hmnit
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Using the Raspberry pi 4 charger

Sat Jul 20, 2019 10:58 pm

Hi I just bought the raspberry pi 4 but it says that I have to use a 5v 3a charger. I only have 5v 2.4a power bank(my phone charger is 5v 2a). Can I use this 5v 2.4a? I'm just worried that it might break the raspberry pi or is it just fine? If it has any negative effects on the pi I will get a new charger. Thank you so much for your help.

ps. I also live in a 220v country does this difference matter?(from a 110v country)

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rpdom
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Re: Using the Raspberry pi 4 charger

Sun Jul 21, 2019 7:02 am

You can try. It won't break the Pi, but it may cause problems if the power is insufficient. It is possible that it could cause corruption or damage of the micro SD card if the power is too low.

Please note that the Pi requires a Power Supply, not a Charger (there is no battery to charge) and the standards for a Power Supply are a bit stricter than for a Charger.

220V shouldn't be an issue as long as the power supply is designed to accept that input. We have (approximately) 240V here in the UK.

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B.Goode
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Re: Using the Raspberry pi 4 charger

Sun Jul 21, 2019 7:20 am

hmnit wrote:
Sat Jul 20, 2019 10:58 pm
Hi I just bought the raspberry pi 4 but it says that I have to use a 5v 3a charger. I only have 5v 2.4a power bank(my phone charger is 5v 2a). Can I use this 5v 2.4a? I'm just worried that it might break the raspberry pi or is it just fine? If it has any negative effects on the pi I will get a new charger. Thank you so much for your help.

ps. I also live in a 220v country does this difference matter?(from a 110v country)

it says that I have to use a 5v 3a charger.
Can you provide a reference to this advice? Presumably it is not documentation issued by Raspberry Pi themselves.

A Raspberry Pi board has no chargeable components. It requires a Power Supply not a charger. The requirements for the power regulation of a device designed as a charger don't necessarily meet the needs of a Power Supply for an RPi board.

Anything else may work, but might cause you frustration by not working reliably. And if it exceeds the safe working voltage of your RPi board fatal damage may occur.


Any device (including a charger or power supply) to be powered from an AC 'mains' supply must be appropriately rated for the voltage of that supply. Some, but not all, devices are 'universal' and safe for use on both common mains voltages. Others might fail dangerously.

(Edit: to acknowledge that this replicates/overlaps with some of what has been said as I was typing this... )

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Re: Using the Raspberry pi 4 charger

Sun Jul 21, 2019 7:28 am

hmnit wrote:
Sat Jul 20, 2019 10:58 pm
Hi I just bought the raspberry pi 4 but it says that I have to use a 5v 3a charger.
Oh boy here we go again.... bring out the popcorns and drinks!

Try if you must.... regret if you will
might seem workable to you, but still
with the recommended PSU, a peace of mind it will instill.
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"

hmnit
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Re: Using the Raspberry pi 4 charger

Mon Jul 22, 2019 3:07 am

Can you provide a reference to this advice? Presumably it is not documentation issued by Raspberry Pi themselves.
it is on the first page of the raspberry pi 4 documentation.

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HawaiianPi
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Re: Using the Raspberry pi 4 charger

Mon Jul 22, 2019 3:29 am

hmnit wrote:
Mon Jul 22, 2019 3:07 am
it is on the first page of the raspberry pi 4 documentation.
I doubt it says "charger" anywhere in the official documentation, because Raspberry Pi computers do not have batteries or anything else that needs to be charged. What you want is a 5V/3A POWER SUPPLY.

A charger may work, but may have poor voltage regulation and not work reliably under heavy loads. Typically this won't harm the Raspberry Pi, but it may corrupt data on the SD card, and in rare cases it may cause the SD card to fail (read-only).

Every time a new, more powerful Raspberry Pi computer is released we go through this. Someone always wants to use a phone charger instead of purchasing the (very affordable) official power supply. It's up to you if you want to do this. It may work fine, and in the event it doesn't, it probably won't do any harm (other than data corruption). Just be aware of the slim possibility of your SD card going read-only and requiring replacement.

If your charger is a higher powered unit for a laptop, then it likely won't work at all, since the Pi4 misidentifies itself to e-marked/PD type chargers (which are typically laptop chargers). If it has a removable USB cable you might be able to get it working with a non e-marked/PD cable between the charger and the Pi4 (again, this is entirely up to you, and at your own risk).
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HawaiianPi
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Re: Using the Raspberry pi 4 charger

Mon Jul 22, 2019 4:07 am

Just to be clear, the Raspberry Pi 4B does not "require" a 5V/3A power supply, but that is what is recommended for best performance.

Of the 3A in that recommendation, 1.2A is to power devices connected to the USB ports. Subtract 1.2A from 3A and that leaves 1.8A for the system board itself. So in theory, a headless 4B should be able to run off of a 2A power supply.

My 4B system is currently running off of the 2.5A official power supply that was sold for the Pi 3B/3B+ models (using a USB-C adapter), and it runs fine, even with the OS loading and running from a USB 3.0 SSD. I also have a Logitech Unifying wireless keyboard/mouse dongle and a USB 2.0 flash drive. I'm connected to a 1080p HDMI monitor, analog speakers and 5GHz WiFi.

Your 2A charger might let you use the Pi4 lightly, but you won't have much power reserve and will likely run into problems if you push the system hard (which is not difficult to do, since even streaming youtube is pretty demanding).

2.4A could be enough for typical use, but a power bank is not ideal (it needs to be charged).

My recommendation is to get the official 5.1V/3A USB-C power supply.
https://www.raspberrypi.org/products/ty ... er-supply/
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hmnit
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Re: Using the Raspberry pi 4 charger

Mon Jul 22, 2019 4:18 am

HawaiianPi wrote:
Mon Jul 22, 2019 3:29 am
hmnit wrote:
Mon Jul 22, 2019 3:07 am
it is on the first page of the raspberry pi 4 documentation.
I doubt it says "charger" anywhere in the official documentation, because Raspberry Pi computers do not have batteries or anything else that needs to be charged. What you want is a 5V/3A POWER SUPPLY.

A charger may work, but may have poor voltage regulation and not work reliably under heavy loads. Typically this won't harm the Raspberry Pi, but it may corrupt data on the SD card, and in rare cases it may cause the SD card to fail (read-only).

Every time a new, more powerful Raspberry Pi computer is released we go through this. Someone always wants to use a phone charger instead of purchasing the (very affordable) official power supply. It's up to you if you want to do this. It may work fine, and in the event it doesn't, it probably won't do any harm (other than data corruption). Just be aware of the slim possibility of your SD card going read-only and requiring replacement.

If your charger is a higher powered unit for a laptop, then it likely won't work at all, since the Pi4 misidentifies itself to e-marked/PD type chargers (which are typically laptop chargers). If it has a removable USB cable you might be able to get it working with a non e-marked/PD cable between the charger and the Pi4 (again, this is entirely up to you, and at your own risk).
Sorry, it does say power supply on the documentation. I did not know charger and power supply were totally different. It was my lack of understanding. Thank you though for explaining thoroughly to someone who is new to Raspberry pi.

ps. sorry but I have another question. It would mean a lot if you could help.
I found a usb charging that is 5v 3.1a lying around my house. Now I want to use this and I have a Samsung note 8 phone cable (with some research I found that it supports 2a+ with 24 gauge cable). Do you think this cable will work fine as it supports 2a+?
Thank you

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Imperf3kt
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Re: Using the Raspberry pi 4 charger

Mon Jul 22, 2019 4:38 am

It should work well enough provided you don't stress the system too much ior use power hungry usb devices
Give it a try and keep an eye on the top right corner of your monitor for the low voltage indicator.

Be aware though that the specs published on such devices aren't always completely accurate / the whole picture. Trust them with a grain of salt.
55:55:44:44:4C
52:4C:52:42:41

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davidcoton
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Re: Using the Raspberry pi 4 charger

Mon Jul 22, 2019 6:57 pm

hmnit wrote:
Mon Jul 22, 2019 4:18 am
I found a usb charging that is 5v 3.1a lying around my house. Now I want to use this and I have a Samsung note 8 phone cable (with some research I found that it supports 2a+ with 24 gauge cable). Do you think this cable will work fine as it supports 2a+?
If the "charger" will maintain a minimum of 4V75 at the Pi while supplying 3A, it will be fine. As above, that is a "worst case" requirement and you may not actually need 3A anyway. The cable (24AWG) is a bit thin, the official PSU uses 18AWG (thicker) for a good reason. (The clue is "supports 2A+". The design goal is 3A unless you know the current requirement of your particular setup.)
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Re: Using the Raspberry pi 4 charger

Mon Jul 22, 2019 7:17 pm

hmnit wrote:
Mon Jul 22, 2019 4:18 am
Sorry, it does say power supply on the documentation. I did not know charger and power supply were totally different. It was my lack of understanding. Thank you though for explaining thoroughly to someone who is new to Raspberry pi.
A power supply (PSU) is basically a charger with hair on it's chest. The major difference is that a PSU specifies that the output current can be supplied *and* maintain the specified voltage. A charger may or may not do that. This is because a battery being charged isn't very fussy about input voltage, so long as it is enough above the battery voltage to charge said battery. A Pi, really, really "wants" full voltage (at least 4.75v) *and* whatever current, up to its maximum rating, at the same time. So what it comes down to is that a PSU has much more robust voltage regulation, especially when subject to maximum rated load.

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HawaiianPi
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Re: Using the Raspberry pi 4 charger

Mon Jul 22, 2019 8:18 pm

davidcoton wrote:
Mon Jul 22, 2019 6:57 pm
The cable (24AWG) is a bit thin, the official PSU uses 18AWG (thicker) for a good reason.
USB-C cables have multiple power wires, so 24 AWG might be enough, depending on how many internal power wires the cable in question actually has (3x24 AWG should be fine, but if it only has 1...).

USB C-C cables should have all power wires and be rated for a minimum of 3A. USB A-C cables may or may not utilise all power wires, and may not have a 3A rating (2-2.4 amp is common for USB 2.0 A-C charging cables).
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