myenergi’s Zappi is popular with EV owners—especially households with solar—because it can intelligently divert surplus generation into your car, helping you charge greener and often cheaper.
By Gustavoblalmiras • Last updated: March 2026
This is only for educational purposes.
But “smart” chargers 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—red lights, tripping breakers, or unfamiliar fault messages—it can feel confusing fast.
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 myenergi’s official help articles and manuals.
Safety note (important): If you see repeated tripping, burning smells, heat damage, melted accessories, or any PEN/PE/earth-related fault, stop using the charger and contact a qualified electrician/installer or myenergi support. Don’t open the unit or work on fixed wiring unless you’re properly qualified.
Quick triage (do this first)
- Read the exact on-screen message (don’t rely on LED colour alone).
- Check the myenergi app for warning details (yellow triangles, offline status, CT errors).
- Decide if it’s a safety stop: repeated RCD/MCB trips, PE/PEN faults, overheating in mild weather, or any burning smell = stop and call a pro.
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 consistently in a repeatable pattern (immediate / at start / after 5–20 minutes)
Why it happens
Repeated tripping can be caused by the installation (earthing/insulation/leakage), the EV, supply issues, or (less commonly) charger hardware. It’s a safety event that needs proper testing—not guesswork.
What you can do safely
- Note when it trips: immediately on plug-in, at charge start, or after several minutes.
- Try once in another mode (FAST vs ECO) to see if behaviour changes (helps diagnosis, not a “fix”).
- If it’s repeatable: stop using the charger and arrange an installer/electrician check.
When to call an electrician
Any repeated RCD/MCB trip needs professional investigation. An electrician/installer can test insulation resistance, earth leakage, correct protective devices, and supply integrity.
2) Red light / status LED warnings (don’t ignore these)
A red LED understandably worries people. If you see a solid/flashing red indication, your next step is to check the app or device screen for the exact warning/fault message.
Symptoms
- Solid red or flashing red status LED
- Charging stops or won’t start
- App shows warnings or device appears “offline”
What to do
- Open the myenergi app and record the exact fault/warning text.
- If it looks like a connectivity glitch, follow the reboot guidance in section 5.
- If it returns quickly or shows any PE/PEN/earth fault: stop charging and contact your installer/myenergi support.
3) PEN Fault / PE Fault / “earth not connected” (installation and safety checks)
Zappi has built-in safety checks that can stop charging if it detects a dangerous earthing condition.
PEN Fault
What it means
If Zappi detects a problem with the PEN conductor, it can disconnect output and display a PEN fault message for safety.
What to do
Treat it seriously: stop charging and contact your installer/electrician. Only reset after a competent person confirms the installation/supply is safe.
PE Fault / “PE not connected”
What it means
This relates to Zappi’s protective earth continuity/impedance checks. If earth continuity is missing or impedance is too high, Zappi can stop charging and display a PE-related fault.
What to do
Stop charging and contact your installer/electrician. PE issues are safety-critical. Avoid DIY checks that involve opening the consumer unit or fixed wiring.
4) “Check Grid CT” / “Grid CT Lost” / solar diversion not working (CT clamp issues)
If you bought Zappi mainly for solar charging and ECO+ behaves 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 like Check Grid CT, Grid CT Lost, or Installation Limit
Most common root causes
- CT clamp on the wrong cable
- CT orientation reversed
- Loose connection at the Zappi/Harvi side
- CT and Zappi installed on different “sides” of a system (for example, if a voltage optimiser exists)
What you can do safely
- Check in-app import/export readings at a time you know generation/usage is changing.
- If CT clamps are accessible without opening electrical enclosures, visually confirm they are fully closed and not damaged.
- If anything requires opening a consumer unit, meter cabinet, or sealed enclosure: stop and contact your 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.
Symptoms
- Yellow triangle in the app (data may be out of date)
- Device shows connected on Wi-Fi but the 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 (brick/garage walls are tough)
- Router changes (new SSID/password, band-steering issues)
- Hub/cloud communication issues
Fixes that work most often
- Improve coverage: mesh node/extender near the garage (best long-term fix).
- Reboot Zappi using myenergi’s official method (stop charging first).
- Reconnect Wi-Fi using the official reset/reconnect flow if your router details changed.
6) Hub red light / “No response from server” (cloud connection issues)
If you’re using a myenergi hub (or relying on cloud features), hub/server connectivity can be the culprit.
Symptoms
- Hub LED shows red / server error
- 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 the hub status guidance).
- Reboot router and hub/device as recommended.
- If it’s persistent, log a support ticket—some issues can be service-side.
7) Over Voltage / Under Voltage faults (supply quality issues)
Sometimes the charger isn’t the problem—the grid is. Zappi can stop charging if it detects voltage outside allowed range and may auto-recover when voltage stabilises.
Symptoms
- Charging stops and shows Over Voltage / Under Voltage / Bad Voltage Range
- Faults happen at peak times (evenings) or during storms
What to do
- If it happens occasionally and clears: note the time and frequency.
- If frequent: ask your electrician/installer to check supply integrity and consider logging voltage over time.
8) Overheating / thermal limiting (hot garage, heavy charging, poor airflow)
Zappi has thermal protection. If the unit gets too warm, it may reduce current and can stop charging until it cools.
Symptoms
- Charging slows down unexpectedly
- “Overheating!” message
- Unit area feels unusually hot (warm can be normal; “too hot to touch” is not)
Practical fixes
- Improve airflow around the charger (don’t box it in).
- Avoid tightly coiling cables near the unit (heat build-up can worsen).
- If overheating happens in mild weather, stop using it and get the installation checked.
9) Contactor/relay faults and “RLY WELDED” (rare, but important)
This is uncommon, but serious when it happens. If you see “RLY WELDED!” and it persists after the official reset steps, treat it as a stop-and-call-support event.
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 managed charging service (for example, Intelligent Octopus Go), you can run into “why is ECO+ ignoring my solar?” confusion.
What’s happening
When a tariff/app (and sometimes the vehicle) is in full control of charging, it may not be aware of your solar surplus—so solar diversion behaviour may not work the way you expect in that setup.
What to do
- Decide the priority: tariff-optimised charging vs solar-divert charging.
- Follow myenergi + your energy provider guidance for that integration and configuration.
Common Zappi fault messages (plain-English cheat sheet)
| Message | Meaning (plain English) | What to do |
|---|---|---|
| PEN Fault! | Possible PEN/supply earthing fault detected. | Stop charging. Contact installer/electrician. |
| PE not connected! / PE Fault | Earth continuity/impedance problem detected. | Stop charging. Contact installer/electrician. |
| Check Grid CT / Grid CT Lost | Grid CT setup/reading issue affecting import/export data. | Do safe visual checks; otherwise contact installer. |
| Over Voltage! / Under Voltage! | Supply voltage outside allowed range. | Log frequency; if frequent, electrician/DNO investigation. |
| Overheating! | Thermal protection triggered. | Improve airflow; if repeat in mild weather, call installer. |
| RLY WELDED! | Contactor/relay welded detection. | Stop and contact myenergi/installer. |
A safe troubleshooting checklist (owner-friendly)
- Record the exact message on the Zappi screen (photo helps).
- Check the app for warning details (yellow triangles, CT errors, offline status).
- If it looks like a connectivity glitch, reboot Zappi using the official method.
- If solar divert is wrong, 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 / PE Fault condition
- RLY WELDED or persistent internal fault messages
- Overheating messages in normal temperatures
- Burning smell, discoloration, heat damage, or melted accessories
FAQ
Is Zappi reliable?
Generally yes, but many reported “problems” are caused by installation variables (earthing, CT placement) and connectivity/software—common across smart chargers.
Why is my Zappi not using excess solar in ECO+?
Most often it’s a Grid CT reading issue (placement/orientation/connection), or a managed charging integration is controlling charging and isn’t using solar diversion the way you expect.
What does “PE Fault” mean on Zappi?
It relates to Zappi’s protective-earth continuity/impedance checks. Treat it as safety-critical and get the installation assessed by a qualified person.
About the author
Gustavoblalmiras publishes practical driver and EV ownership guides at DriversAdvice.com. For corrections or updates, please use the site contact page.