EV charging

EV charging interrupted randomly

Warning Do not attempt any electrical or gas work yourself. Always use a qualified, MCS-certified, or Gas Safe registered professional for repairs.

What you’re seeing (symptoms)

You plug your car in and charging starts, but you wake up to find the car only partially charged. Your app may show several “Starting” and “Stopping” events throughout the night, or a message saying “Charging Interrupted.”

What’s normal vs not normal

Normal:

  • The charger pausing during the day if you have “Solar Matching” turned on and a cloud passes over.
  • The charger pausing for a few minutes if your house’s total power usage exceeds a safe limit (Load Balancing).

Not normal:

  • The session stopping and not restarting when there is plenty of power available.
  • Getting “Charge Failed” notifications on your phone every few minutes.
  • The charging cable feeling extremely hot to the touch when the session stops.

Likely causes (ranked)

  1. Poor cable connection: The Type 2 cable isn’t pushed fully into the car or the charger, leading to a break in the “pilot signal” that manages the charge.
  2. Vehicle “Deep Sleep”: Some EVs (especially older models) “go to sleep” so deeply that they stop communicating with the charger if there’s a delay in the schedule.
  3. Grid instability: Your local network voltage is fluctuating, causing the charger’s safety sensors to trip and reset.
  4. Overheating: The charger or the car’s internal inverter is getting too hot and pausing to cool down.
  5. Software conflict: Your car’s internal charging timer is fighting with your charger’s app schedule (e.g. car set to 1am, charger set to 2am).

Quick checks you can do safely

  • Check the cable: Ensure the cable is firmly “clicked” into both ends. Check the pins for any dirt, grit, or signs of burning.
  • Simplify the schedule: Turn off all schedules in both the car and the charger app. Try a “Charge Now” session to see if it remains stable.
  • Check the car’s app: Does the car show any error messages like “Check External Power Supply”?
  • Observe the charger: Watch the lights on the charger when it stops. Does it turn red or just go back to “Waiting”?

When to call an installer

  • If the “interruption” only happens when other large appliances (like a heat pump) are running.
  • If you find any melted plastic or scorch marks on your charging cable or the charger socket.
  • If your charger’s app logs show frequent “Low Voltage” or “Earth Fault” events.

Questions to ask your installer

  • “Is the CT clamp (load balancer) installed correctly and not ‘chattering’?”
  • “Can you check the ‘Signal Strength’ of the CP (Control Pilot) wire in the cable?”
  • “Are the terminals inside the isolator switch tightened to the correct torque?”

Related NetZeroNow tools & guides

FAQs

Is it my car or the charger? The best way to tell is to try a different cable (if your charger is socketed) or try a public AC charger. If the car charges fine in public, the issue is likely your home charger or its installation. Why does it stop at 80%? Many EVs have a “Target Charge” setting to protect the battery. Check your car’s infotainment screen to see if a limit has been set. Could it be my Wi-Fi? Usually no. Once a charge has started, most chargers will continue even if they lose Wi-Fi. However, some “Smart” tariffs (like Octopus Intelligent) require a constant connection to keep the charge authorized. Does the weather matter? Yes. In very hot weather, the car or charger may slow down or pause to prevent the battery from overheating. What is a ‘Handshake’? It’s the electronic conversation between the car and the charger. If this “handshake” is weak or interrupted (e.g. by a faulty pin), the charge will stop for safety.\n

Written by NetZeroNow | Last updated on 2026-03-02