Solar Diverter

Solar diverters (also called immersion controllers) are third party devices used alongside a solar PV system which detect when the system is exporting to grid and redirects the power into a resistive load in the property, typically an immersion heating coil inside of a hot water tank. This means that the excess energy is actually used rather than exported and is another way of reducing import from the grid.

They are typically a self contained unit which used a CT coil to measure export moving to the grid to activate itself alongside some programming options such as time of use or maximum power to divert.

Depending on the location of the CT placement the solar diverter will either be read as a load by the inverter or will be outside the visibility of the inverter's readings/measurements. If the CT of the solar diverter is placed 'inside' of the CT of the inverter i.e. between the inverter CT and the the inverter itself) then it will read as a load which will more accurately track the power consumption and export readings. If the diverter CT is placed 'outside' i.e. between the inverter CT and the grid main incomer then it won't be tracked at all by the inverter - if this is the case then it will affect export figures because the inverter will see that the power was exported but it won't actually be going back to the grid.

They are typically recommneded for system which do little or no battery storage for generated energy. If you already have a hybrid inverter system with significant battery storage then you can store the power in the batteries and discharge them to cover the load for your hot water, meaning that the usefulness of a solar diverter as an addition to a system is more limited.