so anything over about 2.2A isn't going to be used no matter what you do.

fruitoftheloom
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Location: Delightful Dorset

Re: power requirements

Tue Sep 22, 2015 4:07 pm

gsh wrote:We would suggest you buy the Raspberry Pi official power supply, this is a 2.5A power supply with large gauge wiring to reduce the voltage drop on the cable.

This should be ample for Pi 2 + USB peripherals and display

Gordon
https://www.raspberrypi.org/products/un ... wer-supply
adieu

Asus CS10 Chromebit / HP Envy 4500 Wireless Printer / Raspberry Pi Model 2B v1.1 / RealVNC Software...

chris_c
Posts: 156
Joined: Sun May 06, 2012 10:23 am

Re: power requirements

Tue Sep 22, 2015 5:42 pm

is it possible to power the interface board separately to the pi ?

while the fuse on the PI may limit whats drawn from the pi, the powers connected to the interface, so the .4+A isn't going through the poly fuse?

I'm looking at something like this to drive everything (including small usb powered hub) but would ideally like the all stuff getting their own power rather than the lcd interface board powering the PI and then the PI powering all the USB stuff - that way hopefully I can nail it all down into some kind of (carry?) case powered with just one plug

W. H. Heydt
Posts: 10618
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: power requirements

Tue Sep 22, 2015 8:09 pm

chris_c wrote:is it possible to power the interface board separately to the pi ?

while the fuse on the PI may limit whats drawn from the pi, the powers connected to the interface, so the .4+A isn't going through the poly fuse?

I'm looking at something like this to drive everything (including small usb powered hub) but would ideally like the all stuff getting their own power rather than the lcd interface board powering the PI and then the PI powering all the USB stuff - that way hopefully I can nail it all down into some kind of (carry?) case powered with just one plug
The controller and Pi can be powered independently. While I haven't actually looked, I would be *very* surprised if the controller board lacks overvolt/overcurrent protection. It would be very poor design to neglect that sort of thing, and the RPF is noted for good design...even if a bit *too* protective at times (remember the 140mA polyfuses for the USB ports on the original version of the Model B?).

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