suburban

Home energy monitor for the suburbs

I live in a house in suburban Sydney. It has an electrical load setup that is quite typical. The main ones are:

• 10kW (10kW inverter, 13kW panels) solar system.
• Pool with a chlorinator (needs to be run a few hours a day).
• plugin hybrid car (18kWh battery)
• gas hot water (for now)
• Reverse cycle AC

Rather than pay Fronius a monthly fee to monitor my usage, I'm doing it myself. The plan is to analyse usage over summer and winter and then start controlling some loads listed above with the Arduino. I did something similar years ago when I was in an apartment. Unfortunately the hardware didn't last. Might have been the DB load running off an SD card. Hopefully the 8yr old NUC does a better job.

Hardware

• Arduino Opta RS485
  • 2 Relays connected to 20A SSR to control loads
• Carlo Gavazzi EM112 Series Energy Monitor installed in main switchboard
• Fronius Gen24 Inverter
• Old Intel NUC (i3-7100U) I added a Battery! 50kWh for AU$3949. Thank you Federal Gov!
• Solplanet ASW5000H-S2 Hybrid inverter (no solar connected)
• 5 x Solplanet ASW5120-LB-G3

Software

• Arduino IDE (not the plc one)
• Linux Mint
  • Python
  • InfluxDB
  • Grafana
  • Cloudflare reverse proxy to connect from anywhere.

notes

1. Create run.sh file. Contents:

export INFLUXDB_TOKEN=<influxdb token>
python logger.py

2. Make it executable:

chmod +x run.sh

3. Start on boot with a systemd service (see below).

grafana dashboards

example_grafana_dashboard.json shows how to set up a dashboard with 2 y axes and aggregate function on query.

run logger as a systemd service

@reboot in crontab isn't reliable (no restart on crash, fires before the network is up). Use systemd instead. suburban-logger.service lives in the repo root; install it with:

sudo cp suburban-logger.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now suburban-logger.service

Useful commands:

systemctl status suburban-logger       # check it's running
journalctl -u suburban-logger -f       # tail logs
sudo systemctl restart suburban-logger # restart after code changes

daily log backup to GitHub

backup.sh stages everything under log/, commits, and pushes so the parquet/csv files are mirrored to the remote. suburban-backup.timer fires it once a day.

1. Make sure git push works non-interactively for the john user on the NUC. Either switch the remote to SSH (git remote set-url origin git@github.com:jash8506/suburban.git with a keypair in ~/.ssh) or configure a credential helper storing a personal access token (git config --global credential.helper store then push once by hand).

2. Install the unit files (they live in the repo root):

sudo cp suburban-backup.service suburban-backup.timer /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now suburban-backup.timer

Enable the timer, not the service — the timer triggers it. Persistent=true in the timer catches up a missed backup after boot; RandomizedDelaySec jitters the fire time off midnight.

Useful commands:

systemctl list-timers suburban-backup*        # next/last run
systemctl status suburban-backup.service      # last run result
journalctl -u suburban-backup.service         # output of past runs
sudo systemctl start suburban-backup.service  # run now, out of schedule

Misc

The Arduino reaches the network through an old D-Link DSL-2750B running OpenWrt, which joins the Wi-Fi and forwards port 80 on 192.168.0.144 to the Arduino; setup and recovery are in dlink/README.md.

For some reason, I needed to run this to allow the NUC to see the battery interface. sudo ip neigh replace 192.168.0.137 lladdr 94:51:dc:20:87:04 dev wlp58s0 OR also fixed by forcing my NUC to use the 2.4GHz band.

sudoers rule for the Solplanet wake-up ARP probe

logger.py:_wake_solplanet runs arping after a failed HTTPS request to refresh the AP's bridge FDB and unstick the Solplanet dongle. arping needs raw sockets, so it must run as root — and the systemd service can't answer a password prompt, so we install a NOPASSWD sudoers drop-in.

1. Confirm arping is installed and check its path (should match one of the entries in sudoers.d/suburban-logger):

which arping     # expect /usr/bin/arping or /usr/sbin/arping
# install if missing
sudo apt install iputils-arping

2. Install the drop-in (must be mode 0440, owned by root, or sudo refuses to load it):

sudo install -m 0440 -o root -g root sudoers.d/suburban-logger /etc/sudoers.d/suburban-logger
sudo visudo -c       # validates ALL sudoers files — if this errors, remove the drop-in before logging out

3. Smoke test that it really is passwordless (-n makes sudo fail fast instead of prompting):

sudo -n arping -c 1 -w 1 -I wlp58s0 192.168.0.137

4. Restart the logger so the new wake path is live:

sudo systemctl restart suburban-logger