niska wrote: ↑
Tue Mar 05, 2019 10:47 pm
Thanks for the reply.
I have a Raspberry Pi 3 Model B+. If I use the official power supply 5V 2.5A, would it work with the Seagate Expansion Portable Drive?
(I'm not sure about the details of the current it can draw. The specs can be found at https://www.seagate.com/www-content/dat ... ble-gb.pdf
That's the problem. Unless you know the maximum current requirement for the drive, no one can tell you if it will work the way you want. With a 2.4A PSU, the Pi will be able to supply a total of 1.2A to the 4 USB ports. If the drive needs more than that...it won't work. If its peak current is less than that, it *might* work, depending on what else is drawing power for a USB port.
Edit 1: I've also read that it is possible to find inofficial power supplies for RPi with 3A instead of 2.5A. Would this be a better choice for me?
That increases the chances that you will still have 5v when the Pi is at full load/max USB draw, but it won't add any available power. The Pi has a current limiting polyfuse and simply can't draw more than the rated current. This is a safety feature.
Edit 2: According to this thread
the "operating power as .7 watt idle and 5.3 watt writing large media files"
5.3W would be 1.06A, which is perilously close to the 1.2A maximum available. It also doesn't specify the max current draw when the drive is spinning up at start. This leads me to strongly suspect that the answer is that you can't run that drive directly from a Pi. Use a poweredd hub instead.