uilfut
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pi3b+ needs a beefier power supply than the pi3b

Fri Mar 16, 2018 1:04 am

This was mentioned in the launch video, but struggling with current 2A random adapters which have always worked for me with pis in the past.

Official raspberry pi adapter is a lot of dollars shipped to Canada. On the lookout for something local... any ideas? 2.5A seems rarer than 2A.

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Imperf3kt
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 1:07 am

It probably doesn't need it...
Have you made sure you are using the absolute latest Raspbian release?
Alternatively (read: in addition), there is always the reasonably priced official power supply.
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W. H. Heydt
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 1:25 am

Imperf3kt wrote:
Fri Mar 16, 2018 1:07 am
Alternatively (read: in addition), there is always the reasonably priced official power supply.
Cost plus shipping on that is what he's complaining about. I'm not sure what type of plugs Canada uses, but there is a less expensive version of the PSU with a fixed, US plug instead of the replaceable plugs on the RPF PSU.

uilfut
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 1:34 am

Imperf3kt wrote:
Fri Mar 16, 2018 1:07 am
It probably doesn't need it...
Have you made sure you are using the absolute latest Raspbian release?
Yeah downloaded from this website, it has worked intermittently. Will keep trying!

uilfut
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 1:35 am

W. H. Heydt wrote:
Fri Mar 16, 2018 1:25 am
Imperf3kt wrote:
Fri Mar 16, 2018 1:07 am
Alternatively (read: in addition), there is always the reasonably priced official power supply.
Cost plus shipping on that is what he's complaining about. I'm not sure what type of plugs Canada uses, but there is a less expensive version of the PSU with a fixed, US plug instead of the replaceable plugs on the RPF PSU.
Yeah I looked it up and they wanted extra $15 CAD to ship the white looking one with US / EU (it looked like) interchangeable plugs. I'll keep looking.

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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 2:48 am

uilfut wrote:
Fri Mar 16, 2018 1:35 am
W. H. Heydt wrote:
Fri Mar 16, 2018 1:25 am
Imperf3kt wrote:
Fri Mar 16, 2018 1:07 am
Alternatively (read: in addition), there is always the reasonably priced official power supply.
Cost plus shipping on that is what he's complaining about. I'm not sure what type of plugs Canada uses, but there is a less expensive version of the PSU with a fixed, US plug instead of the replaceable plugs on the RPF PSU.
Yeah I looked it up and they wanted extra $15 CAD to ship the white looking one with US / EU (it looked like) interchangeable plugs. I'll keep looking.
I can't speak to the shipping to Canada (I ordered a Pi3B+ from Newark Elec. and the shipping was US$6), but they have the "universal" RPF PSU for US$9 here http://www.newark.com/stontronics/t5875 ... dp/77Y6535 and Allied has one with a US-type plug for US$7.50, here: https://www.alliedelec.com/raspberry-pi ... /70947269/ (Allied also has the "universal" version for $9, in both white and black versions).

Edit to add... CanaKit, which is so far as I know, based in BC, has the RPF PSU for CDN$12.95 (=US$9.91). (At least, I assume they price in CDN$.) The one time I ordered from them I found their shipping charges to be kind of high, but it might be more reasonable in-country. You might check to see of RS or Farnell have branches/subsidiaries in Canada.

uilfut
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 3:08 am

Thanks WHH. CanaKit is $14 shipping alone within Canada. Post here is crazy! I'm gonna try High St.

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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 4:50 am

uilfut wrote:
Fri Mar 16, 2018 3:08 am
Thanks WHH. CanaKit is $14 shipping alone within Canada. Post here is crazy! I'm gonna try High St.
I'm inclined to agree with your assessment of Canadian shipping charges. I can get things like Pi0 series and other small items shipped from the UK to California for around US$5.

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PeterO
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 7:33 am

From the people that know ...
Note that Raspberry Pi 3B+ does consume substantially more power than its predecessor. We strongly encourage you to use a high-quality 2.5A power supply, such as the official Raspberry Pi Universal Power Supply.
Their emphasis, not mine.
https://www.raspberrypi.org/blog/raspbe ... le-now-35/

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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 9:32 am

There are two things to consider if you are using a PSU with a separate USB cable. The PSU itself, and the micro-USB cable connection the power to the Pi. Most standard micro-USB cables aren't designed to deliver much more than 500mA (0.5A). To power the Pi3B and especially the new 3B+ you'll want micro-USB cables with fatter power wires. Look for cables with 24 AWG power wires at a minimum, and preferably larger than that (note that a lower AWG number means fatter wires). Also, shorter cables have less resistance, so keep your power connection as short as practical.

See here for a post I made awhile back about some of the best micro-USB cables I have used.
viewtopic.php?f=63&t=165393
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 9:42 am

Imperf3kt wrote:
Fri Mar 16, 2018 1:07 am
It probably doesn't need it...
Have you made sure you are using the absolute latest Raspbian release?
Alternatively (read: in addition), there is always the reasonably priced official power supply.
Wrong!
I did some testing with my early support RPi3B+ and RPF folks. I have a phone charger that gets it booted but some hours later it just dies for no apparent reason.

The official power supply (or one that's better than a steady 2.5A) is a requirement.
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 9:43 am

HawaiianPi wrote:
Fri Mar 16, 2018 9:32 am
To power the Pi3B and especially the new 3B+ you'll want micro-USB cables with fatter power wires. Look for cables with 24 AWG power wires at a minimum, and preferably larger than that (note that a lower AWG number means fatter wires).
The official PSU has a 1.5m integrated cable that is 18AWG thick. I don't know about the 3B+ (mine has not arrived yet), but the official PSU has in the past been guaranteed to work well (and it is cheap!).

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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 9:50 am

Something else to consider about cables.

According to the USB specification, power supplies with sockets are required to provide 5V within spec at the socket. However power supplies with fixed cables are required to provide 5V within spec at the end of the cable.
Therefore a fixed-cable power supply has already taken into account the voltage drop of the cable. But with a plug-in cable you are adding an unknown voltage drop.

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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 9:53 am

rurwin wrote:
Fri Mar 16, 2018 9:50 am
Something else to consider about cables.

According to the USB specification, power supplies with sockets are required to provide 5V within spec at the socket. However power supplies with fixed cables are required to provide 5V within spec at the end of the cable.
Therefore a fixed-cable power supply has already taken into account the voltage drop of the cable. But with a plug-in cable you are adding an unknown voltage drop.
A good point.
I guess though that a thicker cable still helps in that the end voltage should be more stable.

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HawaiianPi
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 11:05 am

jahboater wrote:
Fri Mar 16, 2018 9:53 am
A good point.
I guess though that a thicker cable still helps in that the end voltage should be more stable.
Yup, the problem is many micro-USB cables have unknown specs.

Some will have markings on them similar to this:
USB_wire_gauge.jpg
USB_wire_gauge.jpg (11.1 KiB) Viewed 2443 times
The outlined number is the power wire gauge (24 AWG in this case).

I have micro-USB cables with 23, 21, 20 and even 19 AWG power wires, which all work great with my Pi3B computers. I generally use cables with a length of 1 meter or less (the Pi3B on my desk is powered by a 1.5 ft cable with 23 AWG OFC power wires).

Cables included with (or designed for charging) smartphones and tablets are usually engineered for lower resistance and higher current, so if you have power problems, your phone or tablet micro-USB charging cable might be a good option to try.

Another issue is that phone/tablet charging does not require precise voltage regulation, so some charger type power supplies won't maintain a stable 5V under load. I have tested "5V/2.4A" chargers that dipped well below 5V at only a 1A load. This makes phone chargers somewhat of a crapshoot as a Pi PSU. Some will work fine while others will not, regardless of specs.

I have a 3B+ on the way and I'm confident my phone charger will work, but I have tested it under 2A+ loads so I know what can do, and I have several very high quality micro-USB cables to choose from. For others who don't want to worry about cable specs or PSU load testing, the simple solution is to get the official RPF Pi3 PSU. It's rated for 5.1V at 2.5A and has nice, fat 18 AWG power wires.
Last edited by HawaiianPi on Sat May 25, 2019 5:59 pm, edited 1 time in total.
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 2:38 pm

PeterO wrote:
Fri Mar 16, 2018 7:33 am
From the people that know ...
Note that Raspberry Pi 3B+ does consume substantially more power than its predecessor. We strongly encourage you to use a high-quality 2.5A power supply, such as the official Raspberry Pi Universal Power Supply.
Their emphasis, not mine.
https://www.raspberrypi.org/blog/raspbe ... le-now-35/

PeterO
Yes indeed. Just trying to flag again. This *needs* the official (or equivalent) power supply! Buy one with your new Pi3b+.

Now painful for me to spend $30 delivered for one :(

A PoE hat and adapter might be close in cost..!

I wonder if a hypothetical Pi4 will require a new power supply over and above this, assuming speed is proportional to energy requirement.

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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 2:58 pm

uilfut wrote:
Fri Mar 16, 2018 2:38 pm
I wonder if a hypothetical Pi4 will require a new power supply over and above this, assuming speed is proportional to energy requirement.
My crystal ball, being made of glass (an amorphous material) is kind of fuzzy. Dr. Upton did muse in an interview about going over to a USB-C power connector, but I wouldn't read too much into that. It is rather likely that the Pi4B when it arrives will use a 28nm SoC, rather than the current 40nm process. That should reduce power requirements for the same processor speed. Taken all together, I think it's anybody's guess what the power requirements for the Pi4B will be. If it does go up (or, at least, not go down from where the Pi3B+ is), I would look for a 3A PSU with a USB-C connector, as that would otherwise go well over the specified limit for micro USB.

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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 3:06 pm

Is there any value in speculating. We've had the new Raspberry this week. It's going to be "some time later" when any Raspberry Pi version next processor emerges from its cocoon. Trying to guess when "some time later" will be is an exercise in futility.
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 3:15 pm

Is there any value in trying to stifle speculation?
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 3:21 pm

n67 wrote:
Fri Mar 16, 2018 3:15 pm
Is there any value in trying to stifle speculation?
Yeah and from someone who said he had an "early support" board. They don't like the debate because they can't participate. If Pi4 needs a 2.7A power supply and I have to pay another $30 I'll... stamp my feet.

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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 3:24 pm

uilfut wrote:
Fri Mar 16, 2018 3:21 pm
n67 wrote:
Fri Mar 16, 2018 3:15 pm
Is there any value in trying to stifle speculation?
Yeah and from someone who said he had an "early support" board. They don't like the debate because they can't participate. If Pi4 needs a 2.7A power supply and I have to pay another $30 I'll... stamp my feet.
Are you trying to emulate the troll you've quoted?

Discussing wish lists and pink pony features for some future Raspberry is a brain-dead activity. Discuss the problems you've got with the current generally available hardware, it will have a better outcome.
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 3:34 pm

OK that kinda escalated. Not sure you should call the other person a troll.

The power requirements of the current board make the power supply options much more limited.

This was pointed out at launch.

I still got caught out. My bad.

I was just remarking that if this trend continues, will we have to purchase another new power supply for the next board too, given that we're at the limit of the official power supply apparently.

I'm not trying to annoy anyone who works for raspberry pi. Just a thought that passed my mind.

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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 3:36 pm

uilfut wrote:
Fri Mar 16, 2018 3:34 pm
OK that kinda escalated. Not sure you should call the other person a troll.
Why not? n67 IS a troll and the moderators know it.

I don't work for anyone other than myself. My limited company take sub-contracts from a Mainframe Specialist in Bromsgrove.
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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 3:39 pm

W. H. Heydt wrote:
Fri Mar 16, 2018 2:58 pm
uilfut wrote:
Fri Mar 16, 2018 2:38 pm
I wonder if a hypothetical Pi4 will require a new power supply over and above this, assuming speed is proportional to energy requirement.
My crystal ball, being made of glass (an amorphous material) is kind of fuzzy. Dr. Upton did muse in an interview about going over to a USB-C power connector, but I wouldn't read too much into that. It is rather likely that the Pi4B when it arrives will use a 28nm SoC, rather than the current 40nm process. That should reduce power requirements for the same processor speed. Taken all together, I think it's anybody's guess what the power requirements for the Pi4B will be. If it does go up (or, at least, not go down from where the Pi3B+ is), I would look for a 3A PSU with a USB-C connector, as that would otherwise go well over the specified limit for micro USB.
Something like this?

https://www.amazon.com/Charger-iClever- ... 20WYATR3HH

I get scared when it says "smart" - I'm assuming the pi just needs consistent.

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Re: pi3b+ needs better power supply

Fri Mar 16, 2018 5:16 pm

DougieLawson wrote:
Fri Mar 16, 2018 3:36 pm
uilfut wrote:
Fri Mar 16, 2018 3:34 pm
OK that kinda escalated. Not sure you should call the other person a troll.
Why not? n67 IS a troll and the moderators know it.

I don't work for anyone other than myself. My limited company take sub-contracts from a Mainframe Specialist in Bromsgrove.
Yeah you might have a point.

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