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Re: What can I use for a power supply?

Posted: Sat Mar 19, 2016 11:35 am
by JanoriaCorven
Sorry for the late reply.

Please see the image URL below:

http://imgur.com/9fYEafI

Re: What can I use for a power supply?

Posted: Sat Mar 19, 2016 4:17 pm
by Burngate
Ok, the dotted horizontal line below solid line means DC. (got it inverted in my last post. Sorry)

According to one site I looked on, it appears to have a USB connector, so it should be 5v, and 2.0A should be enough under most circumstances for a Pi 3B

However, with the possibility of 9.0v coming out of it, I wouldn't trust it!
Maybe a Galaxy S6 would talk to it, and without that happening it won't switch to 9v. But maybe not. For the sake of a few dollars, do you want to risk it?

Re: What can I use for a power supply?

Posted: Sat Mar 19, 2016 10:17 pm
by JanoriaCorven
Good call.... no i wouldnt. Too much risk

Re: What can I use for a power supply?

Posted: Sat Mar 19, 2016 10:22 pm
by SteveDee
JanoriaCorven wrote:...Please see the image...
This is an "adaptive fast charger" so it may over-voltage in order to provide what it considers to be the required charging current. It may attempt to determine battery state by assessing voltage. But as you don't have a battery, it is not clear what this will do, so don't try to use this as a Pi supply.

Re: What can I use for a power supply?

Posted: Tue May 31, 2016 2:49 pm
by sreevisakh
I have a 5.5v 600mA AC adapter, which I am able to use for my rpi, But when I connect my harddisk to one of the usb port it restarts. I tried 5V 3A, USB Hub, rpi itslef is not starting up, If I have to connect my usb harddisk to it what should I be using?

Re: What can I use for a power supply?

Posted: Wed Jun 01, 2016 2:56 am
by SteveDee
sreevisakh wrote:... If I have to connect my usb harddisk to it what should I be using?
If the Pi restarts and then runs normally with the USB drive connected, it shows that the inrush current (the higher initial current) is pulling down the 5.5Volt supply momentarily, just long enough to reset the Pi.
If you can't live with that (i.e. only connect the drive when the Pi is off) then you need a bit more power.

The problem with power supplies that output 5Volts (as distinct from those that provide an over-voltage e.g. 5.2V) is that there are voltage losses due to connectors and connecting cable. So the voltage at the Pi is often less than 5V. You are likely to have problems if it falls much below 4.8V (see my post: http://captainbodgit.blogspot.co.uk/201 ... rrypi.html)

The reason that some power supplies rated at 2 or 3Amps seem to work is not due to the current rating, but because the voltage is 5.2V (or maybe 5.5V) at the power supply and this provides at least 5V on the Pi itself.

I dont know what power rating you need, because I dont know the initial and running current your system is drawing from the supply. However I suspect the Northpada supply will be ok (https://www.amazon.co.uk/gp/customer-re ... B00MTX9GD8).

I hope this helps.

Re: What can I use for a power supply?

Posted: Sat Sep 03, 2016 1:23 pm
by _LLJY
Burngate wrote:Ok, the dotted horizontal line below solid line means DC. (got it inverted in my last post. Sorry)

According to one site I looked on, it appears to have a USB connector, so it should be 5v, and 2.0A should be enough under most circumstances for a Pi 3B

However, with the possibility of 9.0v coming out of it, I wouldn't trust it!
Maybe a Galaxy S6 would talk to it, and without that happening it won't switch to 9v. But maybe not. For the sake of a few dollars, do you want to risk it?
This is a little old but let me clear it up. As an Android dev, I know what QC 2.0 and AFC does. So, to correct what you just said about it being risky, the raspberry pi doesn't have a QC ic or chip to interface with the charger therefore the charger will NOT output 9V. Quick chargers require kernel drivers and a special Ic/chip to work. So in other words, a quickcharger will not damage your rpi as long as it is not rated above 5V as it's lowest state.

Re: What can I use for a power supply?

Posted: Sat Sep 03, 2016 4:29 pm
by Burngate
Thanks for clearing that up.

Re: What can I use for a power supply?

Posted: Sat Sep 03, 2016 5:24 pm
by stderr
_LLJY wrote: the raspberry pi doesn't have a QC ic or chip to interface with the charger therefore the charger will NOT output 9V. Quick chargers require kernel drivers and a special Ic/chip to work. So in other words, a quickcharger will not damage your rpi as long as it is not rated above 5V as it's lowest state.
If the pi did accept higher voltages, then such a charger even going nuts would not damage it, for certain definitions of going nuts. It's pretty clear that there is a very narrow range of power supplies that people can just find laying around that will currently work and that's really too bad.

Re: What can I use for a power supply?

Posted: Tue Jun 12, 2018 10:25 pm
by as1mov48
Why not use a 'reliable' outlet bar and 3 power supplies. there shouldn't be much of a drain on your supply. I've left two running using a outlet bar with 4 x switched outlets for a couple of weeks with no BAD results.
Sounds better than some pricier solutions. You'll get a decent 4 gang extension from Maplin or even eBay but watch eBay's renderings. Preferably good old Maplin.
Hope this helps.
as1mov (retired spark)