Home Assistant OS running Network UPS Tools on a RPI4 with a UPS


Apologies in advance, this is going to be a REALLY stupid question but hopefully someone may know the answer, (any mocking and derision is accepted).

So I wanted to get a standalone UPS for the Raspberry Pi 4 I have running HASSOS. I have settled on this one: https://www.amazon.co.uk/dp/B0828G42KN?psc=1&ref=ppx_yo2ov_dt_b_product_details

I also want to be able to run the Network UPS Tools integration in Home Assistant to monitor the power levels of the UPS in case of a power outage and thus shut down the Raspberry Pi before the UPS runs out of charge.

So my question is, (and here comes the stupidity), in order to run the Raspberry Pi off the UPS and for the Network UPS Tools integration to work in Home Assistant, should the Raspberry Pi be only connected and powered by the USB port on the UPS (yellow circle on screenshot), or should the Raspberry Pi be powered by the outlet (red circle on screenshot below), or should the Raspberry Pi be powered by the outlet AND also be connected by USB as well in order for the Network UPS Tools integration to work?

Apologies if this is a stupid question. I tried searching the internet for answers but perhaps this is too basic a question.



Powered by the power port… data on the USB port.

Hi Nathan,

So should both the power port and USB port be connected?


Yes. The power should drive the Pi.

The data port tells NUT on home assistant when weird stuff happens.

Thanks Nathan. I don’t suppose it matters if the UPS in connected to the Pi via the USB C or USB A port does it?

For the data side no. Shouldn’t but on Pi I always leave the USB 2 (not blue) ports open for various sticks like ZWave zigbee etc. Because those don’t like USB3. Considering the data for your UPS doesn’t care you might throw it into one of those to keep the other ports open for other stuff… Maybe?

I took a look at the user guide for this ups and it appears that the USB ports are for charging only, not for data/monitoring. I cannot determine whether the usb charging ports are “protected” meaning they may not be connected to battery backup, so it’s likely best to power the pi using a mains port.

This model ups does not have a usb port for data / status monitoring, it has an rj45 port which requires a proprietary cable, sold separately, to connect to a computer’s usb-a port. I did not review the NUT docs to ensure this model is on the list of supported devices.

Update: some Amazon customers report the usb charging ports are protected, but they’re labeled 2.4A max and raspberry recommends 3A min for a Pi. Also a few reviewers seem to have received a free rj45 monitoring cable, but most had to buy it separately.

Hi peterxian,

Thanks for your feedback - much appreciated. So do you know of a particular make/model of UPS that you can suggest that would allow me to power the Raspberry Pi running HASSOS and also allow me to use the Network UPS Tools integration to work in Home Assistant to monitor the power levels of the UPS.


It’s interesting because the inventory from the manual shows that the monitoring USB should be included. I wonder if the folks that did not receive the cable, received returned units.

EDIT: Looks like those are older reviews.

The one that you linked to should work as long as the monitoring cable is in the box when you receive it.

Right? But then there’s the part on page 9 of the manual where it says “connect an RJ45/USB cable (not supplied) to connect the Back-UPS to a computer” so hard to know for sure which part of the manual is up-to-date… :face_with_raised_eyebrow:

I took a look at the NUT compatibility list and don’t see the Back-UPS BE* series on the list, however other supported models do have the same RJ45 port, so again there is a chance but no guarantee that it will work. Personally, I would just pick a model that is on the list and has a regular USB monitoring port instead of something proprietary. I’ve been using CyberPower CP* series (from Prime Day sales) and am pretty happy with them.

Edited to add: generally speaking, most of the UPS I’ve seen with USB monitoring ports use a Type-B USB connector, to signify it is a client device, similar to a printer, but not all manufacturers follow this standard either.

Thanks everyone for your comments and feedback. The UPS is due to be delivered tomorrow. I’ll report back then on whether the RJ45/USB cable is included and whether I can get it running with the Network UPS Tools integration in Home Assistant.

According to the Manual, the RJ45 port, which is to be used with a RJ45-to-USB cable is to be used with their Windows “PowerChute” software for managing the UPS. I have an older APC “Back-UPS” (BN-650) model with the USB Type-B connector and it too is to be used with PowerChute software, but I don’t use PowerChute, I use NUT and it works with NUT just fine. So I think your unit will likely work with NUT using the RJ45 to USB cable, my only reservation is what driver will be used? Mine uses usb-hid, but I’m not sure what driver NUT will need with the RJ45-to-USB cable.

It’s the same driver.

Hi. Just wanted to confirm the APC by Schneider Electric (BACK-UPS ES - BE850G2-UK( arrived yesterday and came with an RJ45/USB cable included in the box. I was able to set up the UPS and it’s now working as hoped with Home Assistant and all sensors/diagnostics are being reported correctly.

Thanks to everyone for your guidance and advice, much appreciated.

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