Mac Network UPS Setup

UPS Power Monitor

I’m working from home more, so with money, I was given for my birthday, I purchased a new UPS to allow me to perform an orderly shutdown in the event of a power-cut. I choose an APC 850VA unit and was impressed at the construction and design of the unit.

I was however severely underwhelmed by APCs poor PowerChute software for Mac.

So I looked in the Mac App Store and came across “UPS Power Monitor”, which can monitor a UPS connected to a Synology NAS.

This software is £2.99, if it works super cheap, so I went ahead and purchased it.

Then I realised that it only runs the newest operating systems and not on my High Sierra i5 iMac from 2011, which I use as a monitor through target display mode.

As I continued however I realised that this was not a problem.


On my Big Sur i7 iMac, I ran the following to install “Power Guard”

/bin/bash -c "$(curl -fsSL" 

and on my High Sierra i5 iMac, I ran the following

/bin/bash -c "$(curl -fsSL"

which allows my i7 iMac to inform my i5 iMac to shutdown.


Now is the £2.99 app, I tell it where my Synology is and where any other remote MacOS machines I want to shutdown are, and at what % battery to shut-down at.

UPS Monitor StatsWith this done, I had to wait for the battery to charge to 100% after playing.

I set the “Monitor” i5 iMac to shut-down when the battery reached 95%, so it will last a good couple of minutes before disappearing and set the main i7 iMac to 30%.

This is that in a power cut I am willing to lose the 2nd Monitor in order to last longer on battery-backed power.

So test successful, the i5 iMac was shutdown down i7 is monitoring the UPS and waiting for 30%.


Success! But how difficult was this to do on the Synology end?

Synology UPS Config


Quite literally plug the monitoring cable from your UPS (RJ50 to USB) into your synology.

Log in as an admin and enter the control and select “Hardware & Power”

Switch to the UPS tab.

Tick to enable UPS support, until battery low. Tick enable UPS server and add the IPs of your Synology NASs and Macs that you want to be able to access the NUT server.

Then click save and you’re done!


Author: Andrew

2 thoughts on “Mac Network UPS Setup

    1. PowerGuard allows a signal to shutdown your MacBook or iMac. The UPS Helper monitors the level of battery from Synology, which is plugged into the APC via USB, over the network, and if it’s level drops below that which you specify, it tells powerguard to shutdown the machine over the network.
      In this instance if my power goes, UPS-Helper quickly shuts down my 2nd iMac, which I only use as a monitor, and later the main iMac. Only the main machine needs to run the UPS_Helper app, but powerguard runs on both iMacs so they can be shutdown over the network.

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