Power emonpi by raspberry v3/v4 micro-usb / usb-c

CelsoHenriques · 2020-03-24T01:01:08.640Z

Is it possible to power emonpi by using the micro-usb socket of the raspberry pi 3 or the usb-c rpi 4?
In theory, i think it is but i need confirmation from someone who knows.

I am thinking swaping my emonpi rpi 3 to rpi 4 and with that, using a ssd ( using one has led my emonpi to low power issues). I have a rpi4 power transformer but i can’t find any trusty adaptor usb-c to mini-usb and i am not willing to buy one that could get me fire risk.
So i remenber that rpi has power input socket inside the emonpi.

i have been searching but didn’t find anything related to this.

Will the emonpi default power socket be, in the future, changed for another one, more updated?

Thanks
Celso

glyn.hudson · 2020-03-24T16:08:57.001Z

I’m afraid the emonPi needs to be powered by the USB port on the emonPi PCB, or by wiring 5V directly into the emonPi. The reason for this is that the RasPi 3.3V rail can only safely supply 50mA.

We have tested the emonPi with a RasPi4, it’s possible to sufficiently power the unit using a 22AWG mini USB cable:

Shop | OpenEnergyMonitor

Mini-USB cable 22AWG

Open-source hardware tools for energy monitoring and visualisation

and 2A USB 5V adaptor:

Shop | OpenEnergyMonitor

5V DC USB Power Adapter (UK Plug)

Open-source hardware tools for energy monitoring and visualisation

CelsoHenriques · 2020-03-24T16:22:39.000Z

Well, you are right, just the rpi4 it is possible, but with SSD, no.

And that is my problem. And, at least in Portugal,i didn’t find any reliable mini-usb to usb-c adaptor, to make use of the rpi4 oficial power supply.

Glyn Hudson via Community noreply@community.openenergymonitor.org escreveu no dia terça, 24/03/2020 à(s) 16:14:

glyn.hudson · 2020-03-25T12:10:04.718Z

You could power the RasPi via USB and power the emonPi via a mini USB cable. This would enable an SSD to be powered from the RasPi. Alternatively you could use a powered USB hub.