Why is my ZEB charging at less than 9 kW?

Use this article to:

• Understand why ZEB may charge at less than 9 kW
• Learn how your electrical installation and end‑of‑charge tapering affect the rate of charging
• See when this behaviour is normal and when to contact support

Electrical supply constraints

The actual rate of charging can be limited by your electrical installation or incoming supply.

Examples include:

• Lower than nominal supply voltage
• Other large electrical loads in the home running at the same time
• Fuse or breaker limits on the ZEB circuit

In these situations, ZEB will respect the limits of your electrical supply, which can result in a charging rate below 9 kW.

End‑of‑charge tapering

As ZEB approaches its target state of charge, it may gradually reduce the rate of charging instead of staying at maximum until the very end.

This tapering:

• Improves safety
• Supports long‑term reliability of the system
• Means the final part of the charge will naturally be slower than the initial phase

It is therefore normal to see a lower charging rate as ZEB nears its target.

Is this behaviour normal or an issue?

Charging at less than 9 kW is usually expected behaviour, especially if:

• ZEB is already at a moderate or high state of charge
• The reduced charging rate occurs towards the end of a charging period

If you are concerned there may be an issue, check:

• The state of charge (SoC) when you noticed the lower rate of charging
• Any warnings or errors in the app or on the unit

If ZEB still seems to be charging too slowly after these checks, or consistently fails to store enough energy to meet your comfort needs, please contact support with:

• A brief description of the issue
• The times and dates when you observed a lower rate of charging
• Screenshots of the relevant charge graphs and settings (if available)

This will help us determine whether what you are seeing is within normal operating behaviour or requires further investigation.