Raspberry Pi Forums

I just bought a Raspberry Pi 3 and I'm trying to figure out how to set it up. Its just the RPi, not the starter kit (which I'm now kindof regretting lol).

My question is, is it possible to power the RPi from a mac laptop with a usb adapter and ethernet cable?

When I plug everything in, there is no notification that anything is actually working, or that the RPi is booting.

Below are the steps I've taken:
1. Used SD Formatter to format SD Card
2. Unmounted the card
3. Transferred Jessie-Lite onto the card
4. Put the card into the RPi
5. Plugged the cable from my laptop into the RPi.

But nothing happens. So I'm wondering if there could be some issues with not enough power being transferred, or if this setup just doesn't work. Note: my laptop is plugged in.

I'm a little bummed that I bought the hardware and then I can't figure out how to make it work. So any guidance would be appreciated!

The Pi3 cannot be powered through the Ethernet port.

The normal power input is through the micro-USB port, and the recommended power supply is 5V/2.5A.

It's also possible to power it through the GPIO pins, but I believe that bypasses the polyfuse protection.

A full power USB 3 port will run a Pi 3. They put out a couple of amps. They are sometimes called charger ports. Some Apple USB ports have weird non standard power. You would have to look up the specs for that model Apple device.

When you have more than one USB device plugged in, the maximum power for all the ports is often less than the maximum power per port multiplied by the number of ports. Unplug all other USB devices.

A Pi 3 with something plugged into a USB port can easily require the full 2.5 amps, slightly more than a USB 3 port provides. I can run a Pi 3 from USB 3 with a keyboard dongle plugged in but not with a 2.5" disk plugged in. The 2.5 amp power will run the Pi with the 2.5" disk plugged in.

slow-guy wrote:I just bought a Raspberry Pi 3 and I'm trying to figure out how to set it up. Its just the RPi, not the starter kit (which I'm now kindof regretting lol).

My question is, is it possible to power the RPi from a mac laptop with a usb adapter and ethernet cable?

When I plug everything in, there is no notification that anything is actually working, or that the RPi is booting.

Below are the steps I've taken:
1. Used SD Formatter to format SD Card
2. Unmounted the card
3. Transferred Jessie-Lite onto the card
4. Put the card into the RPi
5. Plugged the cable from my laptop into the RPi.

But nothing happens. So I'm wondering if there could be some issues with not enough power being transferred, or if this setup just doesn't work. Note: my laptop is plugged in.

I'm a little bummed that I bought the hardware and then I can't figure out how to make it work. So any guidance would be appreciated!

You need a separate PSU for the Raspberry Pi, there is no other way with your setup:

http://uk.rs-online.com/web/p/plug-in-p ... ly/9098126

You haven't mentioned how you expect to be notified that anything is happening.

peterlite wrote:A full power USB 3 port will run a Pi 3. They put out a couple of amps...

Actually, the USB 3.0 standard is 900mA (0.9A).

peterlite wrote:They are sometimes called charger ports...

This is something different altogether. Some computers are equipped with charging ports that output more power and have the ability to charge when the system is in standby mode, but that is not standard for every USB 3.0 port.

When a Pi3 is used for common things like surfing the web or media consumption it will typically draw less than 1A, so it could run off of a USB 3.0 port. But as you discovered, as soon as you start adding any real power demands, it won't work. I have used my Pi3 with an external USB powered HDD with a 2A supply, so if USB 3.0 ports truly "put out a couple of amps" it should be enough for one external HDD.

I have even successfully spun up and mounted TWO external USB powered hard drives with my Pi3 powered by a 5.3V/2.4A supply, but I could only use one at a time (trying to RAID them, or copy from one to the other resulted in intermittent drive disconnects).

Turns out that "battery charging" spec is 1.5 amps but some devices advertise 2.2 amps. My main USB 3 hub will drive a Pi 3 with USB devices plugged in, about 1.2 or 1.3 amp, but not with the addition of a disk, 0.8 amp. I guess my USB 3 hub is pumping out 1.5 amps on several or all ports. The overall power supply is 4 amps.