When your electric car won’t charge, the fault is almost always one of five things: a loose or damaged cable, a tripped circuit breaker, a software glitch in the car or charger, a compatibility mismatch, or a battery protection response triggered by temperature. Work through the steps below in order and you will find the cause in most cases without calling an engineer.
Key Takeaways
- The most common cause of an EV refusing to charge is a cable not fully seated at both ends — check this first before anything else.
- A single tripped breaker in your consumer unit will stop all charging; reset it once and monitor whether it trips again.
- Software communication errors between the car and charger can usually be cleared by turning both off, waiting 60 seconds, and restarting.
- Extreme cold or heat triggers battery management system protection, which throttles or pauses charging automatically.
- If the car shows a battery fault warning on the dashboard, stop troubleshooting and contact your dealer — this is beyond home diagnosis.
Why Your EV Won’t Charge: The Five Most Likely Causes
The majority of charging failures reported by UK EV owners fall into one of these categories, ranked by how often each occurs:
- Cable or connector fault — loose, damaged, or incompatible
- Tripped circuit protection — MCB, RCD, or RCBO at the consumer unit
- Software or communication error — firmware glitch, scheduling conflict, or pilot signal failure
- Compatibility issue — charger and vehicle not communicating correctly
- Battery management system response — temperature too low or too high, or charge limit already reached
Understanding which category your fault falls into tells you whether you can fix it yourself or whether you need a qualified EV installer.
Step-by-Step Diagnosis
Work through each step in sequence. Stop as soon as you find the fault.
Step 1: Check the Cable at Both Ends
Disconnect the charging cable from both the car and the charger (or wall socket). Inspect both connectors for:
- Bent or corroded pins
- Debris or moisture inside the socket
- Any visible damage to the cable jacket
Reconnect firmly at the charger end first, then at the vehicle end. You should feel a definite click or hear a locking confirmation. If the car has a charge port latch, confirm it has engaged.
If the cable is tethered to your home charger, inspect the connector end for damage and clean the pins gently with a dry cloth.
Step 2: Check the Consumer Unit
Go to your fuse box and look for a tripped MCB, RCD, or RCBO. A tripped device will sit in the middle position rather than fully on or fully off. Reset it by pushing it fully off, then back on.
If it trips again immediately, do not force it on again. This indicates an earth fault or short circuit — turn off the charger at its dedicated isolator and call your installer. Repeated resetting of a tripping breaker can cause further electrical damage.
If the breaker resets and holds, try plugging the car in again.
Step 3: Check Charge Limits and Scheduling in the App
Many smart chargers and EVs have charge limits (for example, an 80% cap set to preserve battery health) or scheduled charging windows that prevent charging outside set hours.
Open your charger app and check:
- Whether a scheduled charging session is active
- Whether a charge limit is set at or below your current battery level
- Whether the charger is showing as offline or in an error state
Also check your vehicle’s infotainment or EV settings for any charge limits set on the car side. These take precedence over the charger.
Step 4: Restart Both the Charger and the Vehicle
Turn off your charger at the isolator switch (usually mounted next to the unit) and wait 60 seconds. Then restart it. At the same time, turn the vehicle off completely — not just into standby — and restart it.
This clears most software communication errors. The pilot signal that handshakes between the car and charger can sometimes lock up after a firmware update, connectivity drop, or power fluctuation.
Once both have restarted, attempt to charge again.
Step 5: Test With a Different Cable or Charger
If you have access to a three-pin granny cable, try charging via a standard domestic socket. If the car accepts charge through the granny cable but not the home charger, the charger unit or its cable is the likely fault.
Conversely, if the car refuses charge through every source, including a public charger, the fault is almost certainly on the vehicle side — the onboard charger, charge port, or battery management system.
Step 6: Check for Error Codes
Most home chargers display error codes either on the unit itself (via LED patterns or a screen) or through the companion app. Look up the specific code in your charger’s manual or support pages.
Common codes and what they mean:
| Code type | Likely meaning |
|---|---|
| CP (Control Pilot) error | Vehicle not responding to handshake |
| Ground fault | Earth leakage detected — call installer |
| Over-temperature | Charger or cable too hot — allow to cool |
| No power | Supply fault or consumer unit issue |
| Authentication fail | RFID or app authorisation not completed |
Charging Problems by Scenario
”The charger light comes on but the car won’t start charging”
The charger is powered but the vehicle-to-charger handshake has failed. Most likely causes: charge limit already reached, a software glitch in either device, or a scheduling conflict. Work through Steps 3 and 4 above.
”The charger light stays off completely”
No power is reaching the unit. Check the consumer unit first (Step 2), then the charger’s dedicated isolator switch.
”Charging started but stopped after a few minutes”
The charger may have tripped on over-temperature protection, an earth leakage event, or a grid voltage fluctuation. Allow the unit to cool for 20 minutes, then retry. If it stops again at the same point, call your installer.
”My EV charges fine at public chargers but not at home”
The home charger is the fault. Check the unit’s error codes and app, and contact your charger manufacturer’s support team.
”The car shows a charging error on the dashboard”
Do not continue troubleshooting. A dashboard charging fault on the vehicle side — particularly a battery warning light — needs dealer diagnosis. In some cases these relate to the onboard charger unit, which is a manufacturer warranty issue.
When to Call an Installer
Stop troubleshooting and call a qualified EV installer or the emergency line of your charger manufacturer if:
- The consumer unit breaker trips every time you attempt to charge
- You can smell burning from the charger, cable, or consumer unit
- The charger or cable is visibly damaged or shows signs of heat damage
- The car shows a persistent battery or charging fault on the dashboard
- You have completed all steps above and the fault remains unresolved
Do not attempt to open or inspect the internals of a home charger unit. These contain live electrical components and must be serviced by a competent person under BS 7671 and the IET Wiring Regulations.
For a wider look at common EV charger faults and what they mean, the EV charger troubleshooting hub covers both home and public charging scenarios in detail.
Frequently Asked Questions
Why does my electric car say it’s charging but the battery percentage isn’t increasing?
This usually means the car is in a pre-conditioning or heating phase, drawing power to warm the battery before it begins accepting charge. It can also occur if a charge limit is set very close to the current state of charge. Wait 10 minutes and check whether the percentage begins to rise. If it does not, check the charger app for error states and restart both the charger and the vehicle.
Can a faulty charging cable damage my EV?
A visibly damaged cable with exposed wiring or corroded pins should not be used, as it can cause charging errors, blown fuses, or in rare cases earth leakage events. A cable that is simply loose or not fully seated will not cause damage — it will just prevent charging from starting. Replace any cable showing physical damage rather than attempting to continue using it.
My EV worked fine yesterday but won’t charge today — what changed?
The most common overnight changes that cause this are: a firmware update pushed to the charger overnight that has altered settings, a broadband outage that has taken the charger offline (relevant for smart chargers with scheduled charging), or a temperature drop that has triggered battery protection. Check the charger app for connectivity status and any update notifications, and confirm the consumer unit breaker has not tripped.
How long should I wait after restarting the charger before trying again?
Wait at least 60 seconds with the charger fully powered off at the isolator before switching it back on. Some chargers take up to 90 seconds to complete their boot sequence and re-establish a connection with the network.