po220
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Rasp3B+ with SSD How to power ?

Thu Nov 15, 2018 4:09 pm

Hi,
I am a new raspberry fan and use a P3 B+ board with SSD.

with an old SSD the card starts and then displays an explicit message that the voltage is too low after the end of startup.
with another SSD (Kingston A400) the card starts then works well but from time to time it can block for the same reason.

I have apparently a good quality 2.5A power supply
I read to take power 3A I read to take power 3A but the documentation indicates a 2.5 USB connector https://static.raspberrypi.org/files/pr ... rief.pdf
so 3A it would be too much

what is the best practice for connecting and supply a SSD ?

Thanks

zardoz99
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Re: Rasp3B+ with SSD How to power ?

Thu Nov 15, 2018 6:46 pm

I have a RPI 3b+ that is directly connected to an Orico external USB 3.0 enclosure with a 120GB Kingston A400 in it.

This boots directly off the SSD and I have never had any problems with the power consumption of the SSD, even though it draws it all from the RPI USB socket.

Update : just out of curiosity I inserted a USB power meter in line with the SSD enclosure. Max draw under load was 170mA and quiescent was about 110mA. Voltage at the USB port is 5.07V at full load, giving 0.811W.
Last edited by zardoz99 on Thu Nov 15, 2018 6:57 pm, edited 2 times in total.

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DarkPlatinum
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Re: Rasp3B+ with SSD How to power ?

Thu Nov 15, 2018 6:51 pm

I am using the Official 2.5A 5.1V power supply with a 3B+. I boot a Seagate expansion HDD from the usb port. No power issues with it.
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W. H. Heydt
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Re: Rasp3B+ with SSD How to power ?

Thu Nov 15, 2018 7:24 pm

po220 wrote:
Thu Nov 15, 2018 4:09 pm
I have apparently a good quality 2.5A power supply
I would say apparently not, unless it has a separate USB cable and said cable has very thin wires. Going to 3A won't solve a cable problem and the Pis own circuits will prevent it from drawing over about 2.5A. The only reason anyone would suggest a 3A PSU is to have been assurance that the Pi will actually be able to draw 2.5A.

FYI...I have Pi3Bs running from SSD without issue and a Pi3B+ running from a WD PiDrive, where the HDD is powered by the Pi and there are no issues. When I first started using the PiDrive with a Pi3B, I only had a 2A PSU and it worked fine. So...either your 2.5A PSU or the cable connecting it to the Pi are....suspect.

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HawaiianPi
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Re: Rasp3B+ with SSD How to power ?

Thu Nov 15, 2018 8:39 pm

po220 wrote:
Thu Nov 15, 2018 4:09 pm
I have apparently a good quality 2.5A power supply
Considering that you are here complaining of power problems, I find that statement questionable. How do you know it's a "good quality" power supply? Have you load tested it? Exactly which "good quality" power supply are you using, and does it use a separate micro USB cable or have a built-in cable?

Many so-called "power supplies" for Pi computers are really just re-purposed phone chargers, and phone chargers are lousy power supplies because they often have poor voltage regulation. In addition, most standard micro USB cables aren't designed to deliver much more than 500mA of current without voltage loss. So you not only need a proper power supply with good voltage regulation, you need a power cable with thick, low resistance wires and a high amp rated micro USB plug.

If your power supply requires a separate micro USB cable, try a shorter cable, or a cable designed for charging a phone or tablet. And if that doesn't help, get the official Raspberry Pi Universal Power Supply.

I've run several Pi 3B and 3B+ computers from SSD and hard drives with no power issues using the official Raspberry Pi Universal Power Supply. The official power supply outputs 5.1V at up to 2.5A and has a built-in micro USB power cable with fat 18 AWG power wires.
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po220
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Joined: Thu Nov 15, 2018 3:04 pm

Re: Rasp3B+ with SSD How to power ?

Sun Nov 18, 2018 7:44 pm

Hi

Thank you for your answers.
I did not have other power or shorter USB cable but I modified a USB cable to put 18AWG wire and no problem with it.

An infrared thermography control allowed me to confirm that the power supply does not heat (compared to Raspberry) and the USB connector does not heat too

thanks

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DarkPlatinum
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Re: Rasp3B+ with SSD How to power ?

Sun Nov 18, 2018 7:49 pm

po220 wrote:
Sun Nov 18, 2018 7:44 pm
Hi

Thank you for your answers.
I did not have other power or shorter USB cable but I modified a USB cable to put 18AWG wire and no problem with it.

An infrared thermography control allowed me to confirm that the power supply does not heat (compared to Raspberry) and the USB connector does not heat too

thanks
Well your going to have to buy an official power supply for your SSD to work mate.
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fruitoftheloom
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Re: Rasp3B+ with SSD How to power ?

Sun Nov 18, 2018 7:53 pm

DarkPlatinum wrote:
Sun Nov 18, 2018 7:49 pm
po220 wrote:
Sun Nov 18, 2018 7:44 pm
Hi

Thank you for your answers.
I did not have other power or shorter USB cable but I modified a USB cable to put 18AWG wire and no problem with it.

An infrared thermography control allowed me to confirm that the power supply does not heat (compared to Raspberry) and the USB connector does not heat too

thanks
Well your going to have to buy an official power supply for your SSD to work mate.

LMFTFY

https://www.raspberrypi.org/products/ra ... er-supply/
Thinking outside the box is better than burying your head in the sand...

Rascas
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Re: Rasp3B+ with SSD How to power ?

Mon Nov 19, 2018 12:17 am

You didn't mention the OS version you are trying to boot from USB (SSD, USB pendrive, whatever). Anyway, check /boot/cmdline.txt root part and change it to /dev/sda2, make sure you only have one USB disk connected, otherwise, it may change. Do the same to your /etc/fstab. You can always define by PARTUUID instead of device, but you have to note and change accordingly to your case.
This may be needed if your clonning an already setup OS.

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