This charger enables you to drive your EV without worry. It is frequently regarded as the finest alternative for households with solar panels. That’s because myenergi’s Zappi is designed to intelligently divert surplus solar (or other generation) into your car, letting you charge greener and (often) cheaper.
But “smart” chargers also have more moving parts than a basic wallbox: CT clamps, safety checks, firmware, Wi-Fi/cloud connectivity, and interactions with your car and tariff apps. When something goes wrong, it can feel confusing—especially when the unit shows a red light or throws fault messages you’ve never seen before.
This guide covers the most common Zappi charger problems, what the symptoms look like, what typically causes them, and the safest, most practical fixes—based on official myenergi support guidance and installer manuals.
Safety note (important): If you see repeated tripping, burning smells, heat damage, or any PEN/PE/earth-related fault, stop using the charger and contact a qualified electrician or myenergi support. Don’t open the unit or work on fixed wiring unless you’re properly qualified.
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1) Upstream RCD/MCB tripping (charger won’t stay powered)
One of the most common complaints is: “My Zappi trips the breaker/RCD when I plug in” or “It charges for a few minutes, then trips.”
Symptoms
- The consumer unit RCD/MCB trips when charging starts
- Charging stops suddenly and Zappi loses power
- Trip happens more in certain modes (FAST vs ECO/ECO+)
Why it happens
Myenergi notes there are many possible causes: some internal to Zappi (hardware failure), and some external (installation/wiring faults, vehicle-related leakage, supply issues).
What to do (safe checks)
- Try a different charging mode (FAST vs ECO) to see if it’s consistent (helps diagnosis, not a “fix”).
- Note when it trips: immediately on plug-in, at charge start, or after 5–20 minutes.
- If it’s repeatable, stop using it and get the install checked.
When to call an electrician
- Any repeated RCD/MCB trip is a safety event. Myenergi’s guidance is clear that causes can be external or internal, and you want a professional to test insulation/earth leakage and confirm correct protection devices.
2) Red light / Status LED warnings (don’t ignore these)
A red LED on Zappi understandably worries people. Myenergi’s own LED guidance is blunt: if you see a solid or flashing red light, investigate in the app or contact support.
Symptoms
- Solid red or flashing red status LED
- Charging stops or won’t start
- App shows warnings or device appears “offline”
Likely causes
- A real electrical fault (earth/voltage/contactor)
- Connectivity faults (hub/cloud)
- Internal warnings that require a reboot or support ticket
What to do
- Open the myenergi app and check the exact fault/warning text.
- If the unit is unresponsive, perform a controlled reboot (see section on app/yellow triangle below).
- If it returns quickly, don’t “keep trying”—collect the fault code/message and contact support.
3) PEN Fault / PE Fault / “earth not connected” (installation and safety checks)
Zappi includes safety features many basic chargers don’t. In the installer manual, myenergi explains that Zappi has built-in protection for PEN conductor faults and can disconnect the output if it detects a problem, which can remove the need for an additional earth electrode in relevant installations.
PEN Fault
What it means
If Zappi detects a problem with the PEN conductor, it will show “PEN Fault!” and disconnect output. The manual advises checking earth continuity before reset.
Why it happens
- Supply/earthing fault conditions
- Fault currents suggesting unsafe conditions
- Installation or network issues (rare, but important)
PE Fault / “PE not connected”
Myenergi’s support article explains the PE check is an advanced safety feature that measures earth continuity/impedance, and in some cases may need adjustment.
The installer manual also notes Zappi can trip if earth is disconnected or has high impedance, showing “PE not connected!”
What to do
- Treat PEN/PE faults seriously: stop charging and call your installer/electrician.
- If you’re told to reset, follow official instructions—but only after a competent person confirms the installation is safe.
4) “Check Grid CT” / “Grid CT Lost” / solar diversion not working (CT clamp issues)
If you bought Zappi mainly for solar charging and ECO+ is behaving like it’s blind to your PV, CT clamps are the first suspect.
Symptoms
- ECO+ never uses surplus solar
- Export/import readings look wrong or “flat”
- Errors such as Check Grid CT, Grid CT Lost, or odd limits triggering
Myenergi’s support explains that a damaged/unplugged CT can cause missing or unstable data and recommends checking secure connections or replacing the CT if faulty. Improper installation or loose fittings can also create inaccurate measurements.
Most common root causes
- CT clamp installed on the wrong cable
- CT orientation wrong (reversed direction)
- Loose connection at the Zappi/Harvi side
- CT and Zappi not measuring the same “side” of a system (e.g., a voltage optimiser)
The full manual also highlights that if a voltage optimiser exists, the CT sensor and Zappi must be on the same side of it.
What you can do safely
- Check in-app readings (import/export) at a time when you know you’re generating or using power.
- If your CT clamps are accessible without opening electrical enclosures, visually confirm they are properly closed and not damaged.
- If anything requires opening the consumer unit or meter cabinet: stop and call the installer.
5) App not updating, yellow warning triangles, Wi-Fi dropouts
A surprisingly common “problem” is that charging works—but the app shows warnings, delayed data, or a yellow triangle.
Myenergi’s help centre covers yellow warning triangles and suggests improving Wi-Fi coverage and rebooting the device. For Zappi, it gives a reboot method: stop charging, press menu once, then hold menu to reboot; if needed, isolate power briefly (typical guidance is around 30 seconds).
They also provide step-by-step instructions to reset and reconnect a myenergi device to Wi-Fi, including connecting to the device’s access point and confirming “Connected” status.
Symptoms
- Yellow triangle in the app (data may be out of date)
- Device shows connected on Wi-Fi but app says offline
- Stats freeze, schedules don’t sync, or “EV not connected” appears incorrectly
What usually causes it
- Weak Wi-Fi signal at the charger location (garage walls and brick are brutal)
- Router changes (new SSID/password, band steering issues)
- Cloud/hub communication problems
Fixes that work most often
- Improve coverage: mesh node, extender, or reposition router (best long-term fix).
- Reboot the Zappi following myenergi’s steps.
- Reconnect Wi-Fi using myenergi’s official reset/reconnect flow.
6) Hub red light / “No response from server” (cloud connection issues)
If you’re using a myenergi hub (or relying on the ecosystem), hub/server connectivity can be the culprit.
Myenergi provides a specific troubleshooting article for Red Light on hub / No Response From Server, including typical causes (no IP address vs no data from myenergi server) and the usual remedies such as rebooting router/device and checking Ethernet.
Symptoms
- Hub LED red
- App shows stale data or devices disappear
- Zappi works locally but app features fail
What to do
- Confirm your router is online and the hub has an IP address (per myenergi guidance).
- Reboot router and hub/device as recommended.
- If it’s persistent, log a support ticket—server communication issues can also be service-side.
7) Over/Under Voltage faults (supply quality issues)
Sometimes the charger isn’t the problem—the grid is.
The installer manual states that Zappi will isolate the supply to the EV if it detects voltage more than 12% above or below nominal (230V) for five seconds, showing “Over Voltage!” or “Under Voltage!” and will automatically reset once voltage returns to acceptable range.
Symptoms
- Charging stops and shows Over Voltage / Under Voltage
- Faults happen at peak times (evenings) or during storms
Likely causes
- Local supply fluctuations
- Loose connections (needs professional investigation)
- High load on your home circuit affecting voltage stability
What to do
- If it happens occasionally and clears: note the time and frequency.
- If frequent: ask your electrician to check supply integrity and consider logging voltage data (your installer may do this).
8) Overheating / thermal limiting (hot garage, heavy charging, tight cable routing)
Zappi has built-in thermal protection. The manual explains it will attempt to reduce current if it gets too warm, and if temperature continues to rise, it can trip output and show “Overheating!” then resume once cooled.
Symptoms
- Charging slows down unexpectedly
- “Overheating!” message
- Charger area feels unusually hot (warm is normal; “too hot to touch” is not)
Common causes
- Direct sun on the unit
- Poor ventilation
- High ambient temperatures plus continuous high-current charging
Practical fixes
- Improve airflow around the charger (don’t box it in).
- Avoid running tightly coiled extension/charging cables near heat sources.
- If overheating happens in mild weather, get the installation checked.
9) Contactor/relay faults and “RLY WELDED” (rare, but important)
This is not common, but it’s serious when it happens. The installer manual notes that if Zappi detects a welded contact, the display shows “RLY WELDED!” and advises contacting myenergi technical support if it can’t be reset.
Symptoms
- Fault message RLY WELDED
- Charging will not start or stops immediately
- Persistent fault after resets
What to do
- Stop using the charger and contact myenergi support or your installer.
10) Smart tariff integrations (charging “fights” your solar settings)
If you use a smart tariff/managed charging service, you can run into “why is ECO+ ignoring my solar?” confusion.
Myenergi’s help article about zappi & Intelligent Octopus Go states that when Octopus (and the car) are in full control of charging, they’re unaware of solar generation—so solar divert isn’t expected to work in that mode.
Symptoms
- Zappi won’t behave like ECO+ during managed charging
- Solar surplus appears available but Zappi doesn’t ramp charging
What to do
- Decide what’s the priority: tariff-optimised charging vs solar-divert charging.
- Use the configuration recommended by your energy provider and myenergi’s guidance for that integration.
Common Zappi fault messages (plain-English meanings)
These are some of the key messages you might see, straight from myenergi documentation:
- PEN Fault! → Potential supply PEN conductor issue; unit disconnects output for safety.
- PE not connected! → Earth continuity/impedance problem detected.
- RLY WELDED! → Contactor/relay welded detection; contact support.
- Over Current! → EV drawing too much current; Zappi isolates for protection.
- Over Voltage! / Under Voltage! → Supply voltage out of range; may auto-reset when stable.
- Overheating! → Thermal protection triggered; resumes after cooling.
A safe troubleshooting checklist (owner-friendly)
Use this if something feels “off,” but you don’t want to guess:
- Read the exact on-screen message (don’t rely on LED colour alone).
- Check the app warning details (yellow triangles, offline status).
- Reboot the Zappi using myenergi’s official method if the system is glitchy.
- If solar divert isn’t working, review Grid CT readings and errors.
- If you see PE/PEN faults or repeated breaker trips, stop and call a qualified electrician.
When you should stop troubleshooting and call a pro
Call your installer/electrician (or myenergi support) immediately if you have:
- Repeated RCD/MCB tripping
- Any PEN Fault / PE not connected condition
- RLY WELDED or persistent internal fault messages
- Overheating messages in normal temperatures
- Burning smell, discoloration, or melted accessories (stop using immediately)
FAQ
Is Zappi reliable?
Generally yes, but most reported “problems” come from installation variables (earthing, CT placement) and connectivity/software—common to many smart chargers. Official support guidance focuses heavily on CT errors, connectivity, and upstream protection trips.
Why is my Zappi not using excess solar in ECO+?
Usually because the Grid CT isn’t reading correctly (installation/orientation/connection) or because a managed charging integration (like Intelligent Octopus Go) is controlling charging and is unaware of solar diversion.
What does “PE Fault” mean on Zappi?
It relates to Zappi’s protective-earth continuity/impedance checks. Myenergi notes it’s an advanced safety feature and may sometimes need adjustment in specific cases—your installer should assess it.
One honest note about sources
I attempted to capture screenshots of the official PDF manuals using the web tool’s PDF screenshot feature, but the tool returned a validation error. I still used the manuals’ text extracted via the web viewer for the fault-message definitions and safety behaviors.