Raspberry Pi 4 Power Supply (Official) - USB-C 5.1V 15.3W (White) (CE06427)

True there could be “better” power cords but this is the official one and rather use that, all they need to do is remove the pointless pieces of plastic that sticks out around the charger and the problem is solved.

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Oliver is exactly right, cutting and modifying supplies certainly isn’t the way to go and not what I would recommend that on any supply. That being said, if airflow requirements are an issue the RPi Foundation may be able to redesign the case to be better suited to fit in Australian ports if there’s enough request from the customers to change it.

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Yeah but it doesn’t need it, with loads of use heavy and light as a full PC and many other uses the power supply never gets very warm even after it being on for multiple days or heavy use compiling code or playing games.

Here is how it looks now after I modified it and removed those pointless pieces of plastic

Now it’s clean and not a hog when I plug it is not is not dangerous as again it never gets hot or even at best that warm with use.

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Hey Corey,

I know this probably not what you’re looking for but I just use a small extension cable for annoying supplies like these. Totally agree with the peace of mind that running the official supply gives, though!

-James

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I’ve recently done a couple of voice assistant satellites that require two 5V wall warts, one for RasPi and another for the speaker … and a separate 4-way power board for 2 oversize power supplies. Seems overkill for a small project which in total is only drawing a few amps.
I wonder how many projects end like this ? And how much money, electricity and resources are being wasted by having lots of small power adaptors ?

It would be nice to have a power supply that takes only one wall socket and has two or three 5V leads coming from the power supply (and maybe an option with a 12v or 9V line to power motors or servos). This got me looking at USB chargers - but most don’t provide enough power for a RasPi 4, let alone additional boards - and leads me to the likes of “Comsol 90W USB-C & A 3 Port Wall Charger & Cable” ($99 from Officeworks) or “Quick Charger 3.0, USB Plug Chargers, Total 33W” on amazon which claims to deliver 18W Quick Charge on port one, and 5V at 3.1A on ports 2,3 and 4. reviews, however, are mixed.

Looking on the Raspberry Pi forum there are several who vehemently rubbish anything other than the official Raspberry Pi power supplies. Sure the RasPi power supplies may be good quality (we hear every product touted as high quality, so the phrase has long lost meaning), but it would be nice to have another option or two which are more suited to projects than just a single RasPi.

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Hi Donald,

I can certainly relate to projects that seem to have multiple power supplies each taking up space where you wish you could just have one bigger one that does everything.
The catch with Raspberry Pi power supplies is that the Raspberry Pi boards are officially documented as 5.1V devices.
Many Pi boards do get used with 5V power supplies and work without issue, but we’ve had numerous reports of Pi boards displaying low voltage warnings when combined with USB peripherals and tripping the Pi’s low voltage alert mechanism. This is the reason we recommend use with the official power supplies as it’s one less part to troubleshoot with a supply that is guaranteed and warrantied to work.

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Hi Trent

You are kidding right ??? 5.1V or 5.0V. If RPis are that critical I would not bother reading about them let alone pass over $$$ to purchase. You would probably find that some el cheapo DMMs would be worse than that especially if they have a few years on them. I wonder how many of these “wall warts”, as the Americans call them, have been discarded because the meter says they are out of tolerance.I think mostly it would be the better quality (and more expensive) instruments that you would expect to retain accuracy over several years. Indeed if you are doing “traceable” type work it is usually a requirement to have your instrument’s’ calibration checked annually.

I have dealt with this sort of requirement all my electronic working life and have often thought that when an instrument is calibration checked you could probably assume the last dozen or so and the next dozen or so measurements are OK. Outside of that who knows. I have seen the requirement with production where things like wire wrap and crimp tools are tested before the start and about half way through every day. That could be thought of as being overly fussy but the customer requires it and is paying for it so us mere mortals cannot argue can we??
Cheers Bob

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Off on a different tangent … I note that Core currently have 3 prices for Official Raspberry Pi power supplies:

My understanding is that the colour of the power supply makes no difference; and that it is OK (even desirable) for a power supply to have more amps available than the connected device’s maximum requirement. The Pi 3 also requires 5.1V, so could use the RasPi 4 power supply - except that it does have a different power connector.

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Hi Donald,

The next project in the barrel for me has this exact issue although it requires a bit more power. The best value supply that I came across was this 12V one: 12V DC 5A Fixed 2.1mm Tip Switching Power Supply Australia
Then to get lower voltages I use some step down regulators from Pololu to power the Pi’s. An SMD USB socket for a cable to plug into and voila a power supply for a few different things at varying voltages.

Re the different prices on power supplies, colour wont make a difference, I’d say its supply and demand. If you have some micro USB PSU’s around you can use this to change the connector: https://core-electronics.com.au/usb-micro-b-to-usb-c-adapter-black.html
I belive the extra 0.1V is to make sure when the Pi draws more current the voltage doesnt droop low enough to trip those voltage warnings

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Some time ago I bought a Pi 3B+ and connected a 5.0V supply with more than enough capacity to power the Pi. Upon power up a small message appeared on the GUI saying there was a power supply problem. (cannot remember the msg) The Pi worked fine and I ignored it as I explored the Pi capability.

When I got around to checking why, I discovered the small difference in voltage (5.0V to 5.1V) was the problem. I bought the official Pi plug pack and the message no longer appeared. I used a variable supply of 5.1V and the message no longer appeared.

I don’t know if this is a deliberate design feature to make people buy the official plug pack or a hangover from the original hardware.

The Raspberry Pi Foundation was able to procure the original processor chips at a discounted price, making development of the Pi possible. The original processor was essentially a graphics chip with an embedded RISC processor.

I found all of this information in the Raspberry Pi Forum pages, or it used to be there.
The history of the Pi is quite interesting.

Regards
Jim

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Hi Donald,

Every now and then we have a customer that absolutely must have a power supply in a particular colour for their application, so we started listing the separate colours as separate products on our site after so many requests. Since we purchase them for different prices that is reflected in the final price on the website.
I always just go for the cheaper one, but if you want to be selective about the colour, now you can!

The Pi 4 power supply and Pi 3+ power supply are not rated to the same power output as the Pi 3 boards and Pi 4 boards have different current requirements (due to the faster processors).
The power requirements for each generation of Pi board are available here:

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Hi Bob,

I know it seems ridiculous to think that 0.1 volts would make a difference in this application, for the vast majority of cases 5 volts is sufficient for the board to perform correctly but as @James46717 has documented you will get a rather annoying error message if the Pi notices the lower voltage supply.

My suspicion is that this was done to encourage people to use the official power supply that has some extra current delivery headroom knowing that it would be used in schools and with beginners unfamiliar with power ratings. It’s all well and good to know the Pi’s power requirements but when the end-user will inevitably connect a USB hub and a large number of USB peripherals that also need power via the Pi’s power supply the official power supplies are designed with allowance for that.
The documentation does list an assumed amount of extra USB peripherals are connected:

Interestingly they also show that the low-voltage warning is designed to be triggered at 4.63V (+/- 5%).

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Hi @Donald23173

I note that Core currently have 3 prices for Official Raspberry Pi power supplies

Product origin and purchasing volume are going to have an effect on price. I can confirm that both factors are valid for the parts you linked!

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Ran a test on my Pi 3B+, today.
Keyboard, Mouse, HDMI & Ethernet.

Official Pi Plug Pack, measured 5.22V. All ok.
Plug Pack rated at 5V 2.1A, measured 4.79V. Icon triggered.
So it triggers slightly higher than the 4.63V +/- 5%.

Agree with it being because of school situation and beginners.
I think the Official Plug Pack is a better switch mode than my ordinary plug pack.

Cheers
Jim

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Hi Jim,

Good to have some real-world testing to check the theory!
We do find the failure rate of the official power supplies to very low, nothing is perfect after all, but for power supplies they seem to be exceptionally robust.

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Hi Guys

That is one particular unit. The “real world” could be a bit different with other devices.

4.79V is within 5% of 4.63V so it is within quoted figures. 4.63V plus 5% is 4.86V.

What I am getting at is the difference between 5.1V and 5V should not be a concern. As I stated above some of this could well be meter error. I believe a piece of kit such as RPi or Arduino should be reliable over a spread of voltage as much as 10%. that is +/- 5% or +3% to -7% or something of that order. The manufacturer may publish something like this I haven’t had a close look to be sure. I have not had any problems with this sort of thing myself as I tend to overestimate the loads anyway. As for actual points where a device becomes unstable or unusable I doubt that a manufacturer could publish figures or would want to as each individual circumstance would be different.

I don’t think some contributors pay enough attention to the power supply in use regarding current supply capabilities before they start. I have seen instances where a contributor has measured V at the power supply and measured something less at the device. Advice has been to increase V at power supply to compensate for the loss. I think this is quite wrong and one should find out where and why the V is dropping and do something about that. Granted there are some cases I have seen where the voltage at the load is critical and when supplied from a regulated supply the voltage sensing is actually done at the LOAD to compensate for any drop in the wiring, but I don’t think this situation is applicable to this forum topics.

Personally I tend to over do this a bit. I am currently mucking about with some XMAS lights and so far have 2 strings of 150 Neopixels with an Arduino Pro Mini as the clever bit. Brightness currently at 100 (out of 255) and max current so far 2.5A. To power this I purchased a MeanWell supply of 5V @ 14A. That just about should cover anything more I need to throw at it. May be an overkill but it is something I should not have to worry too much about. The main worry is inrush current possibly tripping circuit breakers but so far so good. I might have to measure this and if a concern do the switching at the 5V level. Another story later.
Cheers Bob

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Hey Bob,

My understanding of the reason they target 5.1v nominal instead of 5v is to give themselves a little extra voltage to compensate for voltage droop under heavy load, while still being USB compliant.

Actually, I just took a bit of a dive into the USB specs. USB Type C voltage requirements are defined in the USB 2.0 specification.

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Interestingly, there was an ECN (Engineering Change Notice) issued in August 2014 which increased the maximum allowable USB voltage from 5.25V to 5.50V - and they’ve even stated cvompensating for voltage droop as the reason:

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I’d be willing to put money on the 5.1V specification being a direct result of that ECN. The original USB spec was 5.0 ±0.25V, but now that it’s 5.0V (-0.25V +0.50V), it’s equivalent to 5.125V ±0.375V - hence the 5.1V of the official Pi supplies.

Percentage wise, that’s 5.0V +10%, -5% or 5.125V ±7.32%

All this is to say that a 5.0V ± 0.25V supply capable of 3A isn’t strictly USB spec compliant and hasn’t been since 2014 - though if the cable and connectors are low enough impedance it’d work fine.

This post says the voltage input requirement of the on-board supply is 4.00V to 5.50V - which is actually the same as the USB 3.2 spec:

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Ah, but don’t forget to account for the impedance of the connector and traces on the board! If you’re pulling 1A and measuring 4.79V at the supply, as little as 90 milliohms would be enough to trip the Power warning on a 3B+.

FYI, here’s the datasheet for the voltage monitoring chip on the Pi 3 boards:
https://www.mouser.com/datasheet/2/115/APX803-82466.pdf

And here’s the one for the Pi 4s:

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Hi Oliver
All very interesting.
What I was really referring to was the publication or lack publication of the reliable operating voltage range of the devices themselves, RPi, Arduino etc. Or a % referred to a nominal 5V.
Cheers Bob

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Thanks for all the excellent research you have done @Oliver. Provides a good light on what the Raspberry Pi corporation is up against in powering the Pi via a USB connection; considering the requirements of version Pi 4. And has refreshed my memory from a few years ago.

The voltage measurements were made at the 40 pin GPIO connector. The easiest place to get the board voltage.

I think this thread has gone way beyond the original intent.
But hopefully it may help other users of Pi devices understand the need for a quality robust USB power source.

Cheers
Jim

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Great deep dive there Ollie!

And some qualitative feedback after distributing thousands of RPi’s; I can confirm we get our fair share of “undervoltage warnings” that miraculously go away when the official RPi 5.1V Power Supply is used. It’s one of the most common “faults” reported, and no surprise given how often it appears online in other communities.

The overall design (electrically, physically) of the RPI PSU is better suited for power delivery compared to chargers and other 5V options that most people have within arms reach. It will ensure RPi will function fine out of the box, and with as many peripheries as you like, right up to its rated specs without the disappointment of unexpected power issues/warnings.

Such a comprehensive discussion - thanks to everyone for sharing their perspectives!

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