Zappi shows E004 and will not charge, often after a power cut or grid disturbance

Safety first: Voltage issues can damage equipment. Do not attempt to modify supply voltage yourself.

• 1. Observe when E004 occurs: Note if the error appears only during certain times (e.g. heavy local load, storms). This can indicate grid issues.
• 2. Measure supply voltage: Have an electrician measure line-to-neutral voltage at the Zappi terminals under load. It should typically be around 230 V ±10% in many regions.
• 3. Check neutral and line terminations: With power off, inspect and tighten the line and neutral terminals in the Zappi and at the consumer unit. Loose neutrals can cause over/undervoltage.
• 4. Inspect for signs of overheating: Look for discoloration or melting around the main terminal block, which may indicate poor connections.
• 5. Power-cycle and retest: After tightening and inspection, turn the supply back on and attempt a charge. If E004 persists with stable measured voltage, the voltage sensing circuit on the main PCB may be faulty.
• 6. Contact utility if needed: If the supply voltage is consistently outside specification, contact your electricity provider to investigate.