Hi all,
I would like to share a project I have been running at home for a few weeks: Home EV Solar Control (HESC), a Home Assistant package with a Node-RED flow. In short: HESC makes sure your EV has the charge you want at the time you want, charged the cheapest way, with sun and grid.
It is free and open source (GPL-3.0): github.com/satscan1/home-ev-solar-control
Why I built it
At home two batteries are controlled by Home Battery Control (HBC). To prepare for the end of net metering in the Netherlands in 2027, I added Home PV Control (HPVC), which turns the panels down when exporting costs money.
The side effect: on exactly those sunny moments the car did not charge. The solar mode of most wallboxes only starts when the house exports power, and HPVC made sure there was no export. HESC started as the fix for that: it asks HPVC for a temporary release so the sun can go to the car. Since then it has grown into a standalone solution that also works without HPVC, and even without solar panels.
What it does
- Charging on sun: follows every solar session and compares it with the forecast, so you see how much of the car’s energy came from the sun.
- Charge plan: “100% by Tuesday 10:00” or “80% on weekdays at 07:30”. HESC picks the cheapest quarters before that moment, counts on the sun that is still coming, and has a safety net so the car is ready on time.
- Cheap chances and minimum charge: optional extra charging at very low prices, and a minimum level after coming home with an almost empty battery.
- Shadow mode: a new install evaluates and logs everything, but switches nothing. You can see what HESC would do before you let it act.
- Advice and a report in plain language, based on your own history.
- No InfluxDB needed: the history is kept in its own file.
The dashboard
HESC comes with its own dashboard with three tabs. The numbers are explained in The dashboard explained.
Main: status, live inputs and the solar forecast against what really happened.
Charge plan: one-off and weekly plans, and the price chart with the planned quarters.
Settings: pick your charger type and HESC fills in the rest. One setup check shows straight away whether everything works.
What you need
- Home Assistant with packages enabled, and Node-RED with the Home Assistant nodes
- An EV charger in Home Assistant with a solar or eco mode
- For charging on sun: solar panels and a forecast in watts (Solcast works best)
- For the charge plan: a day-ahead price sensor with raw_today and raw_tomorrow attributes, like Nord Pool. Charging on sun also works with a fixed tariff.
- Optional: HPVC v1.5.1 or newer, a weather station, the battery level of the car
Chargers
HESC does not control the charger itself: it uses the solar mode your charger already has. Mappings are ready for Wallbox Pulsar Plus, Alfen Eve, Peblar, myenergi Zappi, go-e, Fronius Wattpilot, SMA EV Charger, Ohme and Easee. Only the Wallbox Pulsar Plus has been tested in practice. If you try another brand, please start in shadow mode and let me know how it goes, so the list can grow.
Install
Copy the package into /config/packages, restart Home Assistant, import the Node-RED flow, add the dashboard and fill in step 1 of the Settings tab. The full guide is in docs/01-installation.md.
Feedback, questions and experiences with other chargers are very welcome, here or as an issue on GitHub.
Project on GitHub: github.com/satscan1/home-ev-solar-control