Import Limit - TonyM1958/HA-FoxESS-Modbus GitHub Wiki

Updated firmware on newer inverters sets import limits. This measures the current and power at the grid CT clamp (Meter1 / CT1) and limits the power used by the inverter when charging the battery.

These settings are provided so you don't blow your supply fuse when charging your battery and running your normal house loads. Blowing your fuse is bad as you won't have any grid power and won't be able to restore power without calling out an engineer from your network supplier (DNO).

To know how to set your import limit, you need to understand:

• Your grid supply fuse rating. This is usually stamped on the fuse, where the supply cable enters. Common ratings are 60A, 80A or 100A. ENA are in the process of standardising installations at 80A. If you are not sure what your fuse rating is, you should assume it is 60A.

• What loads (if any) are hidden from your inverter. Typically, this could be an EV charger that has been wired up so it does not drain your house battery when charging your car. This is important because your inverter does not know if your EV charger is active so you need to set your import limit lower to avoid blowing your supply fuse.

The table below provides guidance on your import limit, based on your supply fuse, any hidden loads and how close to your fuse rating you want to run:



This is based on a supply of 220v because your supply voltage will drop when you draw maximum power and this increases the current for a given power. Use corresponds to a maxmimum current of 100%, 95%, 90% or 85% of your supply fuse rating. Lower power values reduce the stress on your fuse - if you expect to run sustained higher power draws, you should lower the maximum power to protect your supply fuse.

There are no values given for using an EV charger with a 60A supply. You can use a granny charger but (in the UK) you will need to get your supply upgraded to at least 80A before installation of a wall mounted 7kW EV charger.

There are 2 settings that control the import limit - current and power. These work together so the lowest setting will apply. The current limit should be set by your installer based on the installation to set a safe absolute upper limit.

Both settings can be viewed on the inverter front panel via Settings, 0000, On Grid, Export Control, ImportLimitCurrent / ImportLimitPower.

For example, if you have an 80A supply fuse, the current limit should be less than 80A. But, if you have a 7.2kW EV charger that is hidden, this would be reduced by 33A, so the value should be less than 47A.

If your import limit is set lower than your house load (without the house battery charging but possibly with your EV charging), your inverter may stop with the fault G100 State 3. This happens when the import limit is exceeded and the inverter is unable to reduce it's power consumption to correct this.

If you get this error and your import limits look ok, make sure your inverter firmware is up to date.