Auxiliary Powerswitch

Auxiliary Powerswitch

Don’t worry about power shortages anymore

Project Description

Motivated by the high energy costs, I wanted to add a secondary (auxiliary) power source.
As I’m driving a Tesla MS with free SuC, the idea was to use my car as fallback power source in case the solar panels on my roof do not generate enough energy to charge up the battery in my house.
The reason for choosing a separate powerswitch instead of adding another charger are simply the costs and the fact that if there is sufficiently solar power, the other power sources are not needed.
With this solution I’m now also able to extend the energy storage with my Ebike’s batteries by simply adding them as an additional input, charging if there is enough solar power and discharging when needed.


  • 25A maximum current
  • WAGO connectors for easy cable installation
  • Temperature sensors on pcb to monitor traces
  • Controllable via REST API
  • Status LED indicating state of operation
  • Galvanically isolated

Source code, schematics and cad drawings: