1. Flash & Boot your Pi

1. Flash Raspberry Pi OS Lite (64-bit recommended) to an SD-card.
2. Enable SSH (create empty ssh file in /boot).
3. Power up, ssh pi@<local-ip> and update:
   • sudo apt update && sudo apt full-upgrade -y

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2. Plug-in & Identify the UPS

Connect the UPS via USB and run:

lsusb

Look for a line like
Bus 001 Device 00X: ID 051d:0002 American Power Conversion …
Note the VendorID (051d) & ProductID (0002).

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3. Install NUT on the Pi

sudo apt install nut nut-server nut-client

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4. Configure the UPS driver

Edit /etc/nut/ups.conf:

sudo nano /etc/nut/ups.conf

Paste (adjust IDs if different):

[myups]
    driver = usbhid-ups
    port   = auto
    desc   = "APC Back-UPS 950VA"
    vendorid = 051d
    productid = 0002

Save (Ctrl+O, Enter, Ctrl+X).

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5. Create NUT users

Edit /etc/nut/upsd.users:

sudo nano /etc/nut/upsd.users

[admin]
    password = secret
    actions  = SET
    instcmds = ALL

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6. Tell NUT to act as a server

Edit /etc/nut/nut.conf:

sudo nano /etc/nut/nut.conf

Change:

MODE=netserver

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7. Allow LAN clients

Edit /etc/nut/upsd.conf:

sudo nano /etc/nut/upsd.conf

Add:

LISTEN 0.0.0.0 3493

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8. Start services

sudo systemctl restart nut-driver@myups
sudo systemctl restart nut-server
sudo systemctl enable nut-server

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9. Firewall (optional)

Open port 3493:

sudo ufw allow 3493/tcp

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10. Quick smoke-test from Pi itself

upsc myups@localhost

You should see a long list of UPS variables.

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11. Install Windows client

1. Download WinNUT-Client from
   https://github.com/gawindx/WinNUT-Client/releases
   (choose the .exe installer).
2. Run the installer → reboot if needed.

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12. Configure WinNUT

1. Launch WinNUT-Client.
2. Connection tab:
   • Host: <ip-of-your-pi>
   • Port: 3493
   • Username: admin
   • Password: secret
   • UPS Name: myups
3. Shutdown tab → set battery %, runtime, etc.
4. Click Save & Connect; status should turn green.

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13. Pull-the-plug test

1. Unplug the UPS from mains (keep USB cable).
2. Within seconds WinNUT should show On Battery.
3. After your configured thresholds, Windows will gracefully shut down.

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14. (Optional) Pretty web dashboard on the Pi

sudo apt install apache2 nut-cgi
sudo nano /etc/nut/hosts.conf

Add:

MONITOR myups@localhost "APC on Pi"

Restart Apache:

sudo systemctl restart apache2

Visit http://<pi-ip>/cgi-bin/nut/upsstats.cgi

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15. Done!

Your Pi is now the NUT master and Windows the client.

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One-line Service Restart

sudo systemctl restart nut-driver@myups && sudo systemctl restart nut-server