"Granny charging" (using a standard 3-pin wall plug) is actually great for the long-term health of your EV battery. Because it delivers a slow, low-amperage charge, it generates very little heat—the biggest enemy of lithium-ion batteries. 

However, while gentle on your car, it can be dangerous for your home's electrical system if not managed properly. 

Battery Health: The Good
  • Minimal Degradation: Slow trickle charging prevents the microscopic damage and strain caused by rapid public charging or high-capacity home wallboxes. 

    Household Safety: The Risks
    • Socket Overheating: Standard household wall sockets and wiring were not designed to handle a continuous 10-to-13-amp draw for 8 to 12 hours straight. Plugs and sockets can heat up and melt if they are old or worn. 

Best Practices for Granny Charging
  1. Plug Direct: Always plug the charger directly into a heavy-duty, properly grounded wall socket. 


  • Professional Check: If you intend to use a 3-pin plug regularly, have a qualified electrician inspect the socket and circuit to ensure it is rated for continuous EV loads. 
    • While perfectly fine for plug-in hybrids (PHEVs) or occasional top-ups, relying on a granny charger for large EV batteries can be incredibly slow and inefficient. For more safety guidelines, check out the Joosup Granny Charger Guide. If you plan to charge frequently at home, look into having a professional install a dedicated 7kW home charging point.