This is a FOSS project that supports to connect a charger for an electric vehicle (EV) with a photovoltaic generation system.

Using these two things in combination is much more economical than using them separately: The PV system provides energy to the EV that is much cheaper than electricity from the grid. In addition, using the car’s battery makes the PV installation more useful - it could also serve to store extra energy for the house.

But why open source? In many areas, vendors try to sell integrated systems, trying to get higher prices. And customers sometimes like the convenience.

But here, there are clear advantages to open systems with open Interfaces:

• You don’t want to buy a new car when you move house or get a new home battery.
• You might want to start with an ultra-cheap balkony solar panel which you can put just on top of your garage. And later you might want to install a heat pump when you have the money or subsidies are available. This requires flexibility, which integrated systems ain’t (ever tried to add more RAM to your old Macbook?)
• Technology is changing at a rapid pace. Especially battery prices are falling fast. So, things like extra batteries for the house will become economically interesting long before your car reaches its end of life.
• The cost structures: For rooftop solar, costs for plumbing and electrical installation are already often the most exoensive part. Prices for solar panels are falling rapidly along an exponential curve.
• Software quality: While home power systems often provide great hardware, the software quality is often pretty shite. (My brother just confirmed that, he bought a heat pump and its Modbus interface does not match documentation…).
• Complexity: Charging a car from the grid, at a fixed price, is not so complicated. But taking into account battery storage, variable solar production and dynamic prices makes this a complex task. Plus, every household has different individual needs. Pre-canned systems are unlikely to get the most out if it.
• Breadth of hardware support: Panels, cars, wall boxes, inverters, batteries, controls: There are thousands of components on the market. Hardware vendors can however usually only support a few interfaces. Interacting with every common piece of hardware is beyound their capabilities, and impossible to fit to their business model. Open source in contrast can muster the manpower (and womanpower) to make many things work, as the Linux kernel shows.

Open source is a collaborative project, where many people contribute to something which is much more than the sum of its parts.

Enters the transition to renewable energy. Bidding farewell to fossil energy is urgently needed to ensure our survival as a human civilization. And if you think about it, it is perhaps the biggest and most far-reaching technical endeavour since the invention of fire. In future, we must survive and operate without burning things (or liquids), and this is not a small feat, as it means re-inventing so many things we do. Nobody can do this alone. We’ll need every intelligent person and every alive brain cell to get there.